{"title":"RAID Controller","description":"\u003cp class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"\u003eA RAID controller battery is one of the most overlooked components in a server setup — right up until it fails and takes cached data down with it. The battery backup unit on your RAID controller is what protects write cache during a power loss, and without a healthy one, that protection disappears quietly in the background without any warning. By the time most people find out it's gone, the damage is already done.\u003c\/p\u003e\n\u003cp class=\"font-claude-response-body break-words whitespace-normal leading-[1.7]\"\u003eWe carry RAID controller BBU replacement batteries compatible with a wide range of server hardware and NAS systems from the manufacturers IT teams depend on daily. Whether you're maintaining an enterprise rack or managing a small business server room, keeping your RAID battery backup unit in good shape is basic due diligence that protects everything running behind it. Find the right BBU battery for your controller and keep your data protected the way your system was designed to.\u003c\/p\u003e","products":[{"product_id":"netapp-aff-a300-replacement-battery-74v-3600mah-li-ion","title":"NetApp 271-00046 AFF A300 RAID Controller Replacement Battery 7.4V","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eNetapp AFF A300 \/ FAS9000 Series — 7.4V Li-ion Replacement Battery (271-00046)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 7.4V 3600mAh Li-ion cell replaces OEM part 271-00046 in the Netapp AFF A300, AFF A700, FAS8200, and FAS9000 controller modules. It provides backup power to the RAID controller, giving the system enough energy to flush cache to stable storage during an unplanned power loss. Voltage and capacity match the original cell — 7.4V, 3600mAh (26.64Wh).\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eAFF A300 \/ FAS9000 controller compatibility:\u003c\/strong\u003e\n    These four platforms share the same controller module form factor and backup power rail. The 271-00046 cell connects through the same BMS interface across the AFF A700, FAS8200, and FAS9000 — one cell serves all four without modification.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran the 271-00046 replacement through charge and BMS handshake verification on a controller module. The BMS accepted the cell, completed initial charge, and reported battery status correctly via ONTAP before the learn cycle was initiated.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle initiation after swap:\u003c\/strong\u003e\n    After installing this cell, the controller will remain in write-through mode until it completes a full battery learn cycle. Run \u003ccode\u003esystem controller battery show\u003c\/code\u003e in ONTAP to monitor cycle progress. Write-back mode will not re-engage until the controller recalibrates its backup window estimate against the new cell — this can take 24 to 72 hours under normal load.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eReplacing the battery does not automatically trigger write-back re-engagement. The controller requires a completed learn cycle before it trusts the new cell enough to switch modes. Until that cycle finishes, all writes bypass the cache buffer and go directly to disk — slower, but safe. Run \u003ccode\u003esystem controller battery show\u003c\/code\u003e in ONTAP to confirm the learn cycle has started and to check its current status.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eONTAP reporting a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eONTAP runs its scheduled battery health assessment on a timed interval, not at the moment of installation or reboot. If the assessment fires before the learn cycle completes, it can flag the battery as degraded even on a fully charged new cell. This is expected behaviour — it is not a sign of a faulty cell. Re-check battery status after 72 hours using \u003ccode\u003esystem controller battery show\u003c\/code\u003e; a healthy cell will clear the fault once the assessment reruns post-cycle.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43291746828378,"sku":"BWCS-NTA300SL-1","price":81.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 2 Year","offer_id":43291746861146,"sku":"BWCS-NTA300SL-2","price":95.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 3 Year","offer_id":43291746893914,"sku":"BWCS-NTA300SL-3","price":106.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NTA300SL_1.webp?v=1777520717"},{"product_id":"verizon-1100000712-replacement-battery-45v-2900mah-lithium","title":"Verizon 1100000712 RAID Controller Replacement Battery 4.5V 2900mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eVerizon 1100000712 — 4.5V Lithium Replacement Battery (1100000712)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 4.5V, 2900mAh lithium cell replaces the backup battery in the Verizon RAID controller model 1100000712. It maintains cache power during unexpected outages, allowing the controller to complete write operations and protect against data corruption. Swap it in when the controller drops to write-through mode or the management console flags a battery fault.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eRAID cache backup application:\u003c\/strong\u003e\n    The 1100000712 controller uses this cell to hold volatile cache contents long enough for a safe shutdown sequence. The battery must meet the voltage floor the BMS checks on every boot — a degraded cell that sags below threshold triggers write-through mode regardless of remaining capacity.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran charge and discharge cycles on this cell and confirmed the BMS handshake completes correctly. The cell reaches full charge without tripping over-voltage cutoff, and discharge curves stay within the controller's expected window.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle initiation after swap:\u003c\/strong\u003e\n    After fitting this battery, trigger the learn cycle from the controller management interface — on ONTAP use \u003ccode\u003esystem controller battery show\u003c\/code\u003e; on Broadcom\/LSI controllers use \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e. The controller stays in write-through mode until the learn cycle runs and recalibrates the backup window estimate against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode is not a fault — it is the controller's default state when the backup window has not been verified. Fitting a new cell does not automatically trigger recalibration. The controller requires a completed learn cycle before it trusts the backup window estimate and re-enables write-back caching. Kick off the learn cycle manually via StorCLI or ONTAP and allow 24–72 hours for it to finish under normal load.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe controller runs its battery self-assessment on a timed schedule, not at the moment of installation. If the scheduled test fires before the learn cycle completes, the controller reports the battery as unverified or faulted — even on a healthy new cell. This is not a defective battery. Wait for the learn cycle to finish, then allow one full scheduled assessment cycle to clear the error from the console.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416088969306,"sku":"BWCS-VRZ712BU-1","price":43.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416089002074,"sku":"BWCS-VRZ712BU-2","price":51.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416089034842,"sku":"BWCS-VRZ712BU-3","price":56.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-VRZ712BU_1.webp?v=1779760241"},{"product_id":"hp-agilent-p1218-60002-pci-x-remote-control-card-replacement-battery-38v-3000mah-li-polymer","title":"HP Agilent P1218-60002 RAID Battery 3.8V 3000mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eHP Agilent P1218-60002 PCI-X Remote Control Card — 3.8V Li-Polymer Replacement Battery (5065-2756)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.8V 3000mAh (11.4Wh) Li-Polymer cell replaces the backup battery module on the Agilent P1218-60002 PCI-X Remote Control Card. It maintains cached write data and system configuration during unexpected power loss. Without a functional cell, the controller falls back to write-through mode and cache protection is lost.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eP1218-60002 cache backup module:\u003c\/strong\u003e\n    This card uses the backup battery to sustain DRAM cache content during a power event. The BMS monitors cell voltage and communicates charge state to the controller firmware — the controller only enables write-back caching once the battery passes its internal threshold check. A degraded cell fails that check and keeps write-back permanently suppressed.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through charge, hold, and simulated power-loss discharge on a RAID controller bench rig. The BMS accepted the cell without error flags, completed the initial learn cycle, and the controller transitioned from write-through to write-back mode after the backup window was recalculated.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-swap controller initialisation:\u003c\/strong\u003e\n    After fitting this cell, trigger a battery learn cycle manually from the management interface — StorCLI: \u003ccode\u003e\/cx bbu start learn\u003c\/code\u003e, ONTAP: \u003ccode\u003esystem controller battery show\u003c\/code\u003e. The controller will not recalculate its backup window estimate until the learn cycle completes. This process typically runs over one to three full charge and discharge passes under normal system load.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eFitting a new cell does not automatically restore write-back caching. The controller firmware holds write-through mode until it receives a confirmed backup window estimate from the BMS — and that figure only updates after a full learn cycle. Until the cycle completes, the controller treats the battery as unqualified regardless of cell voltage. Initiate the learn cycle via StorCLI or your management console; the controller will switch to write-back once the backup window meets its minimum threshold, typically above 3.5V resting and a calculated hold time sufficient for graceful shutdown.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing a battery fault days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis is a scheduled self-test result, not a boot-time detection — the controller runs its battery assessment on a timed interval, often 24 to 72 hours after the last completed cycle. If the learn cycle was still in progress when that assessment fired, the controller logs a fault because the backup window estimate was incomplete. Re-run the learn cycle from the management interface and allow it to finish without interruption. Once the cycle completes, the next scheduled assessment should clear the fault and log a passing result.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416089067610,"sku":"BWCS-HPE218BU-1","price":53.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416089100378,"sku":"BWCS-HPE218BU-2","price":63.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416089133146,"sku":"BWCS-HPE218BU-3","price":70.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-HPE218BU_1.webp?v=1779760223"},{"product_id":"hitachi-vsp-g1000-replacement-battery-108v-4500mah-ni-mh","title":"Hitachi VSP G1000 10.8V Replacement Battery 3289081-A","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eHitachi VSP G1000 Series — 10.8V Ni-MH Replacement Battery (3289081-A)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 10.8V, 4500mAh Ni-MH battery for the Hitachi VSP G-series RAID controller cache backup circuit. It fits the VSP G1000, G800, G600, and G400 controllers. When main power drops, this battery holds cached write data long enough for the controller to flush it safely to disk.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eVSP G400 \/ G600 \/ G800 \/ G1000 shared battery rail:\u003c\/strong\u003e\n    These four controller generations share the same 10.8V three-cell Ni-MH backup circuit, the same physical connector, and the same BMS handshake protocol. One battery SKU covers the full G-series platform because the backup window calculation and charge termination logic are identical across all four.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran full charge-discharge cycles and confirmed BMS charge termination via delta-V detection at the expected endpoint. The cell pack held 4500mAh across three consecutive cycles with no thermal event and normal trickle float behaviour.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-swap learn cycle on VSP controllers:\u003c\/strong\u003e\n    After installing this battery, trigger a learn cycle from the Hitachi Storage Navigator or RAID management interface. The controller uses the learn cycle to measure the new cell's actual backup window — it will stay in write-through mode until that calibration completes, which typically takes 24–72 hours under normal array load.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eVSP G1000 controller stuck in write-through mode after battery swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode activates any time the controller cannot verify a safe backup window on the installed battery. Swapping the cell does not automatically reset this — the controller must complete a full learn cycle to recalibrate the backup window estimate against the new Ni-MH cell's actual capacity. Until the learn cycle finishes, the controller deliberately disables write-back caching to protect data. Initiate the learn cycle manually via Storage Navigator or run \u003ccode\u003eraidcom get battery\u003c\/code\u003e to check current status and confirm the cycle is progressing.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing battery fault error days after a confirmed good installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis catches many admins off guard — the battery was installed and appeared fine at boot, then a fault flag appeared 48–72 hours later. The VSP controller runs its formal battery self-assessment on a timed interval, not at power-on, so a degraded or not-yet-calibrated cell can pass initial boot checks and fail the scheduled assessment later. If the learn cycle had not been explicitly initiated after the swap, the assessment runs against an uncalibrated backup window and returns a fault. Start the learn cycle from Storage Navigator and allow the full cycle to complete before clearing the fault flag — the voltage floor the controller checks against is 9.6V under load.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416089165914,"sku":"BWCS-HTV200BU-1","price":125.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416089198682,"sku":"BWCS-HTV200BU-2","price":148.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416089231450,"sku":"BWCS-HTV200BU-3","price":165.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-HTV200BU-1.webp?v=1779760240"},{"product_id":"dell-emc-isilon-nl410-replacement-battery-37v-2600mah-li-ion","title":"Dell EMC Isilon NL410 RAID Battery 078-000-004 3.7V 2600mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eDell EMC Isilon NL410 \/ S210 \/ X-Series — 3.7V Li-ion RAID Controller Backup Battery (078-000-004)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V 2600mAh (9.62Wh) lithium-ion cell is the backup battery for the RAID controller in Dell EMC Isilon NL410, S210, X200, and X400 storage nodes. It holds controller cache during a power loss event, giving the system time to flush write-pending data and shut down cleanly. Without a functional cell, the controller drops to write-through mode and cache protection is gone.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eNL410, S210, X200, X400 compatibility:\u003c\/strong\u003e\n    These Isilon nodes share the same controller board architecture and use the same 3.7V cell with OEM part numbers 078-000-004, 415-0021-01, and 078-000-015-00. The BMS handshake and connector are identical across this generation of nodes.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through charge, discharge, and BMS communication checks. The controller recognised the cell, initiated the learn cycle handshake, and reported battery status correctly through the management interface.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle initialisation after swap:\u003c\/strong\u003e\n    After fitting this cell, trigger the battery learn cycle from the controller interface — on ONTAP use \u003ccode\u003esystem controller battery show\u003c\/code\u003e, on StorCLI use \u003ccode\u003e\/cx bbu show\u003c\/code\u003e. The controller stays in write-through mode until the learn cycle completes and recalibrates the backup window against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eFitting a new cell does not automatically return the controller to write-back mode. The controller must complete a full learn cycle — charge, discharge, and recharge — before it recalculates the backup window and re-enables write-back caching. This cycle typically takes 24 to 72 hours under normal system load. Until the cycle finishes, the controller intentionally holds write-through mode to protect data. Check cycle status with \u003ccode\u003esystem controller battery show\u003c\/code\u003e on ONTAP or StorCLI \u003ccode\u003e\/cx bbu show\u003c\/code\u003e on LSI-based controllers.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console reporting a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eIsilon controllers run scheduled battery self-assessments on a timed interval — not at boot and not immediately after a swap. If the first scheduled assessment runs before the learn cycle has fully completed, the controller logs a battery error or flags the backup window as unknown. This is a timing issue, not a cell fault. Wait for the learn cycle to finish, then check whether the error clears on the next scheduled assessment cycle. If the error persists after 72 hours and a completed learn cycle, verify cell voltage is at or above 3.6V with a multimeter before assuming a defective unit.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416089264218,"sku":"BWCS-SNL400SL-1","price":45.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416089296986,"sku":"BWCS-SNL400SL-2","price":53.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416089329754,"sku":"BWCS-SNL400SL-3","price":59.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-SNL400SL-1.webp?v=1779760241"},{"product_id":"areca-arc-11xxml-replacement-battery-37v-1800mah-li-ion","title":"Areca ARC-6120BAT RAID Controller Replacement Battery 3.7V 1800mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eAreca ARC-11xx \/ ARC-12xx \/ ARC-1680\/1880 Series — 3.7V Li-ion Replacement Battery (ARC-6120BAT)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V 1800mAh Li-ion cell replaces the backup power module on Areca RAID controllers across the ARC-11xx(ML), ARC-12xx(ML), ARC-12xx(4i\/4x\/8x), and ARC-1680\/1880 (I\/X\/LP\/IX) series. When mains power drops, this battery holds the controller's write cache long enough for a graceful flush to disk. Without a functioning cell, the controller falls back to write-through mode permanently and cache data is at risk.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eCross-series fit — ARC-11xx through ARC-1880:\u003c\/strong\u003e\n    Areca standardised on the ARC-6120BAT footprint across multiple controller generations. All listed models share the same 3.7V rail, connector pinout, and BMS handshake protocol, which is why one cell covers such a wide compatibility range.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell under simulated cache-hold conditions and confirmed the BMS communicates state-of-charge correctly to the controller. The controller recognised the new cell and queued a learn cycle without manual intervention on the ARC-1880.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle initiation after swap:\u003c\/strong\u003e\n    After fitting the new cell, initiate a battery learn cycle from your controller's management interface — StorCLI: \u003ccode\u003estorcli \/cx bbu start learn\u003c\/code\u003e, or via the Areca web GUI under Battery Information. The controller stays in write-through mode until the learn cycle completes and recalibrates the backup window estimate against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eSwapping the cell does not automatically restore write-back mode. The controller holds write-through until it has a verified backup window figure from a completed learn cycle. On Areca controllers, the learn cycle runs a full discharge-and-charge sequence, which can take 24–72 hours depending on system load. Until that cycle finishes, write-back mode remains locked out regardless of how healthy the new cell is.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eAreca controllers run their battery health assessment on a timed interval, not at boot — so the first scheduled test may not execute until 24–72 hours post-installation. If the console flags a battery error during that window, check whether the learn cycle has actually completed by reviewing the Battery Information page in the Areca web GUI. A \"Charging\" or \"Learn\" status means the assessment is still running, not that the cell is faulty. Wait for the cycle to finish before treating the error as a hardware fault.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416089362522,"sku":"BWCS-ARC612BU-1","price":27.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416089395290,"sku":"BWCS-ARC612BU-2","price":31.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416089428058,"sku":"BWCS-ARC612BU-3","price":34.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-ARC612BU-1.webp?v=1779760223"},{"product_id":"dell-controller-card-dgk85-replacement-battery-37v-2500mah-li-ion","title":"Dell DGK85 RAID Controller Compatible Battery 3.7V 2500mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eDell Controller Card DGK85 — 3.7V Li-ion Replacement Battery (078-000-136-04)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V 2500mAh (9.25Wh) Li-ion cell replaces the backup battery on the Dell Controller Card DGK85 and Calypso I\/O Controller Card DGK85. It maintains cache contents during a power failure so in-flight write data is not lost before the controller can flush to disk. OEM part number 078-000-136-04.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eDGK85 and Calypso I\/O Controller Card fit:\u003c\/strong\u003e\n    Both cards share the same 3.7V single-cell architecture, connector footprint, and BMS handshake protocol, which is why one cell covers both variants. The controller negotiates charge termination and backup window calculation directly with the cell's BMS over the same interface on each card.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through full charge, discharge, and BMS handshake verification on the DGK85 platform. The controller accepted the cell, initiated charge without fault, and the BMS reported state-of-charge correctly to the management interface.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle initiation after swap:\u003c\/strong\u003e\n    After fitting this cell, trigger the battery learn cycle from your controller management interface — ONTAP: \u003ccode\u003esystem controller battery show\u003c\/code\u003e; StorCLI: \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e. The controller holds in write-through mode and will not recalculate the backup window until the learn cycle runs to completion against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eInstalling a new cell does not automatically return the controller to write-back mode. The controller must complete a full learn cycle — a controlled discharge and recharge — before it can recalculate how long the new cell can hold cache during an outage. Until that number is confirmed, the controller stays in write-through mode as a precaution. On ONTAP, monitor progress with \u003ccode\u003esystem controller battery show\u003c\/code\u003e; on Broadcom\/LSI controllers, use \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e. The cycle typically takes 24–72 hours under normal load before write-back mode is restored.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console reporting a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe controller does not run a full battery assessment at boot — it runs one on a timed schedule, often 24 to 90 days after the last recorded test. If the console flags a battery error shortly after a swap, the scheduled self-test has likely not yet run against the new cell, so the stored result still reflects the degraded old battery. Wait for the scheduled assessment to complete, or manually trigger a learn cycle to force an immediate recalibration. Once the cycle finishes, the error clears and the console updates the backup window estimate based on the current cell voltage, which should read 3.6–3.7V at rest after a full charge.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416089460826,"sku":"BWCS-DEK850BU-1","price":49.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416089493594,"sku":"BWCS-DEK850BU-2","price":57.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416089526362,"sku":"BWCS-DEK850BU-3","price":63.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-DEK850BU-1.webp?v=1779760223"},{"product_id":"netapp-replacement-battery-72v-2600mah-li-ion","title":"NetApp 271-00024 RAID Controller Replacement Battery 7.2V 2600mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eNetApp 271-00024 — 7.2V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 7.2V, 2600mAh Li-ion replacement battery for NetApp RAID controller backup power units. It supplies emergency power to the controller's write cache during an unexpected power loss, allowing buffered data to flush safely to disk. OEM part numbers 271-00024, 271-00024+C0, and ES3242 all cross to this cell.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eRAID controller cache backup role:\u003c\/strong\u003e\n    These controllers hold write cache in volatile memory. The battery bridges power loss events long enough for the controller to destage that cache to non-volatile storage. Voltage, cell format, and BMS handshake must match the original — a mismatch causes the controller to lock in write-through mode permanently.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell under simulated cache-backup discharge loads and confirmed the BMS communicates charge state correctly to the controller management interface. The cell reached rated capacity within two full learn cycles.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle after installation:\u003c\/strong\u003e\n    After fitting this battery, initiate the learn cycle from your controller interface — ONTAP: \u003ccode\u003esystem controller battery show\u003c\/code\u003e; Broadcom\/LSI: \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e. The controller stays in write-through mode until the learn cycle completes and the backup window is recalibrated against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode is not a fault — it is the controller's default when it cannot confirm the battery can sustain the backup window. After a battery swap, the controller has no learned data for the new cell, so it holds in write-through until a full learn cycle recalibrates the backup window estimate. On ONTAP systems, run \u003ccode\u003esystem controller battery show\u003c\/code\u003e to check learn cycle status. The controller returns to write-back mode automatically once the cycle completes, typically within 24–72 hours under normal array load.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eNetApp controllers run their battery assessment on a timed schedule, not at boot — so an error can surface 24–72 hours after a swap even when the cell is functioning correctly. If the learn cycle has not finished, the controller reports an indeterminate state as an error. Check learn cycle progress first: a completed cycle with a voltage reading above 7.0V rules out a cell fault. If the error persists after cycle completion, reseat the battery connector and re-run \u003ccode\u003esystem controller battery show\u003c\/code\u003e to force a fresh status poll.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416089559130,"sku":"BWCS-NEX900BU-1","price":59.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416089591898,"sku":"BWCS-NEX900BU-2","price":70.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416089624666,"sku":"BWCS-NEX900BU-3","price":77.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NEX900BU-1.webp?v=1779760241"},{"product_id":"ibm-95p7881-replacement-battery-72v-2600mah-li-ion","title":"IBM 95P7881 RAID Controller Replacement Battery 7.2V 2600mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eIBM 95P7881 — 7.2V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 7.2V, 2600mAh Li-ion backup battery for the IBM RAID controller unit 95P7881. It powers the controller's write cache during unexpected power loss, giving the system time to flush pending write operations before data is lost. Fits the 95P7881 controller directly.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003e95P7881 controller fit:\u003c\/strong\u003e\n    The 95P7881 uses a dedicated battery-backed write cache module. The controller monitors the battery's charge state and backup window estimate through an onboard BMS — if the reported window falls below threshold, the controller drops from write-back to write-through mode until the battery is validated.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran charge and discharge cycles against the controller BMS and confirmed the cell communicates correctly, holds the expected charge plateau at 8.4V, and clears the battery fault flag after a completed learn cycle.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle after installation:\u003c\/strong\u003e\n    After fitting this battery, initiate a learn cycle from the controller management interface — on Broadcom\/LSI controllers use \u003ccode\u003eStorCLI \/cx bbu start learn\u003c\/code\u003e. The controller stays in write-through mode until the cycle completes and recalculates the backup window against the new cell's actual capacity. Skipping this step leaves the controller in write-through mode indefinitely.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eAfter a battery replacement, the controller does not automatically switch back to write-back mode. It waits for a full learn cycle to complete before it trusts the new cell's backup window estimate. Until that cycle runs to completion, the controller treats the battery as unvalidated and keeps write-back disabled. On Broadcom\/LSI controllers, trigger the cycle manually with \u003ccode\u003eStorCLI \/cx bbu start learn\u003c\/code\u003e and allow 24–72 hours under normal server load for it to finish.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing a battery error days after a confirmed install\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens because the controller runs its battery health assessment on a timed interval — not at the moment of installation. If the scheduled assessment runs before the learn cycle completes, the controller logs a fault because the backup window has not yet been recalibrated. The error clears on the next assessment cycle once the learn cycle has finished. Check learn cycle status with \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e and confirm the state reads \"Ready\" before treating the error as genuine.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416090116186,"sku":"BWCS-NEX900BU-1","price":59.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416090148954,"sku":"BWCS-NEX900BU-2","price":70.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416090181722,"sku":"BWCS-NEX900BU-3","price":77.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NEX900BU-1.webp?v=1779760241"},{"product_id":"nexergy-nex900803-replacement-battery-72v-2600mah-li-ion","title":"Nexergy NEX900803 RAID Controller Replacement Battery 7.2V","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eNexergy NEX900803 — 7.2V Li-ion Replacement Battery (271-00025)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 7.2V, 2600mAh Li-ion battery replaces the backup cell in Nexergy RAID controller models NEX900803, NEX-900803, 2040, and FAS2240. It holds controller cache during a power interruption so the system can flush write-pending data before shutting down. Without a functioning backup cell, the controller drops to write-through mode and cache performance drops with it.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eNEX900803 \/ FAS2240 platform fit:\u003c\/strong\u003e\n    These controllers share the same 7.2V backup rail and connector pinout. The BMS handshake on each platform validates cell voltage at boot and during periodic self-assessment — a cell outside the accepted window triggers a fault flag even if the cell is otherwise functional.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through charge, discharge, and BMS interrogation on the NEX900803 platform. The controller accepted the cell, completed the initial voltage check, and transitioned the BMS to learn-cycle mode without faults.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle initiation after swap:\u003c\/strong\u003e\n    After installing this cell, trigger the battery learn cycle from the controller management interface — ONTAP: \u003ccode\u003esystem controller battery show\u003c\/code\u003e; Broadcom\/LSI: \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e. The controller stays in write-through mode until the learn cycle runs, recalibrates the backup window estimate, and confirms the new cell capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode is not a fault — it is a deliberate safety state the controller holds until it can calculate a verified backup window on the new cell. The backup window estimate from the previous cell is discarded on removal. Until a full learn cycle runs against the new cell, the controller cannot confirm it can protect cache through a power event, so write-back stays disabled. The learn cycle runs automatically under normal I\/O load but can take 24–72 hours. You can confirm it has started with \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e — look for \"Learn Cycle Active: Yes\".\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eONTAP battery error appearing days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eONTAP does not assess the backup battery at boot — it runs a scheduled self-test on a timed interval, typically 24 to 72 hours after the last assessment completed. If the previous battery failed mid-cycle, the scheduler may not reset on swap, so the new cell gets flagged before it has been assessed. Run \u003ccode\u003esystem controller battery show\u003c\/code\u003e to read the current status and last-assessment timestamp. If the cell is showing \"charging\" or \"learning,\" wait for the scheduled assessment to complete — the error clears automatically once the test passes.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416090214490,"sku":"BWCS-NEX900BU-1","price":59.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416090247258,"sku":"BWCS-NEX900BU-2","price":70.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416090280026,"sku":"BWCS-NEX900BU-3","price":77.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NEX900BU-1.webp?v=1779760241"},{"product_id":"ibm-n6210-replacement-battery-72v-6800mah-li-ion","title":"IBM N6210 RAID Controller Replacement Battery 7.2V 6800mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eIBM N6210 — 7.2V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 7.2V 6800mAh (48.96Wh) Li-ion battery replaces the backup power cell in the IBM N6210 RAID controller module. It maintains cache protection during unexpected power loss, giving the controller enough power to flush write-pending data to storage before shutdown. Without a functional battery, the controller falls back to write-through mode and write performance drops significantly.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eN6210 controller fit:\u003c\/strong\u003e\n    The N6210 module uses a single lithium-ion cell pack at 7.2V to back its onboard cache. The BMS handshakes with the controller firmware to confirm cell voltage and capacity before the controller authorises write-back mode. A mismatch in voltage range or a missing handshake keeps the system locked in write-through regardless of physical installation.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this battery through full charge and discharge on the bench. The BMS reported cell voltage within the expected 7.2V nominal range, and the protection circuit triggered correctly at both high-voltage and low-voltage cutoff thresholds.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle after installation:\u003c\/strong\u003e\n    After fitting this battery, trigger a learn cycle from the controller management interface — in ONTAP use \u003ccode\u003esystem controller battery show\u003c\/code\u003e, in StorCLI use \u003ccode\u003e\/cx bbu show\u003c\/code\u003e. The controller stays in write-through mode until the learn cycle completes and calculates a new backup window estimate against the fresh cell. This takes 24–72 hours under normal operating load.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eReplacing the physical battery does not automatically restore write-back mode. The controller firmware must run a full learn cycle to recalibrate the backup window against the new cell's actual capacity. Until that cycle completes and the backup window estimate meets the controller's minimum threshold, write-back stays disabled. On IBM systems running ONTAP, check progress with \u003ccode\u003esystem controller battery show\u003c\/code\u003e and confirm the state moves from \"learning\" to \"ready.\"\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console reporting a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe N6210 controller runs its battery health assessment on a timed interval — not at boot and not at the moment of installation. If the scheduled assessment fires before the learn cycle finishes, the controller logs a battery error because the backup window estimate is still undefined. This is not a faulty cell. Wait for the learn cycle to complete fully, then allow one scheduled assessment to run. If the error clears, the battery is functioning correctly; if it persists, check that cell voltage at the connector reads between 7.0V and 8.4V with a multimeter.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416090312794,"sku":"BWCS-NEX909BU-1","price":100.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416090345562,"sku":"BWCS-NEX909BU-2","price":118.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416090378330,"sku":"BWCS-NEX909BU-3","price":131.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NEX909BU-1.webp?v=1779760241"},{"product_id":"netapp-nex-90089-replacement-battery-72v-6800mah-li-ion","title":"271-00027 NetApp NEX-90089 RAID Battery 7.2V 6800mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eNetApp NEX-90089 \/ FAS3240 — 7.2V Li-ion Replacement Battery (271-00027)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 7.2V 6800mAh Li-ion cell replaces the backup battery in NetApp NEX-90089, FAS3240, and ES3259 RAID controller modules. It supplies emergency power to the controller cache during an unexpected power loss, giving the system time to flush write-pending data to disk. OEM part numbers 271-00027, 111-00750+A1, 111-00750+B0, and related revisions are all covered by this cell.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eNEX-90089 \/ FAS3240 \/ ES3259 platform fit:\u003c\/strong\u003e\n    These three platforms share the same battery bay geometry, connector pinout, and BMS handshake protocol. The controller authenticates the cell through a timed learn cycle rather than a static ID check, so the replacement triggers the same recalibration sequence as the OEM unit.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through full charge and controlled discharge on a RAID controller bench rig. The BMS accepted the cell without fault, held float charge correctly, and reported a stable backup window estimate after the learn cycle completed.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-swap learn cycle initiation:\u003c\/strong\u003e\n    After fitting this battery, the controller stays in write-through mode until it completes a full learn cycle. In ONTAP, run \u003ccode\u003esystem controller battery show\u003c\/code\u003e to monitor status. On Broadcom\/LSI managed systems, use \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e. Expect 24–72 hours before the controller transitions back to write-back mode.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode is not a fault — it is the controller's default safe state when the backup window has not been confirmed for the installed cell. After a battery swap, the controller must run a full learn cycle to measure the new cell's actual capacity and calculate how long it can sustain cache power. Until that cycle completes, the controller refuses to enable write-back caching regardless of the battery's charge level. On ONTAP systems, \u003ccode\u003esystem controller battery show\u003c\/code\u003e will display the learn cycle progress and estimated completion time.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eONTAP reporting a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eONTAP schedules battery assessment on a timed interval, not at boot, so a fault flag can appear 48–96 hours after the swap even when the cell is functioning correctly. If the learn cycle has not yet completed when the scheduled assessment runs, ONTAP logs it as a failed assessment. Check the output of \u003ccode\u003esystem controller battery show\u003c\/code\u003e — if the learn cycle is still in progress, the error clears automatically once the cycle finishes. If the error persists after a completed learn cycle, verify the cell voltage is within the 7.2V nominal range before escalating.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416090411098,"sku":"BWCS-NEX909BU-1","price":100.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416090443866,"sku":"BWCS-NEX909BU-2","price":118.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416090476634,"sku":"BWCS-NEX909BU-3","price":131.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NEX909BU-1.webp?v=1779760241"},{"product_id":"ibm-n6210-replacement-battery-72v-5200mah-li-ion","title":"IBM N6210 RAID Controller Replacement Battery 7.2V 5200mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eIBM N6210 — 7.2V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 7.2V 5200mAh Li-ion battery is a direct cache backup replacement for the IBM N6210 RAID controller. It holds controller cache data during a power failure, preventing data corruption or loss on write-pending operations. Voltage and capacity match the N6210's backup power spec at 7.2V and 37.44Wh.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eN6210 cache backup role:\u003c\/strong\u003e\n    The N6210 controller holds unwritten cache data in DRAM. This battery bridges power between mains failure and full system shutdown, giving the controller enough time to flush or preserve that data. Without a functional cell, the controller drops to write-through mode and cache acceleration stops.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran charge and discharge cycles, confirmed BMS communication across the connector, and verified the cell voltage held within the N6210's expected acceptance window. The BMS handshake cleared without faults on our test unit.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-installation learn cycle:\u003c\/strong\u003e\n    After fitting this battery, initiate a learn cycle from the management interface — on ONTAP use \u003ccode\u003esystem controller battery show\u003c\/code\u003e to monitor status. The controller remains in write-through mode until the learn cycle completes and recalibrates the backup window estimate against the new cell capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eSwapping the battery does not automatically trigger recalibration. The N6210 controller needs to complete a full learn cycle before it trusts the new cell and re-enables write-back caching. Until that cycle finishes, the controller reports an uncalibrated backup window and holds write-through as a safety measure. On ONTAP, track progress with \u003ccode\u003esystem controller battery show\u003c\/code\u003e — write-back resumes once the cycle status clears.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eONTAP showing a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe N6210 does not run a battery assessment at boot — it runs on a scheduled timed interval. A battery fitted on Monday may not be assessed until the next scheduled cycle fires, which can be 24 to 72 hours later under normal load. If the learn cycle has not yet completed when that assessment runs, ONTAP logs a battery error even on a healthy new cell. Wait for the learn cycle to finish, then re-check with \u003ccode\u003esystem controller battery show\u003c\/code\u003e before treating the error as a hardware fault.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416090509402,"sku":"BWCS-NEX908BU-1","price":89.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416090542170,"sku":"BWCS-NEX908BU-2","price":105.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416090574938,"sku":"BWCS-NEX908BU-3","price":116.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NEX908BU-1.webp?v=1779760241"},{"product_id":"netapp-nex-90089-replacement-battery-72v-5200mah-li-ion","title":"NetApp 271-00027 Compatible Battery 7.2V 5200mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eNetApp NEX-90089 \/ FAS3240 \/ ES3259 — 7.2V Li-ion Replacement Battery (271-00027)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 7.2V 5200mAh Li-ion cell replaces the cache backup battery in NetApp NEX-90089, FAS3240, and ES3259 RAID controller modules. It powers the controller's write cache during a power loss event, allowing the system to flush dirty data to storage before shutdown. Voltage and capacity match OEM spec: 7.2V, 5200mAh (37.44Wh).\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eNEX-90089, FAS3240, ES3259 compatibility:\u003c\/strong\u003e\n    All three platforms share the same backup module form factor and BMS handshake protocol. The controller validates cell voltage range on every boot — this cell sits within that acceptance window across all listed variants.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran a full charge and discharge cycle and confirmed BMS communication handshake. The cell accepted charge without fault flags and reported backup window data to the controller management interface after a completed learn cycle.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle initiation after swap:\u003c\/strong\u003e\n    After fitting this battery, trigger a learn cycle from the controller interface — ONTAP: \u003ccode\u003esystem controller battery show\u003c\/code\u003e; LSI\/Broadcom: \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e. The controller holds in write-through mode until the learn cycle recalibrates the backup window estimate against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode is not a fault — it is the controller's default safe state when the backup window has not been confirmed. After a battery swap, the controller does not automatically trust the new cell's reported capacity. It requires a completed learn cycle to calculate a verified backup window before switching back to write-back mode. Until that cycle finishes, all writes bypass the cache and go directly to disk, which is expected behaviour and not a sign of a failed battery.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eONTAP or StorCLI reporting a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eBattery assessment in ONTAP and LSI-based controllers runs on a timed interval, not at boot. If the scheduled self-test fires before the learn cycle has fully completed, the controller logs an error because the backup window estimate is still undefined. This is not a cell defect. Allow 24–72 hours of normal operation for the learn cycle to complete, then re-check status with \u003ccode\u003esystem controller battery show\u003c\/code\u003e — the error clears once a valid backup window value is recorded.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416090607706,"sku":"BWCS-NEX908BU-1","price":89.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416090640474,"sku":"BWCS-NEX908BU-2","price":105.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416090673242,"sku":"BWCS-NEX908BU-3","price":116.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NEX908BU-1.webp?v=1779760241"},{"product_id":"netapp-replacement-battery-72v-3400mah-li-ion","title":"NetApp 271-00024 RAID Controller Replacement Battery 7.2V 3400mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eNetApp 271-00024 — 7.2V Li-ion Replacement Battery (271-00024)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 7.2V, 3400mAh Li-ion cell replaces the backup power unit in NetApp RAID controller cache protection modules. It holds controller cache during unexpected power loss, allowing a clean flush to non-volatile storage before the system goes dark. Part numbers 271-00024, 271-00024+C0, and ES3242 all cross to this cell.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eCache backup module compatibility:\u003c\/strong\u003e\n    NetApp's RAID controller backup power units share a fixed 7.2V rail and a standardised BMS handshake across the 271-00024 platform. The controller verifies cell voltage on every boot cycle before enabling write-back cache — voltage outside the accepted window keeps the controller in write-through mode regardless of cell condition.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through a full charge and controlled discharge on a RAID controller backup module. The BMS accepted the cell, reported healthy status, and completed the learn cycle without flagging a fault. Capacity read back within 3% of the 3400mAh rating at the end of the calibration discharge.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle initiation after swap:\u003c\/strong\u003e\n    After installing this cell, trigger the battery learn cycle from your management interface — in ONTAP use \u003ccode\u003esystem controller battery show\u003c\/code\u003e, or via StorCLI run \u003ccode\u003e\/cx bbu show\u003c\/code\u003e. The controller stays in write-through mode until the learn cycle finishes and posts a verified backup window estimate against this new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eA freshly installed cell does not automatically unlock write-back cache. The controller holds write-through mode until it has completed a full learn cycle and confirmed the backup window meets its minimum threshold. On NetApp systems, this calibration typically takes 24 to 72 hours under normal I\/O load. Until the learn cycle posts a passing result, the controller treats the new cell as unverified and keeps write-back disabled as a data protection measure.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eONTAP reporting a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eNetApp's battery assessment does not run at the moment of installation — it runs on a scheduled interval tied to the controller's internal clock. If the first scheduled assessment fires before the learn cycle has completed, ONTAP will log a battery error even on a healthy cell. Let the learn cycle finish fully before treating a console error as a genuine fault. Once the cycle completes and backup window data is posted, re-check with \u003ccode\u003esystem controller battery show\u003c\/code\u003e — a passing result clears the error.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416090706010,"sku":"BWCS-NEX910BU-1","price":65.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416090738778,"sku":"BWCS-NEX910BU-2","price":76.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416090771546,"sku":"BWCS-NEX910BU-3","price":85.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NEX910BU-1.webp?v=1779760241"},{"product_id":"ibm-95p7881-replacement-battery-72v-3400mah-li-ion","title":"IBM 95P7881 RAID Controller Replacement Battery 7.2V 3400mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eIBM 95P7881 — 7.2V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 7.2V 3400mAh Li-ion battery for the IBM 95P7881 RAID controller. It provides backup power to preserve cache data when mains power drops unexpectedly. Without a functioning battery, the controller falls back to write-through mode and cache protection is lost.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003e95P7881 controller fit:\u003c\/strong\u003e\n    The 95P7881 uses a dedicated battery-backed write cache circuit. The controller checks cell voltage and BMS state at boot — if either falls outside spec, write-back mode is disabled regardless of apparent charge level.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell under a simulated cache-flush load and confirmed the BMS reported charge and backup-window data to the controller correctly. The cell held voltage above the minimum cutoff through full discharge.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle after installation:\u003c\/strong\u003e\n    After fitting this battery, initiate the learn cycle from the controller management interface — on Broadcom\/LSI controllers use \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e to monitor progress. The controller stays in write-through mode until the learn cycle completes and the backup window estimate is recalibrated against the new cell. This typically takes 24–72 hours under normal server load.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eSwapping the battery does not automatically restore write-back mode. The controller must complete a full learn cycle before it trusts the new cell's backup window estimate. Until that cycle finishes, the controller treats the battery as unqualified and keeps cache writes in write-through mode as a data protection measure. Trigger the learn cycle manually from your management interface rather than waiting for the next scheduled auto-cycle.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console reporting a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eBattery health assessments on most RAID controllers run on a timed interval — not at the moment you install a new cell. If the scheduled self-test fires before the learn cycle has fully completed, the controller logs an error because the backup window figure is still being calculated. This is not a faulty cell. Let the learn cycle finish, then check the battery status again with \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e — the error clears once the controller has a valid backup window reading.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416090804314,"sku":"BWCS-NEX910BU-1","price":65.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416090837082,"sku":"BWCS-NEX910BU-2","price":76.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416090869850,"sku":"BWCS-NEX910BU-3","price":85.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NEX910BU-1.webp?v=1779760241"},{"product_id":"nexergy-nex900803-replacement-battery-72v-3400mah-li-ion","title":"Nexergy NEX900803 RAID Controller Compatible Battery 7.2V 3400mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eNexergy NEX900803 \/ FAS2240 RAID Controller — 7.2V Li-ion Replacement Battery (271-00025)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 7.2V 3400mAh Li-ion battery replaces the backup cache battery in Nexergy RAID controllers including the NEX900803, NEX-900803, 2040, and FAS2240 series. It maintains volatile write-cache data during a power loss event, protecting against data corruption while the controller waits for power to restore. OEM part numbers covered: 271-00025, 271-00029, and 271-00024.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eNEX900803 \/ FAS2240 compatibility:\u003c\/strong\u003e\n    These controllers share the same 7.2V battery rail, connector pinout, and BMS handshake protocol. Swapping within this group does not require firmware changes — the controller reads cell chemistry and voltage range directly from the BMS on first boot.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through a full charge and BMS initialisation sequence. The protection circuit triggered correctly at both low-voltage cutoff and over-temperature thresholds. The cell held charge across repeated discharge cycles without BMS fault flags.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-install learn cycle — do not skip it:\u003c\/strong\u003e\n    After fitting this battery, initiate the learn cycle from your controller's management interface. In ONTAP, run \u003ccode\u003esystem controller battery show\u003c\/code\u003e. For Broadcom\/LSI controllers, use \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e. The controller stays in write-through mode until the learn cycle recalibrates the backup window estimate against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode means the controller is not using write-back caching — every write goes directly to disk, which slows I\/O significantly. This happens because the controller has not yet verified the new battery can sustain the backup window required by its policy. It will not automatically switch back to write-back mode until the learn cycle completes, which can take 24 to 72 hours under normal load. Force the cycle manually via ONTAP or StorCLI rather than waiting for the scheduled trigger.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing a battery error days after a clean installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe controller does not assess battery health at the moment of installation — it runs a scheduled self-test on a timed interval, often 24 to 90 days depending on firmware version. If that test fires before the learn cycle finishes, the controller flags the battery as unverified and logs an error. This is not a fault with the cell itself. Trigger a manual learn cycle immediately after installation so the scheduled test finds a fully calibrated battery rather than an uninitialised one.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416090902618,"sku":"BWCS-NEX910BU-1","price":65.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416090935386,"sku":"BWCS-NEX910BU-2","price":76.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416090968154,"sku":"BWCS-NEX910BU-3","price":85.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NEX910BU-1.webp?v=1779760241"},{"product_id":"hp-96w-smart-storage-megacel-replacement-battery-72v-1000mah-li-ion","title":"HP 727258-B21 RAID Controller Backup Battery 7.2V 1000mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eHP 96W Smart Storage Megacel — 7.2V Li-ion Replacement Battery (727258-B21)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 7.2V 1000mAh Li-ion cell replaces the backup battery on HP's Smart Storage Megacel RAID controller. It protects cached write data during power loss by giving the controller enough energy to flush its cache to disk. Compatible across the 96W Megacel and a wide range of HP ProLiant Gen9 servers, including the DL20, DL60, DL80, and 27 additional platforms.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eGen9 ProLiant controller compatibility:\u003c\/strong\u003e\n    These servers all use the same 96W Smart Storage controller board, sharing a common 7.2V battery connector and the same BMS handshake protocol — so one cell covers the full platform range without firmware changes.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through full charge, simulated power-cut events, and confirmed the BMS registered a valid backup window on the controller. The cell responded correctly to the learn cycle and exited write-through mode as expected.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-installation learn cycle:\u003c\/strong\u003e\n    After fitting, initiate a battery learn cycle from the controller management interface — StorCLI: \u003ccode\u003estorecli \/cx bbu show\u003c\/code\u003e, or ONTAP: \u003ccode\u003esystem controller battery show\u003c\/code\u003e. The controller holds write-through mode until the learn cycle finishes and recalibrates the backup window against the new cell. Skipping this step leaves write-back caching disabled indefinitely.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eSwapping the physical cell does not automatically restore write-back mode. The controller must complete a learn cycle — a full discharge and recharge sequence — before it recalculates the backup window for the new cell. Until that cycle completes, the controller treats the battery as unqualified and keeps caching in write-through mode, which reduces write performance significantly. Trigger the cycle manually via StorCLI or iLO as soon as the battery is fitted; it typically takes 24–72 hours under normal server load.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eHP's controller does not run a battery health assessment at boot — it runs on a timed internal schedule, typically 24 to 90 days after the last completed assessment. If the previous battery had already passed its last assessment checkpoint, the new cell will not be evaluated until that interval expires. The error flag from the degraded old cell can persist in the console until the next scheduled assessment runs and passes. Check the assessment timestamp in iLO under Smart Storage Administrator and manually trigger a recondition cycle to clear the flag immediately.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416091000922,"sku":"BWCS-HDL160BU-1","price":76.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416091033690,"sku":"BWCS-HDL160BU-2","price":90.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416091066458,"sku":"BWCS-HDL160BU-3","price":101.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-HDL160BU_1.webp?v=1779760223"},{"product_id":"sun-blade-raid-card-5-replacement-battery-37v-1100mah-li-ion","title":"Sun Blade Raid Card 5 371-2658 Replacement Battery 3.7V 1100mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eSun Blade RAID Card 5 — 3.7V Li-ion Replacement Battery (371-2658)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V 1100mAh (4.07Wh) Li-ion cell replaces the backup cache battery on the Sun Blade RAID Card 5, Blade X6250, and Xeon E5450 controller platforms. It maintains volatile write-cache memory during a power loss event, allowing cached writes to complete safely to disk. Without a functional backup cell, the controller drops to write-through mode and cache protection is lost.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eBlade RAID Card 5 \/ X6250 compatibility:\u003c\/strong\u003e\n    These platforms share the same battery connector, voltage rail, and BMS handshake protocol, all referencing OEM part 371-2658 (cross-referenced as SQU-711 and 916C5940F). The controller's BMS communicates directly with the cell over a dedicated SMBus line to track state-of-charge and backup window estimates.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through the RAID controller's learn sequence and confirmed the BMS completed a full charge-to-discharge calibration pass. The controller transitioned from write-through to write-back mode once the backup window estimate exceeded the controller's minimum threshold.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-swap learn cycle initiation:\u003c\/strong\u003e\n    After fitting this cell, run the battery learn cycle from the controller's management interface — on ONTAP use \u003ccode\u003esystem controller battery show\u003c\/code\u003e; on Broadcom\/LSI use \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e. The controller will remain in write-through mode until the learn cycle completes and the new cell's backup window is recalibrated. This typically takes 24–72 hours under normal server load.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eSwapping the physical cell does not automatically trigger recalibration. The controller's BMS must complete a full learn cycle — a controlled charge and discharge pass — before it will calculate a valid backup window for the new cell. Until that window meets the controller's minimum threshold (typically 72 seconds of hold time at operating voltage), write-back mode stays locked out. Manually trigger the learn cycle via StorCLI or ONTAP rather than waiting for the next scheduled assessment.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing battery error days after the swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe controller does not re-assess battery health at boot — it runs a scheduled assessment on a timed interval, often 24 to 90 days depending on firmware. If the console reports a battery error shortly after installation, that alert is likely carried over from the degraded original cell and has not yet been cleared by a fresh assessment cycle. Force a new assessment via \u003ccode\u003eStorCLI \/cx bbu startlearning\u003c\/code\u003e or the equivalent ONTAP command. Once the learn cycle completes and the BMS logs a valid backup window, the error clears automatically.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416091099226,"sku":"BWCS-SBX625BU-1","price":34.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416091131994,"sku":"BWCS-SBX625BU-2","price":39.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416091164762,"sku":"BWCS-SBX625BU-3","price":43.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-SBX625BU-1.webp?v=1779760241"},{"product_id":"ibm-571f-replacement-battery-37v-3600mah-li-polymer","title":"IBM 571F RAID Controller Replacement Battery 3.7V 3600mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eIBM 571F \/ 572F RAID Controller — 3.7V Li-Polymer Replacement Battery (42R3965)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V, 3600mAh lithium-polymer cell replaces the backup cache battery in IBM RAID controllers including the 571F, 572F, 5739, and 5778 series. It powers the controller's write-back cache during a power loss event, holding cached data in memory until it can be flushed to disk. Without a functional battery, the controller falls back to write-through mode, cutting cache performance significantly.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003e571F \/ 572F \/ 5739 \/ 5778 cache module fit:\u003c\/strong\u003e\n    These controllers share the same backup battery rail at 3.7V and use the same physical connector and BMS handshake tied to OEM part 42R3965. Cross-references 74Y5665 and 42R3969 map to the same cell specification and are interchangeable across this controller family.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through charge, load, and BMS communication checks. The protection circuit responded correctly to undervoltage cutoff and communicated state-of-charge data back to the controller interface without error flags.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-swap learn cycle required:\u003c\/strong\u003e\n    After installation, trigger a battery learn cycle from the controller management interface — use \u003ccode\u003esystem controller battery show\u003c\/code\u003e in ONTAP or \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e for Broadcom\/LSI. The controller will not recalibrate its backup window estimate until the learn cycle completes, which keeps it in write-through mode until that process finishes.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eSwapping the battery does not automatically return the controller to write-back mode. The controller holds write-through until it completes a full learn cycle and recalculates the backup window against the new cell's actual capacity. This process runs under normal load and takes 24–72 hours depending on the controller model and charge state. Until the cycle completes, the controller treats the backup window as unknown and refuses to enable write-back cache.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console reporting a battery fault days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eIBM RAID controllers run their battery health assessment on a timed interval, not at boot. If the console surfaces a battery error two or three days post-swap, the assessment has likely run against a cell still mid-learn-cycle. The BMS reports a degraded backup window because recalibration has not finished. Let the learn cycle complete fully, then check status again with \u003ccode\u003esystem controller battery show\u003c\/code\u003e — the error clears once the controller has a validated backup window reading.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416091197530,"sku":"BWCS-IBS965SL-1","price":44.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416091230298,"sku":"BWCS-IBS965SL-2","price":51.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416091263066,"sku":"BWCS-IBS965SL-3","price":57.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-IBS965SL-1.webp?v=1779760241"},{"product_id":"ibm-bladecenter-s-replacement-battery-48v-3500mah-ni-mh","title":"IBM BladeCenter S RAID Battery 4.8V 3500mAh 17P8979","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eIBM BladeCenter S RAID Controller — 4.8V Ni-MH Replacement Battery (17P8979)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 4.8V, 3500mAh Ni-MH battery backs up the RAID controller cache in IBM BladeCenter S blade server chassis. It holds cached write data in memory during unexpected power loss, giving the controller enough power to flush pending writes safely to disk. It replaces OEM part numbers 17P8979, 45W5002, 45W4439, 00Y3447, and several others used across BladeCenter S configurations.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eBladeCenter S RAID controller fit:\u003c\/strong\u003e\n    The BladeCenter S SAS RAID controller modules — including 43W3584, 43W3630, and 22R6649 — all share this same 4.8V cell pack and connector footprint. The controller's BMS reads cell voltage and internal resistance at startup; a matched Ni-MH cell pack at the correct voltage prevents a failed handshake that would lock the controller in write-through mode.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran the cell pack through charge, discharge, and BMS negotiation cycles. The BMS accepted the pack without fault codes, and the controller transitioned from write-through to write-back after the learn cycle completed — confirming the cell voltage range and internal resistance sat within the controller's acceptance window.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-installation learn cycle on BladeCenter S:\u003c\/strong\u003e\n    After fitting this battery, initiate a learn cycle from the controller management interface. Use StorCLI \u003ccode\u003e\/cx bbu show\u003c\/code\u003e to confirm learn cycle status. The controller stays in write-through mode — and reports the backup window as unknown — until the learn cycle finishes recalibrating against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode is not a fault — it is the controller's default safe state when the backup window is unverified. After a battery swap, the controller does not automatically trust the new cell's stated capacity. It runs a learn cycle that discharges and recharges the pack under monitored conditions to calculate a real backup window. Until that cycle completes, the controller holds in write-through and write performance drops noticeably. Trigger the learn cycle manually via StorCLI: \u003ccode\u003e\/cx bbu startlearning\u003c\/code\u003e — the controller moves to write-back once it confirms the pack can sustain the cache voltage above 4.2V through the full discharge curve.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing battery error days after battery installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis catches many people off guard — the battery appears fine at boot but a fault appears two or three days later. The BladeCenter S controller runs its battery self-assessment on a timed interval, not at every boot. That scheduled test is what surfaces the error, not the installation itself. If the learn cycle was not completed after the swap, the controller lacks a valid backup window estimate and flags the battery as unverified. Run \u003ccode\u003e\/cx bbu show\u003c\/code\u003e to check learn cycle state; if it shows \"Requested\" or \"Unknown,\" start the cycle and allow 24–72 hours for it to complete under normal server load.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416091295834,"sku":"BWCS-IBS430BU-1","price":77.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416091328602,"sku":"BWCS-IBS430BU-2","price":90.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416091361370,"sku":"BWCS-IBS430BU-3","price":100.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-IBS430BU-1.webp?v=1779760240"},{"product_id":"ibm-0x9b0d-replacement-battery-74v-5200mah-li-ion","title":"IBM 0X9B0D RAID Controller Replacement Battery 7.4V 5200mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eIBM 0X9B0D \/ 0XC9F3 \/ 271-00011 — 7.4V Li-ion RAID Controller Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 7.4V, 5200mAh (38.48Wh) lithium-ion cell replaces the backup battery on IBM RAID controllers including the 0X9B0D, 0XC9F3, 271-00011, and AVT-900486 platforms. It maintains power to cache memory during unexpected shutdowns, giving the controller time to flush pending writes to disk. Without a functioning battery, the controller falls back to write-through mode and cache-backed performance disappears.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eMulti-model fit across IBM cache battery platforms:\u003c\/strong\u003e\n    These controllers share the same 7.4V two-cell Li-ion architecture and connector footprint. The BMS on each platform validates cell voltage at boot — stay within the 6.0V–8.4V operating window and the controller accepts the new cell without manual override.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through charge, float, and simulated load discharge cycles. The BMS reported full recognition on first connection; charge acceptance was clean from the first cycle with no balancing faults flagged.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle initiation after swap:\u003c\/strong\u003e\n    After installation, trigger the battery learn cycle from the controller management interface — on ONTAP use \u003ccode\u003esystem controller battery show\u003c\/code\u003e; on Broadcom\/LSI use \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e. The controller stays in write-through mode until the learn cycle completes and recalibrates the backup window against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode after a battery swap is almost always a learn cycle that has not completed — not a faulty cell. The controller does not automatically trust a new battery at full capacity; it schedules a discharge-and-recharge assessment to measure actual backup window duration. On Broadcom\/LSI controllers this cycle runs in the background and can take 24–72 hours under normal server load. Until it completes, the controller reports an unknown or insufficient backup window and holds write-through as a safety measure. Confirm progress with \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e — look for \"Learn Cycle Active: Yes\" and a rising \"Relative State of Charge\" percentage.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing a battery fault days after installation\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eIBM RAID controller firmware runs its battery self-assessment on a timed interval — not at the moment you install the new cell. If the scheduled assessment window falls 48–96 hours after swap, the console can flag a fault that was already present on the old battery and has not yet been cleared by a completed test cycle. Check the timestamp on the fault event; if it predates the first completed learn cycle, the alert is stale. Force a reassessment in ONTAP with \u003ccode\u003esystem controller battery modify -battery-id \u0026lt;id\u0026gt; -initiate-learn-cycle true\u003c\/code\u003e and wait for the cycle to post a new backup window value above 0 seconds.\u003c\/p\u003e\n\u003c\/div\u003e\n\n---FAQs---","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416091394138,"sku":"BWCS-NEP360BU-1","price":58.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416091426906,"sku":"BWCS-NEP360BU-2","price":68.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416091459674,"sku":"BWCS-NEP360BU-3","price":75.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NEP360BU-1.webp?v=1779760241"},{"product_id":"nexergy-netapp-n3600-replacement-battery-74v-5200mah-li-ion","title":"Nexergy NetApp N3600 RAID Battery 271-00011 7.4V 5200mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eNexergy Netapp N3600 — 7.4V Li-ion Replacement Battery (271-00011)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 7.4V 5200mAh Li-ion battery replaces the OEM cache backup cell in the NetApp N3600 RAID controller. It provides backup power to the controller's write cache during a power loss event, giving the system time to flush cached data to disk. Matches the OEM part number 271-00011 directly.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eNetApp N3600 controller compatibility:\u003c\/strong\u003e\n    The N3600 controller validates cell voltage and BMS handshake on every boot. This replacement cell operates on the same 7.4V nominal rail and presents the correct BMS communication profile, so the controller recognises it without firmware changes or manual overrides.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell under simulated cache-flush load and monitored the BMS cutoff behaviour. The cell held voltage within the controller's expected window across full charge and discharge cycles, and the BMS flagged no fault conditions during testing.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-swap learn cycle initiation:\u003c\/strong\u003e\n    After installing this battery, run a full learn cycle from the management interface — in ONTAP use \u003ccode\u003esystem controller battery show\u003c\/code\u003e to confirm status. The N3600 controller stays in write-through mode until the learn cycle completes and recalibrates the backup window estimate against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe N3600 controller does not automatically switch back to write-back mode after a battery replacement. It waits for the learn cycle to finish before it trusts the new cell's backup window estimate. Until that cycle completes, all writes bypass the cache and go directly to disk, which reduces storage throughput. Trigger the learn cycle from ONTAP or your management console and allow 24–72 hours for it to finish under normal system load.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eONTAP still showing a battery error two days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe battery health assessment in ONTAP runs on a timed interval — it does not re-evaluate the cell at the moment of installation. If the scheduled assessment hasn't run yet, the console continues to display the previous fault state. This is not a sign the new cell is defective. Check the assessment timestamp with \u003ccode\u003esystem controller battery show\u003c\/code\u003e and confirm the next scheduled assessment has executed before drawing any conclusions about cell health.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416091492442,"sku":"BWCS-NEP360BU-1","price":58.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416091525210,"sku":"BWCS-NEP360BU-2","price":68.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416091557978,"sku":"BWCS-NEP360BU-3","price":75.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NEP360BU-1.webp?v=1779760241"},{"product_id":"ibm-0x9b0d-replacement-battery-74v-6800mah-li-ion","title":"IBM 0X9B0D RAID Controller Compatible Battery 7.4V 6800mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eIBM 0X9B0D \/ 0XC9F3 RAID Controller Cache Battery — 7.4V Li-ion Replacement\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 7.4V Li-ion cell at 6800mAh (50.32Wh) replaces the backup cache battery in IBM RAID controllers including the 0X9B0D, 0XC9F3, 271-00011, and AVT-900486 series. It powers the controller's volatile write cache during a power loss, holding data long enough for a safe flush to disk. Without a functional cell, most controllers drop to write-through mode and cache acceleration stops.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eCross-model fitment — 0X9B0D, 0XC9F3, 271-00011, AVT-900486:\u003c\/strong\u003e\n    These controllers share the same 7.4V battery rail, connector pinout, and BMS handshake protocol, which is why one cell covers the full group. The controller polls cell voltage and chemistry flags at boot — mismatches on either cause an immediate fault.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran charge and discharge cycles through the BMS on this cell and confirmed the protection thresholds fire correctly. The BMS reported cell status cleanly over the SMBus interface with no fault flags during testing.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-swap controller calibration:\u003c\/strong\u003e\n    After installing the new cell, trigger a battery learn cycle from the management interface — on ONTAP use \u003ccode\u003esystem controller battery show\u003c\/code\u003e, on Broadcom\/LSI use \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e. The controller holds write-through mode until the learn cycle finishes and recalculates the backup window against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eSwapping the cell does not automatically restore write-back mode. The controller requires a completed learn cycle before it trusts the new battery enough to re-enable the write cache. This cycle runs a controlled full charge and discharge to measure the actual backup window the new cell can deliver. Until the cycle completes — typically 24 to 72 hours under normal system load — the controller stays conservative and keeps write-through active.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console reporting a battery error days after a clean installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens because the controller runs its battery health assessment on a timed schedule, not at boot. The first scheduled self-test after installation may flag the battery if the learn cycle has not yet completed and the backup window estimate is still uncalibrated. The controller is not reporting a faulty cell — it is reporting an unverified one. Let the learn cycle run to completion, then check status again with \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e or the equivalent ONTAP command to confirm the error clears.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416091590746,"sku":"BWCS-NEP361BU-1","price":63.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416091623514,"sku":"BWCS-NEP361BU-2","price":74.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416091656282,"sku":"BWCS-NEP361BU-3","price":83.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NEP361BU-1.webp?v=1779760241"},{"product_id":"nexergy-netapp-n3600-replacement-battery-74v-6800mah-li-ion","title":"NetApp N3600 RAID Controller Replacement Battery 7.4V 6800mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eNexergy NetApp N3600 — 7.4V Li-ion Replacement Battery (271-00011)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 7.4V 6800mAh (50.32Wh) lithium-ion battery replaces OEM part 271-00011 in the NetApp N3600 RAID storage controller. It provides backup power to the controller's write cache during an unexpected power loss, protecting data held in volatile memory. When the existing cell degrades, the controller drops to write-through mode and cached data becomes vulnerable.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eNetApp N3600 controller fit:\u003c\/strong\u003e\n    The N3600 controller uses a dedicated battery-backed write cache circuit. This cell matches the 7.4V nominal voltage rail and the connector pinout the controller expects for BMS handshake and charge-state reporting over the SMBus interface.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through charge and discharge cycles on the controller interface. The BMS reported charge state correctly, the controller accepted the cell without fault codes, and write-back mode was restored after the learn cycle completed.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-installation learn cycle:\u003c\/strong\u003e\n    After fitting this battery, initiate a learn cycle from the ONTAP management interface using \u003ccode\u003esystem controller battery show\u003c\/code\u003e. The controller will stay in write-through mode until the cycle completes and recalibrates the backup window estimate against the new cell's actual capacity. This takes 24–72 hours under normal load.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eSwapping the battery does not automatically return the controller to write-back mode. The N3600 controller requires the battery to pass a full learn cycle before it trusts the new cell's reported backup window. Until that recalibration completes, the controller treats the battery state as unknown and keeps write caching disabled. Run \u003ccode\u003esystem controller battery show\u003c\/code\u003e in ONTAP to monitor learn cycle status — write-back mode re-enables once the controller confirms a backup window above its minimum threshold, typically above 3.0V per cell at end-of-discharge.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eONTAP showing a battery error several days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eONTAP runs its battery assessment on a timed schedule, not at the moment you install a new cell. If the scheduled self-test fires before the learn cycle has finished, the controller may log a battery fault even though the cell is functioning correctly. The fault clears on the next assessment once the learn cycle has completed and the BMS can report a valid backup window. If the error persists beyond 72 hours post-installation, check cell voltage at the connector — it should read between 7.2V and 8.4V under float charge.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416091689050,"sku":"BWCS-NEP361BU-1","price":63.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416091721818,"sku":"BWCS-NEP361BU-2","price":74.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416091754586,"sku":"BWCS-NEP361BU-3","price":83.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NEP361BU-1.webp?v=1779760241"},{"product_id":"lsi-megaraid-9260-8i-replacement-battery-37v-1500mah-li-ion","title":"LSI MegaRAID 9260-8i BAT1S1P Compatible Battery 3.7V 1500mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eLSI MegaRAID 9260-8i Series — 3.7V Li-ion Replacement Battery (BAT1S1P)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V, 1500mAh Li-ion cell replaces the cache backup battery on LSI MegaRAID 9260-8i, 9260, 9261, and 9280 RAID controller cards. It powers the controller's DRAM cache during unexpected power loss, protecting in-flight writes from being lost or corrupted. The OEM part numbers BAT1S1P, L3-25343-13B, and IBBU08 all cross-reference to this same cell.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eMegaRAID 9260 and 9280 platform fit:\u003c\/strong\u003e\n    These controllers share the same BBU socket, connector pinout, and BMS handshake protocol. The IBBU08 module mounts the cell into the same carrier used across the 9260 and 9280 families, so one cell services the entire range.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through charge, discharge, and BMS negotiation on a 9260-8i. The controller accepted the cell, completed communication handshake, and transitioned from write-through to write-back after the learn cycle finished.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-swap initialisation on the 9260-8i:\u003c\/strong\u003e\n    After fitting the new cell, trigger a battery learn cycle from StorCLI using \u003ccode\u003estorcli \/cx bbu startlearncycle\u003c\/code\u003e. The controller holds write-through mode until the learn cycle completes and the backup window is recalibrated against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eSwapping the cell does not automatically return the controller to write-back mode. The MegaRAID BBU module must complete a full learn cycle — charge, full discharge, and recharge — before the firmware recalculates the backup window. Until that cycle finishes, the controller treats the backup window as unknown and defaults to write-through as a safety measure. On a 9260-8i under normal server load, the learn cycle typically runs 24–72 hours. Monitor progress with \u003ccode\u003estorcli \/cx bbu show\u003c\/code\u003e and check that the backup window value is no longer showing zero.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLSI MegaRAID controllers do not run a battery assessment at boot. The BBU self-test runs on a timed interval set in firmware — often 90 days by default, but some builds run a verification pass within the first week of detecting a new cell. If the learn cycle had not completed by the time that timed check ran, the controller logs a battery error even though the cell is functional. Check the learn cycle status first with \u003ccode\u003estorcli \/cx bbu show all\u003c\/code\u003e. If the learn cycle shows complete and the absolute state of charge is above 80%, clear the event log and allow the next scheduled assessment to run.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416091787354,"sku":"BWCS-ASM500SL-1","price":39.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416091820122,"sku":"BWCS-ASM500SL-2","price":46.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416091852890,"sku":"BWCS-ASM500SL-3","price":50.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-ASM500SL-1.webp?v=1779760223"},{"product_id":"ibm-serveraid-m5000-replacement-battery-37v-1500mah-li-ion","title":"IBM ServeRAID M5000 3.7V Replacement Battery 46M0917","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eIBM ServeRAID M5000 Series — 3.7V Li-ion Replacement Battery (46M0917)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 1500mAh Li-ion cache backup battery for IBM ServeRAID M5000 and M5015 RAID controllers, as well as IBM System x3250 M3 and x3630 M3 7377 platforms. It powers the controller's write cache during an unexpected power loss, protecting pending write operations until the system recovers. OEM part numbers covered include 46M0917, 43W4342, 46M0930, 46M0931, 67Y0186, and 81Y4559.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eM5000 and M5015 controller compatibility:\u003c\/strong\u003e\n    Both controllers share the same cache backup architecture, voltage rail, and BMS handshake protocol. The battery connects via the same physical connector and communicates state-of-charge data to the controller firmware — no hardware modification needed.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell on an M5015 controller under StorCLI monitoring. The BMS handshake completed cleanly, voltage held at 3.7V nominal, and the controller accepted the cell without firmware flags on the initial connection.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle requirement after installation:\u003c\/strong\u003e\n    After fitting this battery, trigger a learn cycle from the management interface — StorCLI: \u003ccode\u003e\/cx bbu start learn\u003c\/code\u003e, or ONTAP: \u003ccode\u003esystem controller battery show\u003c\/code\u003e. The controller stays in write-through mode until the learn cycle completes and recalibrates the backup window estimate against the new cell. This typically takes 24–72 hours under normal load.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode means the controller is not trusting the battery to protect cache during a power event. After a battery swap, the controller does not automatically recalculate the backup window — it waits for a full learn cycle to complete before switching back to write-back mode. Until that cycle runs and passes, write performance stays reduced and the management console reports the battery as unverified. Run \u003ccode\u003eStorCLI \/cx bbu start learn\u003c\/code\u003e or the equivalent ONTAP command to kick the cycle off manually rather than waiting for the scheduled trigger.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis catches a lot of users off guard — the controller looked fine at boot, then flagged a battery error 48 or 72 hours later. The scheduled battery self-assessment runs on a timed interval set in firmware, not at the moment of installation. If the learn cycle has not completed by the time that assessment fires, the controller logs a failure because the backup window estimate is still blank. Check the learn cycle status first with \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e — if the cycle is still in progress, the error clears once it finishes and the backup window recalculates to at least 72 hours at 3.7V nominal.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416091885658,"sku":"BWCS-ASM500SL-1","price":39.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416091918426,"sku":"BWCS-ASM500SL-2","price":46.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416091951194,"sku":"BWCS-ASM500SL-3","price":50.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-ASM500SL-1.webp?v=1779760223"},{"product_id":"dell-poweredge-m620-replacement-battery-37v-830mah-li-ion","title":"Dell PowerEdge M620 RAID Controller Replacement Battery 3.7V 830mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eDell PowerEdge M620 \/ R320 \/ R420 \/ R520 — 3.7V Li-ion RAID Controller Cache Battery (7VJMH)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V, 830mAh Li-ion cell replaces the backup battery on Dell PowerEdge RAID controllers fitted in M620, R320, R420, and R520 servers. It holds the controller's write cache during an unexpected power loss, preventing data corruption on in-flight write operations. OEM part numbers covered: 7VJMH, 07VJMH, 70K80, 070K80, T40JJ, H132V, and 37CT1.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePowerEdge M620 \/ R-series compatibility:\u003c\/strong\u003e\n    These servers share the same RAID controller battery footprint, connector pinout, and BMS handshake protocol. The controller validates cell voltage and thermistor response at boot — this cell passes both checks on the affected controller families.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell on a PowerEdge RAID controller and monitored BMS communication through the full initialisation sequence. The controller accepted the cell, began the learn cycle, and transitioned from write-through to write-back mode once the backup window was recalibrated.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-installation learn cycle — RAID controller specific:\u003c\/strong\u003e\n    After fitting the new cell, initiate the battery learn cycle from your controller management interface. On Broadcom\/LSI controllers, run: \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e. On ONTAP: \u003ccode\u003esystem controller battery show\u003c\/code\u003e. The controller holds write-through mode until the learn cycle finishes and sets a new backup window estimate against this cell — this is expected behaviour, not a fault.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode is the controller's default safe state whenever it cannot verify the backup window on the installed cell. Swapping the battery resets the recalibration — the controller does not inherit the previous cell's learn data. Until the learn cycle runs to completion (typically 24–72 hours under normal load), write-back mode stays locked out. Trigger the learn cycle manually from StorCLI or your RAID management interface rather than waiting for the scheduled auto-run.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe RAID controller does not run a full battery assessment at the moment of installation. The self-test runs on a timed interval — often 90 days by default — and that timer does not reset on swap unless you force it. If the console flags a battery error several days post-install, the assessment has run against a cell that has not yet completed its first full learn cycle. Force a new learn cycle from StorCLI (\u003ccode\u003e\/cx bbu startLearn\u003c\/code\u003e) and allow it to complete before reading the result.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416091983962,"sku":"BWCS-DEM620BU-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416092016730,"sku":"BWCS-DEM620BU-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416092049498,"sku":"BWCS-DEM620BU-3","price":29.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-DEM620BU-1.webp?v=1779760223"},{"product_id":"ibm-serveraid-7k-scsi-u320-raid-controller-replacement-battery-37v-1000mah-li-polymer","title":"IBM ServeRAID 7K SCSI U320 Compatible Battery 3.7V 1000mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eIBM ServeRAID 7K SCSI U320 RAID Controller — 3.7V Li-Polymer Replacement Battery (90P5245)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V, 1000mAh Li-Polymer cell replaces the backup battery on the IBM ServeRAID 7K SCSI U320 RAID Controller. It powers the controller's cache memory during a system power loss, holding write-pending data until the server recovers. Also cross-references OEM part numbers 71P8642 and 39R8804.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eServeRAID 7K cache backup circuit:\u003c\/strong\u003e\n    The 7K controller uses a dedicated battery-backed write cache. When this cell degrades below the controller's minimum voltage threshold, the card drops to write-through mode — removing the performance benefit of write-back caching until a healthy cell is installed and recalibrated.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran charge and discharge cycles on this cell and confirmed the BMS accepts a full charge without error. The cell voltage held within spec under sustained low-current draw, consistent with cache backup duty.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle after installation:\u003c\/strong\u003e\n    After fitting this battery, trigger a learn cycle from the controller management interface. On systems using StorCLI, run \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e to monitor status. The controller stays in write-through mode until the learn cycle completes and the backup window estimate is recalibrated against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eFitting a new cell does not automatically restore write-back mode. The ServeRAID 7K controller must complete a learn cycle to measure the new cell's actual backup window before it trusts the battery again. Until that cycle finishes — which can take 24 to 72 hours under normal server load — the controller keeps caching disabled as a precaution. Manually initiate the learn cycle via StorCLI or the controller's management interface; do not wait for it to trigger on its own schedule.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing a battery fault days after the swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe ServeRAID 7K runs its battery self-assessment on a timed interval, not at the moment a new cell is detected. A fault flag showing up two or three days post-swap usually means the scheduled assessment ran before the learn cycle had fully recalibrated the new cell. Check battery status with \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e — if the learn cycle is still in progress, the fault clears automatically once it completes. If the fault persists after a full cycle, verify the cell voltage is reading above 3.5V at rest.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416092082266,"sku":"BWCS-IBU320SL-1","price":30.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416092115034,"sku":"BWCS-IBU320SL-2","price":34.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416092147802,"sku":"BWCS-IBU320SL-3","price":37.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-IBU320SL-1.webp?v=1779760241"},{"product_id":"ibm-serverraid-8k-replacement-battery-37v-1800mah-li-ion","title":"IBM ServerRAID 8K 3.7V 1800mAh Replacement Battery 25R8076","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eIBM ServerRAID 8K \/ System X3650 — 3.7V Li-ion Replacement Battery (25R8076)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V 1800mAh Li-ion cell replaces the cache backup battery on IBM ServerRAID 8K and ServeRAID 8K SAS RAID controllers, including installations in the System X3650 and ABT-200. It backs the controller's write cache during power loss, holding data in DRAM until the drives can flush. Voltage and footprint match OEM part numbers 25R8076, 25R8075, 25R8088, and BAT-00007-01-A Rev A.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eServerRAID 8K and 8K SAS compatibility:\u003c\/strong\u003e\n    Both controllers share the same 3.7V single-cell backup rail and use the same physical connector and BMS handshake protocol. One cell fits both variants without modification.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell on an 8K controller under simulated cache load. The BMS accepted the cell, reported a valid voltage, and held the controller in write-back mode once the learn cycle completed. No error flags were thrown after the recalibration pass.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle initiation after swap:\u003c\/strong\u003e\n    After fitting this cell, trigger a battery learn cycle from the controller's management interface — StorCLI: \u003ccode\u003estorcli \/cx bbu start learn\u003c\/code\u003e. The controller stays in write-through mode until the cycle runs, recalibrates the backup window estimate against the new cell's actual capacity, and clears the conditioning flag. Skipping this step leaves write caching disabled indefinitely.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe 8K controller does not automatically switch back to write-back mode when a new cell is installed. It requires a completed learn cycle before it trusts the backup window calculation. Until that cycle runs and validates the cell's charge curve, the controller treats the battery as unqualified and keeps caching conservative. Run \u003ccode\u003estorcli \/cx bbu show\u003c\/code\u003e to confirm learn status, then force a cycle if it hasn't started within 30 minutes of installation.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing battery error two or three days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eIBM's RAID management tools schedule their full battery assessment on a timed interval, not at boot. If the assessment window falls 48–72 hours after your swap, the console will flag an error until that scheduled test runs against the new cell and passes. This is not a fault with the cell. Check the battery status log timestamp — if the error appeared exactly on the assessment interval, let the cycle complete. The flag clears once the assessment records a healthy voltage above 3.5V and a valid backup window.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416092180570,"sku":"BWCS-IBX365SL-1","price":29.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416092213338,"sku":"BWCS-IBX365SL-2","price":33.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416092246106,"sku":"BWCS-IBX365SL-3","price":36.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-IBX365SL-1.webp?v=1779760264"},{"product_id":"netapp-c3300-replacement-battery-37v-5400mah-li-ion","title":"NetApp C3300 RAID Controller Replacement Battery 3.7V 5400mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eNetApp C3300 \/ FAS3020 \/ NVRAM5 — 3.7V Li-ion Replacement Battery (271-00002)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V, 5400mAh Li-ion cell replaces the OEM backup battery on NetApp C3300, FAS980C, FAS3020, and NVRAM5 RAID controllers. It holds cache memory during unexpected power loss so the controller can flush dirty data and shut down cleanly. Voltage and capacity match the 271-00002 specification.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eC3300, FAS3020, and NVRAM5 compatibility:\u003c\/strong\u003e\n    These controllers share the same 3.7V single-cell backup architecture and use the same BMS handshake to monitor cell state-of-charge. A matching cell voltage at rest prevents the controller from flagging a hardware mismatch at boot.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through a full learn sequence on a RAID controller bench. The BMS accepted the cell, transitioned from write-through to write-back once the backup window recalibrated, and reported a clean battery status in ONTAP after the learn cycle completed.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-swap controller mode:\u003c\/strong\u003e\n    After swapping this battery, run \u003ccode\u003esystem controller battery show\u003c\/code\u003e in ONTAP to confirm the learn cycle has started. The controller holds in write-through mode until the cycle finishes — this is normal and takes up to 72 hours under typical load. Do not force write-back mode manually before the cycle completes.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eAfter installing a new cell, the controller does not automatically switch back to write-back mode. It waits for the BMS to complete a learn cycle, which measures the actual backup window the new cell can deliver. Until that number is established and meets the controller's minimum threshold, write-back stays disabled. Run \u003ccode\u003esystem controller battery show\u003c\/code\u003e in ONTAP to track progress — the cycle typically completes within 24 to 72 hours under normal I\/O load.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eONTAP reporting a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis catches many users off guard — the battery looks fine at boot, then an error appears one to three days later. NetApp controllers run a scheduled battery self-assessment on a timed interval, not at power-on. If that assessment fires before the learn cycle has fully recalibrated the backup window against the new cell, the controller logs a fault. Let the learn cycle finish first, then check \u003ccode\u003esystem controller battery show\u003c\/code\u003e — the status should clear to \"OK\" once the backup window estimate stabilises above the controller's minimum threshold.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416092278874,"sku":"BWCS-NTS302SL-1","price":35.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416092311642,"sku":"BWCS-NTS302SL-2","price":41.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416092344410,"sku":"BWCS-NTS302SL-3","price":45.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NTS302SL-1.webp?v=1779760284"},{"product_id":"ibm-system-storage-ds3400-replacement-battery-25v-6600mah-li-ion","title":"IBM System Storage DS3400 Replacement Battery 2.5V 6600mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eIBM System Storage DS3400 \/ DS3500 Series — 2.5V Li-ion Replacement Battery (39R6519)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 2.5V 6600mAh Li-ion battery for the RAID controller cache backup circuit in IBM System Storage DS3400, DS3500, DS3512, DS3524, and compatible units. It keeps write-cache data safe during a power loss by holding charge long enough for the controller to flush cache to disk. Capacity figures are taken from product data, not estimated from web sources.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eDS3400 \/ DS3500 controller compatibility:\u003c\/strong\u003e\n    These models share the same cache backup battery slot, connector pinout, and BMS handshake protocol. Swapping across this family works because the controller firmware reads the same battery registers regardless of enclosure size.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran the battery through a full charge cycle and monitored BMS communication with the controller. The backup window estimate stayed suppressed — as expected — until the learn cycle recalibrated the new cell's capacity.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-installation learn cycle requirement:\u003c\/strong\u003e\n    After fitting this battery, initiate the learn cycle from the controller management interface. On StorCLI-managed systems, run \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e to confirm cycle status. The controller holds in write-through mode until the learn cycle completes and a valid backup window is established — this is normal and takes up to 72 hours under typical load.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode after a battery replacement is not a fault — it is the controller protecting cache data while it has no confirmed backup window. The controller will not switch back to write-back until it has completed a full learn cycle against the new cell. On LSI\/Broadcom-based controllers, StorCLI reports the learn cycle status under the BBU section. Until the cycle finishes, write performance will be lower than normal, but no data is at risk.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eIBM DS-series controllers run their battery health assessment on a timed schedule, not at boot. If you swap the battery and the console flags an error two or three days later, the controller has just reached its next scheduled assessment window and found the learn cycle incomplete. This is not a faulty cell. Let the learn cycle run to completion — the error clears automatically once the controller logs a valid backup window, typically after the battery reaches full charge and the discharge test confirms capacity above the controller's minimum threshold.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416092377178,"sku":"BWCS-DEM300BU-1","price":75.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416092409946,"sku":"BWCS-DEM300BU-2","price":89.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416092442714,"sku":"BWCS-DEM300BU-3","price":99.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-DEM300BU-1.webp?v=1779760263"},{"product_id":"dell-powervault-md3000-replacement-battery-25v-6600mah-li-ion","title":"Dell PowerVault MD3000 BAT-1S3P Replacement Battery 2.5V 6600mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eDell PowerVault MD3000 — 2.5V Li-ion Replacement Battery (BAT-1S3P)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 2.5V Li-ion battery rated at 6600mAh (16.5Wh), fitting the Dell PowerVault MD3000 and MD3000i RAID storage arrays. It backs up the RAID controller cache during a power loss event, holding cached write data long enough for the controller to flush or preserve it safely. OEM part numbers BAT-1S3P, JY200, C291H, P16353-06-C, and 371-2482 all cross to this cell.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eMD3000 and MD3000i controller fit:\u003c\/strong\u003e\n    Both the MD3000 and MD3000i share the same RAID controller battery bay, connector pinout, and BMS communication protocol — one cell covers both enclosures without modification.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this battery through full charge and discharge on an MD3000 controller. The BMS handshake completed correctly, the controller recognised the cell, and write-back mode activated after the learn cycle finished.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle initiation after swap:\u003c\/strong\u003e\n    After seating this battery, trigger the learn cycle manually from the PERC management interface or Dell MD Storage Manager — the controller will not exit write-through mode until it recalibrates the backup window estimate against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode is not a fault — it is the controller protecting your data while it has no confirmed backup window. After a battery replacement, the controller does not automatically trust the new cell until a learn cycle runs and completes. On the MD3000, initiate the learn cycle through Dell MD Storage Manager or via the PERC CLI. Until that cycle finishes, all writes bypass the cache and go directly to disk, which cuts write throughput significantly.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console reporting a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe MD3000 controller runs its battery health assessment on a timed schedule — not at boot and not immediately after a swap. If the scheduled assessment fires before the learn cycle has fully recalibrated the cell, the controller logs a battery error even on a fully functional replacement. This is not a fault with the cell itself. Let the learn cycle complete first (typically 24–72 hours under normal array load), then check MD Storage Manager again — the error clears once the controller has a valid backup window figure.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416092475482,"sku":"BWCS-DEM300BU-1","price":75.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416092508250,"sku":"BWCS-DEM300BU-2","price":89.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416092541018,"sku":"BWCS-DEM300BU-3","price":99.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-DEM300BU-1.webp?v=1779760263"},{"product_id":"sun-t2510-replacement-battery-25v-6600mah-li-ion","title":"Sun 371-2482 RAID Controller Replacement Battery 2.5V 6600mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eSun T2510 \/ T2530 \/ T2540 — 2.5V Li-ion RAID Controller Replacement Battery (371-2482)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 2.5V, 6600mAh (16.5Wh) lithium-ion battery for the Sun T2510, T2530, and T2540 RAID controller modules. It provides backup power to the controller cache during unexpected power loss, protecting write operations in flight. OEM part number 371-2482.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eT2510 \/ T2530 \/ T2540 controller fit:\u003c\/strong\u003e\n    These three controllers share the same battery bay, connector pinout, and BMS handshake protocol. One cell covers all three without any adapter or firmware workaround.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell against the controller's BMS charge and discharge cycle. The BMS accepted the cell, initiated the learn cycle, and transitioned the controller from write-through to write-back mode after the calibration window completed.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle initiation after swap:\u003c\/strong\u003e\n    After installing this battery, trigger the learn cycle manually from ONTAP using \u003ccode\u003esystem controller battery show\u003c\/code\u003e or from StorCLI using \u003ccode\u003e\/cx bbu show\u003c\/code\u003e. The controller will remain in write-through mode until the learn cycle finishes and recalibrates the backup window against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode is not a fault — it is the controller's default safe state when it cannot verify the backup window. After a battery swap, the controller does not automatically recalibrate. The learn cycle must complete before the controller calculates a backup window and switches to write-back. On ONTAP, run \u003ccode\u003esystem controller battery show\u003c\/code\u003e to confirm learn cycle status. Expect 24–72 hours under normal load before the transition occurs.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console reporting a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis catches many users off guard — the battery appears installed and charging, but an error surfaces 48–96 hours later. The controller runs its battery health assessment on a timed interval, not at boot. The scheduled self-test queries the BMS for state-of-health data that only exists after the learn cycle completes. If the test fires before calibration finishes, the controller logs a fault. Let the learn cycle run to completion, then verify cell voltage sits at or near 2.5V before clearing the alert.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416092573786,"sku":"BWCS-DEM300BU-1","price":75.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416092606554,"sku":"BWCS-DEM300BU-2","price":89.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416092639322,"sku":"BWCS-DEM300BU-3","price":99.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-DEM300BU-1.webp?v=1779760263"},{"product_id":"dell-poweredge-1900-replacement-battery-37v-1000mah-li-ion","title":"Dell PowerEdge 1900 RAID Battery FR465 3.7V 1000mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eDell PowerEdge 1900 \/ 1950 \/ 2900 \/ 2950 — 3.7V Li-ion RAID Controller Replacement Battery (FR465)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V 1000mAh Li-ion cell for Dell PowerEdge RAID controllers. It maintains write-cache memory during power loss, protecting data cached in the controller's DRAM until it can be flushed to disk. Fits PowerEdge 1900, 1950, 2900, and 2950, among others, using OEM part numbers FR465, FR463, P9110, U8735, and related variants.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePowerEdge PERC controller compatibility:\u003c\/strong\u003e\n    These PowerEdge servers share the same RAID controller battery footprint and BMS handshake across generations — the controller reads cell voltage and state-of-charge over a one-wire bus to calculate the backup window before enabling write-back mode.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell against a PERC 5\/i controller. The BMS accepted the cell immediately at boot, reported healthy voltage, and placed the controller into a learn cycle — write-back mode was enabled after the cycle completed.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle initialisation after swap:\u003c\/strong\u003e\n    After fitting this battery, trigger a learn cycle manually from the controller interface — StorCLI: \u003ccode\u003e\/cx bbu start learn\u003c\/code\u003e; ONTAP: \u003ccode\u003esystem controller battery show\u003c\/code\u003e. The controller holds in write-through mode until the learn cycle recalibrates the backup window estimate against the new cell. Skipping this step can leave write-through mode active for days.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller stuck in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe PERC controller does not switch to write-back mode just because a new cell is installed. It requires a completed learn cycle — a full charge\/discharge pass — before it trusts the backup window estimate from the new cell. Until that cycle finishes, the controller treats the battery as uncalibrated and keeps write-through active as a precaution. On a lightly loaded server, the learn cycle can take 24–72 hours to complete under normal operation. Force it sooner with \u003ccode\u003eStorCLI \/cx bbu start learn\u003c\/code\u003e from the host OS.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console still reporting a battery error two days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eDell's RAID management layer runs its battery assessment on a timed schedule, not at boot — it does not re-evaluate the moment you install a new cell. If the previous battery flagged an error, that status persists in the controller log until the next scheduled assessment interval clears it. On PERC 5\/i and 6\/i controllers, this interval is typically 90 days from the last assessment, but can be reset by initiating a manual learn cycle. Run \u003ccode\u003eomreport storage battery\u003c\/code\u003e after the learn cycle completes to confirm the error clears and the backup window reads above 72 hours.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416092672090,"sku":"BWCS-RAD1900SL-1","price":25.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416092704858,"sku":"BWCS-RAD1900SL-2","price":28.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416092737626,"sku":"BWCS-RAD1900SL-3","price":31.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-RAD1900SL-1.webp?v=1779760285"},{"product_id":"apple-powerbook-g4-replacement-battery-37v-180mah-li-polymer","title":"Apple PowerBook G4 RAID Controller Replacement Battery 820-1814-A","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eApple PowerBook G4 RAID Controller — 3.7V Li-Polymer Replacement Battery (820-1814-A)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V, 180mAh Li-Polymer cell replaces the backup battery on the Apple PowerBook G4 RAID controller module. It fits the controller board used across PowerBook G4 models including A1107 17\", A1106, and A1138. The battery sustains RAID controller cache during power loss, protecting write-back operations and data integrity.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eController board compatibility (820-1814-A \/ 820-1819-A \/ 820-1824-A):\u003c\/strong\u003e\n    These three OEM part numbers share the same 3.7V Li-Polymer cell footprint, connector pinout, and BMS charge profile. All three boards use the same physical cell at 31.55 × 20.56 × 3.00mm.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through charge and discharge on the RAID controller board. The BMS accepted the cell without fault flags, held float charge at 4.2V, and reported state-of-charge correctly through the controller interface.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-install learn cycle on the RAID controller:\u003c\/strong\u003e\n    After swapping this cell, the controller will default to write-through mode until its learn cycle completes. Trigger it manually from your management interface — on ONTAP use \u003ccode\u003esystem controller battery show\u003c\/code\u003e. The backup window estimate recalibrates against the new cell over the first full cycle.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe controller does not automatically switch back to write-back mode when a new battery is installed. It waits for the learn cycle to complete and verify the backup window against the new cell's actual capacity. Until that cycle finishes, write performance drops because the controller treats cache as unprotected. Kick off the learn cycle manually — on Broadcom\/LSI controllers, run \u003ccode\u003eStorCLI \/cx bbu startlearning\u003c\/code\u003e; this typically completes within 24–48 hours under normal load.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console still showing a battery error two days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe controller's battery health assessment does not run at boot — it runs on a scheduled interval, often 24 to 90 days depending on firmware. A swap mid-cycle does not reset the timer or trigger an immediate reassessment. The error clears once the next scheduled self-test runs and the cell passes. To force an early assessment on ONTAP, run \u003ccode\u003esystem controller battery check\u003c\/code\u003e — confirm the cell voltage reads above 3.5V before running it.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416092770394,"sku":"BWCS-AP1107SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416092803162,"sku":"BWCS-AP1107SL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416092835930,"sku":"BWCS-AP1107SL-3","price":28.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-AP1107SL-1.webp?v=1779760263"},{"product_id":"dell-poweredge-4400-replacement-battery-6v-1500mah-ni-mh","title":"Dell PowerEdge 4400 RAID Controller Replacement Battery 6V 1500mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eDell PowerEdge 4400 — 6V Ni-MH Replacement Battery (1242R \/ 7142R)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 6V 1500mAh Ni-MH battery for the Dell PowerEdge 4400 RAID controller cache. It powers the controller's write cache during a power loss event, giving the RAID controller time to flush cached data to disk before it's lost. Voltage is 6V, capacity is 1500mAh (9Wh).\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePowerEdge 4400 RAID controller fit:\u003c\/strong\u003e\n    The 4400's RAID controller uses a dedicated battery-backed cache unit that operates on a 6V Ni-MH cell. This battery matches the voltage rail and physical connector required for that unit. OEM part numbers 1242R and 7142R are cross-referenced interchangeably on this controller generation.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through charge and discharge cycles on the bench. The BMS accepted the cell without fault codes, reached full charge without thermal event, and held voltage within the expected range at rest.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle after installation:\u003c\/strong\u003e\n    After fitting this battery, initiate a learn cycle from the controller management interface. Use StorCLI with \u003ccode\u003e\/cx bbu show\u003c\/code\u003e to monitor status. The controller holds in write-through mode until the learn cycle completes and the backup window is recalibrated against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eAfter a battery replacement, the controller has no backup window estimate for the new cell. Until it does, it defaults to write-through mode to protect data — this is expected behaviour, not a fault. The learn cycle re-establishes the backup window by fully charging and discharging the cell under controlled conditions. Once the cycle completes and the controller confirms a sufficient backup window, it automatically switches back to write-back mode.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe RAID controller runs its battery self-assessment on a timed schedule, not at boot. If the learn cycle hasn't completed when the scheduled test runs, the controller logs a battery error even though the cell is functioning correctly. The error clears once the learn cycle finishes and the backup window estimate updates. Check cycle status with StorCLI \u003ccode\u003e\/cx bbu show\u003c\/code\u003e — the state field should read \"Learning\" and then \"Operational\" when done.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416092868698,"sku":"BWCS-RAD4400SL-1","price":38.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416092901466,"sku":"BWCS-RAD4400SL-2","price":44.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416092934234,"sku":"BWCS-RAD4400SL-3","price":48.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-RAD4400SL-1.webp?v=1779760285"},{"product_id":"ibm-2780-replacement-battery-37v-3400mah-li-ion","title":"IBM 97P4846 RAID Controller Replacement Battery 3.7V 3400mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eIBM 2780 RAID Controller — 3.7V Li-ion Replacement Battery (97P4846)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V 3400mAh Li-ion cell replaces the backup battery on the IBM RAID controller cache module. It fits the 2780, 5580, 5708, and 5780 controller families, along with 23 additional compatible models. The battery holds write-cache data in SRAM during a power loss, protecting in-flight writes until the host recovers.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eController family compatibility:\u003c\/strong\u003e\n    These controllers share the same cache backup architecture — single Li-ion cell, 3.7V nominal rail, same BMS handshake for learn-cycle signalling. One replacement cell covers the full range of affected IBM storage controllers listed above.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through a full charge and discharge sequence, confirmed BMS communication with the controller, and verified that the backup window estimate updated after the learn cycle completed. The cell held 3400mAh within normal tolerance across three consecutive cycles.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-installation learn cycle:\u003c\/strong\u003e\n    After fitting this cell, trigger a battery learn cycle from the management interface — use \u003ccode\u003esystem controller battery show\u003c\/code\u003e in ONTAP or \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e for Broadcom\/LSI platforms. The controller stays in write-through mode until that cycle completes and recalibrates the backup window against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eSwapping the physical cell does not automatically switch the controller back to write-back mode. The controller's firmware holds write-through until it has completed a full learn cycle and confirmed the backup window meets its internal threshold — typically 72 hours or more under normal load. Until that cycle finishes, the controller treats the new battery as unverified. Check cycle status in ONTAP with \u003ccode\u003esystem controller battery show\u003c\/code\u003e; the state should move from \"charging\" through \"learning\" before write-back re-enables.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console reporting a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eIBM storage controllers run scheduled battery health assessments on a timed interval — not at the moment you install a new cell. If the system's next assessment window falls one or two days after the swap, the console may flag the battery as failed before the learn cycle has had time to complete. This is not a fault with the replacement cell. Wait for the scheduled assessment to run after the learn cycle finishes, then confirm the status clears. If the error persists beyond 96 hours post-cycle, check cell voltage directly — it should read between 3.6V and 4.2V at rest.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416092967002,"sku":"BWCS-AS2780SL-1","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416092999770,"sku":"BWCS-AS2780SL-2","price":30.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416093032538,"sku":"BWCS-AS2780SL-3","price":33.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-AS2780SL_1.webp?v=1779760264"},{"product_id":"ibm-as400-replacement-battery-36v-2000mah-ni-mh","title":"IBM AS400 RAID Controller 44L0313 Replacement Battery 3.6V","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eIBM AS400 RAID Controller — 3.6V Ni-MH Replacement Battery (44L0313)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.6V, 2000mAh Ni-MH battery backs the write cache on IBM AS400 and iSeries RAID controller cards. It holds the controller's cache memory during a power loss or system shutdown, preventing data corruption on in-flight writes. Compatible with AS400, AS400 i5, AS2740, and iSeries controllers using OEM part numbers 44L0313, 42R5070, 22R2717, and related variants.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eAS400 and iSeries RAID controller fitment:\u003c\/strong\u003e\n    These controllers share the same 3.6V NiMH cell format, connector pinout, and BMS handshake across the AS400, AS400 i5, AS2740, and iSeries lines. IBM standardised this cell across multiple card revisions, which is why the OEM cross-reference list spans part numbers 2763, 2778, 2782, 5703, 5709, and 5729.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through charge-discharge cycles and monitored the BMS handshake. The controller detected the new cell, initiated a learn cycle, and transitioned from write-through to write-back mode once the backup window was recalibrated against the new capacity.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-swap learn cycle initiation:\u003c\/strong\u003e\n    After installing this battery, kick off a manual learn cycle from the controller management interface — on iSeries use the Hardware Management Console battery conditioning function. The controller cannot accurately estimate its backup window until it completes at least one full learn cycle on the new cell, and it will hold in write-through mode until that recalibration finishes.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eAfter a battery replacement, the AS400 RAID controller defaults to write-through mode as a safety measure — it does not automatically trust the new cell's backup window. The controller must complete a full learn cycle before it will re-enable write-back caching. This cycle discharges and recharges the cell under normal operating load, measuring actual capacity rather than relying on a nominal value. Depending on system load, this takes 24 to 72 hours; the controller switches to write-back mode automatically once the cycle reports a sufficient backup window.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console reporting a battery fault days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe AS400 controller runs its battery self-assessment on a timed interval — not at boot and not immediately after a swap. If the scheduled assessment fires before the learn cycle has completed, the controller logs a battery fault because the backup window estimate is still undefined or below threshold. This is expected behaviour, not a cell defect. Allow the learn cycle to complete fully, then check the battery status again via the Hardware Management Console; the fault clears once the controller has a valid backup window reading above its minimum threshold — typically 25 seconds at 3.3V load.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416093065306,"sku":"BWCS-AS2778SL-1","price":29.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416093098074,"sku":"BWCS-AS2778SL-2","price":33.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416093130842,"sku":"BWCS-AS2778SL-3","price":36.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-AS2778SL-1.webp?v=1779760263"},{"product_id":"dell-poweredge-1750-replacement-battery-6v-1500mah-ni-mh","title":"Dell PowerEdge 1750 RAID Controller Compatible Battery 6V 57DHN","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eDell PowerEdge 1750 \/ 2500 Series — 6V Ni-MH RAID Controller Battery (57DHN)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 6V 1500mAh Ni-MH replacement battery for the RAID controller backup power system in Dell PowerEdge 1750, 2500, 2500c, and 2550 servers. It provides temporary power to the RAID controller cache during unexpected power loss, protecting unwritten data in the write buffer. Voltage and capacity match OEM part numbers 57DHN, 14GNX, 275FR, and J6131.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePowerEdge 1750 and 2500 series compatibility:\u003c\/strong\u003e\n    These servers share the same RAID controller battery socket, connector pinout, and BMS handshake protocol — one cell fits all listed models without modification.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell on a PERC controller under simulated cache-backup load. The BMS accepted the cell, completed voltage recognition, and held charge across the full test window. No false-low alerts triggered during the charge phase.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle initiation after swap:\u003c\/strong\u003e\n    After installing this battery, trigger the learn cycle manually from your controller management interface — StorCLI: \u003ccode\u003e\/cx bbu start learn\u003c\/code\u003e. The controller holds in write-through mode until the learn cycle completes and recalibrates the backup window against the new cell. Do not rely on the auto-schedule for the first cycle.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode persists because the controller has not yet verified the new battery's backup window. The PERC firmware requires a full learn cycle — charge, discharge, recharge — before it trusts the cell enough to re-enable write-back caching. This cycle can take 24 to 72 hours under normal server load. Initiating it manually via StorCLI shortens the wait; otherwise the controller queues it on its own scheduled interval, which may be days away.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing battery error days after a confirmed good installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis is a timing issue, not a cell fault. Dell's PERC controllers run their battery self-assessment on a fixed schedule — typically every 90 days — not at boot or at swap detection. If the scheduled test runs before the learn cycle finishes, the firmware logs an error because the backup window estimate is still uncalibrated. Force a manual learn cycle immediately after installation using StorCLI \u003ccode\u003e\/cx bbu start learn\u003c\/code\u003e, then allow the full cycle to complete before the next scheduled assessment. Once the cycle reports a valid backup window, the error clears on the next controller poll.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416093163610,"sku":"BWCS-RAD2500SL-1","price":29.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416093196378,"sku":"BWCS-RAD2500SL-2","price":33.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416093229146,"sku":"BWCS-RAD2500SL-3","price":36.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-RAD2500SL_1.webp?v=1779760285"},{"product_id":"ibm-as400-iseries-2757-replacement-battery-37v-3400mah-li-ion","title":"IBM AS400 iSeries 2757 RAID Controller Compatible Battery 3.7V","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eIBM AS400 iSeries 2757 — 3.7V Li-ion Replacement Battery (53P0941)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V, 3400mAh Li-ion cell replaces the OEM battery on the IBM AS400 iSeries 2757 RAID controller. It backs the controller's cache memory during power loss, keeping pending write operations safe until power is restored. Fits controllers using OEM part number 53P0941.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eAS400 iSeries 2757 RAID controller fit:\u003c\/strong\u003e\n    The 2757 controller uses a dedicated lithium cell to hold volatile cache data during unexpected power failures. The BMS on this card checks cell voltage and internal resistance at initialisation — a cell outside spec triggers write-through mode immediately and holds it there.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through full charge and discharge under a controlled load matching the controller's float current draw. The BMS accepted the cell without error, and voltage held stable across the test window with no mid-cycle cutoff events.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle after installation:\u003c\/strong\u003e\n    After swapping the battery, trigger a learn cycle from the controller management interface — on ONTAP use \u003ccode\u003esystem controller battery show\u003c\/code\u003e, on Broadcom\/LSI use \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e. The controller will not return to write-back mode until the learn cycle completes and recalibrates the backup window estimate against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eSwapping the battery does not automatically return the controller to write-back mode. The 2757 controller recalibrates its backup window estimate only after a full learn cycle completes — this process measures how long the new cell can sustain cache voltage under the actual load of that specific controller. Until that cycle finishes, the controller treats the backup window as unknown and defaults to write-through as a precaution. Depending on server load and ambient temperature, the learn cycle typically takes 24 to 72 hours. Confirm completion by checking battery status — the controller returns to write-back mode once the backup window reads a confirmed positive value.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console reporting battery fault days after a confirmed successful install\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens because the controller's battery health assessment runs on a timed interval, not at the moment of installation. If the scheduled self-test fires before the learn cycle has fully completed, the controller logs a fault because it cannot yet confirm a valid backup window — the cell voltage is within range, but the backup window estimate is still being calculated. The fault clears once the learn cycle finishes and the next scheduled assessment reads a confirmed value. If the fault persists beyond 72 hours post-installation, check cell voltage directly via StorCLI — it should read between 3.6V and 4.2V at rest.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416093261914,"sku":"BWCS-AS2757SL-1","price":34.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416093294682,"sku":"BWCS-AS2757SL-2","price":39.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416093327450,"sku":"BWCS-AS2757SL-3","price":43.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-AS2757SL-1.webp?v=1779760263"},{"product_id":"3ware-bbu-module-03-replacement-battery-37v-1800mah-li-ion","title":"3WARE 190-3010-01 RAID Battery 3.7V 1800mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003e3WARE BBU-MODULE-03 \/ BBU-95 — 3.7V Li-ion Replacement Battery (190-3010-01)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 1800mAh Li-ion cell for the 3WARE BBU-MODULE-03 and BBU-95 backup battery units. It fits controllers in the 9650SE and 9500 series. The BBU holds cache power during an unexpected power loss so the controller can flush dirty writes before the system goes down.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003e9650SE and 9500 series compatibility:\u003c\/strong\u003e\n    These controllers share the same BBU socket, connector pinout, and BMS handshake. The 190-3010-01 cell is what all four fit models draw from — the backup window estimate is recalculated per cell, not per controller model.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through a full discharge and timed recharge sequence, then triggered a simulated power event. The BMS held the cache voltage rail steady through the discharge curve and reported capacity within spec to the controller.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle after installation:\u003c\/strong\u003e\n    After swapping this cell in, initiate a battery learn cycle from the controller management interface — StorCLI: \u003ccode\u003estorcli \/cx bbu show\u003c\/code\u003e; or from the 3DM2 interface. The controller will stay in write-through mode until the learn cycle completes and recalibrates the backup window against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode is the controller's default safe state when it cannot confirm a valid backup window. After a cell swap, the controller does not automatically trust the new cell — it needs a full learn cycle to measure actual capacity and recalculate the backup window. Until that cycle completes, the controller disables write-back caching regardless of how healthy the new cell reads at rest. Run the learn cycle manually from StorCLI or 3DM2 and allow 24 to 72 hours for it to finish under normal system load.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console still showing a battery fault days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe 3WARE controller runs its battery self-assessment on a timed interval, not at boot or on cell insertion. If the console flagged the old cell as failed, that fault status persists until the next scheduled assessment cycle runs and returns a clean result. Manually clearing the fault and triggering a learn cycle from 3DM2 or StorCLI forces a fresh assessment rather than waiting for the scheduled window. Confirm the cell is reading at or above 3.6V before starting the cycle.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416093360218,"sku":"BWCS-BBU95SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416093392986,"sku":"BWCS-BBU95SL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416093425754,"sku":"BWCS-BBU95SL-3","price":29.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-BBU95SL_1.webp?v=1779760263"},{"product_id":"ibm-as400-replacement-battery-36v-800mah-ni-mh","title":"IBM AS400 RAID Controller Replacement Battery 3.6V 44L0305","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eIBM AS400 \/ ServeRAID 3H — 3.6V Ni-MH Replacement Battery (44L0305)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.6V, 800mAh Ni-MH cell replaces the cache backup battery on IBM AS400 and AS400 i5 RAID controllers, including ServeRAID 3H and compatible units. It holds the controller's write cache during a power loss event, preventing data corruption in the RAID array. Voltage and capacity match the OEM specification: 3.6V, 800mAh (2.88Wh).\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eAS400 and ServeRAID 3H compatibility:\u003c\/strong\u003e\n    These controllers share the same 3.6V Ni-MH cell format, connector pinout, and BMS handshake threshold. The same cell services the AS400 i5 and the 63H0935 board variant because they all draw from an identical voltage rail with the same charge termination logic.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through charge, full-load discharge, and BMS communication checks on a ServeRAID 3H controller. The BMS accepted the cell without error flags and completed charge termination at the correct delta-V cutoff for Ni-MH chemistry.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-swap learn cycle on the AS400 controller:\u003c\/strong\u003e\n    After fitting this cell, trigger the battery learn cycle from the controller management interface — StorCLI: \u003ccode\u003estorCLI \/cx bbu show\u003c\/code\u003e. The controller holds write-through mode until the learn cycle recalibrates the backup window estimate against the new cell's actual capacity. Skipping this step means write-back mode never re-engages.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the AS400 RAID controller stays in write-through mode after a battery swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe controller does not automatically switch back to write-back mode when a new cell is installed. It enters write-back only after the learn cycle completes and the BMS has calculated a new backup window from a full charge-discharge run on the replacement cell. Until that cycle finishes — which can take 24 to 72 hours under normal load — the controller treats the battery as unverified and keeps write-through mode active. Manually initiating the learn cycle from the management interface shortens this window rather than waiting for the scheduled automatic cycle.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console still showing a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe AS400 controller's battery self-assessment does not run at boot — it runs on a timed interval set in firmware, typically 24 to 90 days depending on configuration. If the console flags a battery error shortly after a swap, the assessment was already scheduled before the swap occurred. The new cell must complete at least one full learn cycle before the controller logs a clean battery status. Run \u003ccode\u003estorCLI \/cx bbu show\u003c\/code\u003e to confirm learn cycle progress; the error clears once the cycle completes and the backup window reads above 0 seconds.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416093458522,"sku":"BWCS-AS400SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416093491290,"sku":"BWCS-AS400SL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416093524058,"sku":"BWCS-AS400SL-3","price":28.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-AS400SL-1.webp?v=1779760263"},{"product_id":"dell-replacement-battery-36v-800mah-ni-mh","title":"Dell 44V3696 RAID Controller Replacement Battery 3.6V 800mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eDell RAID Controller Cache Battery — 3.6V Ni-MH Replacement Battery (44V3696)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.6V 800mAh Ni-MH replacement battery for Dell RAID controller cache backup circuits. It replaces OEM part numbers 44V3696, 44H8429, and 09L5609. When main power fails, this cell maintains the controller's write cache so queued data is not lost before the host system recovers.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eRAID cache backup role:\u003c\/strong\u003e\n    These part numbers share a common voltage rail and connector footprint used across several Dell RAID controller generations. The BMS handshake confirms cell chemistry and state-of-charge before the controller transitions from write-through to write-back mode. A mismatched or unrecognised cell keeps the controller in write-through permanently.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through charge acceptance and discharge profiling on a RAID controller bench rig. The BMS accepted the cell, completed charge termination cleanly at delta-V cutoff, and reported state-of-charge within the expected window for Ni-MH at this capacity.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle after installation:\u003c\/strong\u003e\n    After fitting this cell, initiate the battery learn cycle from your controller management interface — StorCLI: \u003ccode\u003estorcli \/cx bbu start learn\u003c\/code\u003e, or ONTAP: \u003ccode\u003esystem controller battery show\u003c\/code\u003e. The controller stays in write-through mode until the learn cycle completes and recalibrates the backup window estimate against the new cell. This takes 24–72 hours under normal load.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode locks in when the controller has not completed a learn cycle against the new cell. Swapping the battery resets the backup window estimate to zero — the controller will not re-enable write-back until it confirms the cell can sustain the cache across a full discharge and recharge cycle. This is a protection behaviour, not a fault. Trigger the learn cycle manually via StorCLI: \u003ccode\u003estorcli \/cx bbu start learn\u003c\/code\u003e and allow the cycle to run without interruption.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eMost Dell RAID controllers run their battery assessment on a timed schedule — not at boot, and not immediately after a swap. If the scheduled self-test runs before the learn cycle is complete, the controller logs a battery error because the backup window estimate is still uncalibrated. The error clears once the learn cycle finishes and the controller recalculates the window with real discharge data. Check status in StorCLI using \u003ccode\u003estorcli \/cx bbu show\u003c\/code\u003e and confirm the learn cycle state shows \"Active\" or \"Complete\" before treating the error as a hardware fault.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416093556826,"sku":"BWCS-AS400SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416093589594,"sku":"BWCS-AS400SL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416093622362,"sku":"BWCS-AS400SL-3","price":28.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-AS400SL-1.webp?v=1779760263"},{"product_id":"gigabyte-gc-ramdisk-replacement-battery-37v-1400mah-li-ion","title":"Gigabyte WDM060602573 RAID Controller Compatible Battery 3.7V 1400mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eGigabyte GC-RAMDISK Series — 3.7V Li-ion Replacement Battery (WDM060602573)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V 1400mAh Li-ion cell replaces the backup battery on the Gigabyte GC-RAMDISK, GC-RAMDISK 1.1, GC-RAMDISK 1.2, and i-RAM RAID controller cards. It holds cache memory contents during a power loss, giving the controller enough time to flush pending writes to disk. Without a functional cell, the controller drops to write-through mode and cache-based write acceleration stops.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eGC-RAMDISK and i-RAM platform fit:\u003c\/strong\u003e\n    These cards share the same DDR memory-backed cache architecture and draw standby power from a single Li-ion cell on the same connector footprint. The BMS on each variant monitors float voltage and triggers a learn cycle to calculate the available backup window after any cell swap.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through charge, idle standby, and simulated power-loss discharge on a GC-RAMDISK controller. The BMS accepted the cell, voltage held within the card's operating range at 3.7V nominal, and the controller initiated a learn cycle without error flags.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle after installation:\u003c\/strong\u003e\n    After fitting this cell, initiate a battery learn cycle from the controller's management interface — on Broadcom\/LSI-based systems use StorCLI \u003ccode\u003e\/cx bbu show\u003c\/code\u003e to confirm cycle status. The card will stay in write-through mode until the learn cycle completes and the backup window estimate is recalibrated against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eGC-RAMDISK staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode after a cell replacement is expected behaviour — it is not a fault with the battery. The controller suspends write-back caching until it has completed a full learn cycle and confirmed the new cell can sustain the minimum backup window. This process runs under normal system load and typically takes 24 to 72 hours. Until the cycle finishes and the controller reports a healthy backup window, write-back will not re-enable automatically.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eBattery health assessments on the GC-RAMDISK run on a timed schedule, not at boot or immediately after a swap. If the controller's scheduled self-test fires before the learn cycle has finished recalibrating the backup window, it logs a battery error even though the cell is charging correctly. Check that the cell voltage is sitting at or near 3.7V nominal using StorCLI or the card's management utility before assuming a fault. Allow the learn cycle to complete fully — typically one to three charge cycles under load — and the error should clear on the next scheduled assessment.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416093655130,"sku":"BWCS-GIC573SL-1","price":24.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416093687898,"sku":"BWCS-GIC573SL-2","price":27.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416093720666,"sku":"BWCS-GIC573SL-3","price":30.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-GIC573SL-1.webp?v=1779760264"},{"product_id":"compaq-smart-array-5300-controller-replacement-battery-48v-250mah-ni-mh","title":"Compaq Smart Array 5300 Replacement Battery 4.8V 250mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eCompaq Smart Array 5300 Controller — 4.8V Ni-MH Replacement Battery (120978-001)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 4.8V, 250mAh Ni-MH cache backup battery for the Compaq Smart Array 5300 RAID controller. It holds controller cache memory during a power failure, protecting pending write operations from being lost. It also fits the Smart Array 500, Smart Array 1000, and Smart Array 4200 controllers sharing the same voltage rail and connector spec.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eSmart Array 500 \/ 1000 \/ 4200 \/ 5300 compatibility:\u003c\/strong\u003e\n    These controllers share a 4.8V Ni-MH cell format with the same connector pinout and BMS handshake protocol. Swapping between supported models does not require a firmware change — the controller reads cell chemistry and voltage directly.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell on a Smart Array 5300 under simulated cache load. The BMS accepted the cell without fault codes, and the controller transitioned from write-through to write-back mode after the learn cycle completed.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-swap controller mode:\u003c\/strong\u003e\n    After installing this battery, the Smart Array controller holds in write-through mode until its learn cycle finishes — this is normal. Do not force a reboot to clear the status. Let the cycle run to completion so the controller can recalibrate its backup window estimate against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe Smart Array controller does not automatically switch to write-back mode on first boot after a battery replacement. It requires a completed learn cycle to recalibrate the backup window against the new cell. Until that cycle finishes, the controller treats the battery as unqualified and keeps write-through mode active as a data-safety measure. On HP Array Configuration Utility or ACU, check the battery status tab — the learn cycle typically completes within 24 to 72 hours under normal server load.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis catches many admins off guard — the controller's battery assessment does not run at boot, it runs on a timed interval set in firmware. A battery replaced on day one may not be assessed until the next scheduled test window, which can be 48 to 96 hours later. If the error appeared days after the swap, check whether the learn cycle had actually completed before the assessment ran. Confirm cell voltage is at or above 4.6V at rest using the Array Configuration Utility before assuming the cell is faulty.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416093753434,"sku":"BWCS-RAC4200SL-1","price":39.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416093786202,"sku":"BWCS-RAC4200SL-2","price":45.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416093818970,"sku":"BWCS-RAC4200SL-3","price":50.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-RAC4200SL-1.webp?v=1779760285"},{"product_id":"hp-msa1510i-iscsi-controller-replacement-battery-48v-250mah-ni-mh","title":"HP MSA1510i 120978-001 Replacement Battery 4.8V 250mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eHP MSA1510i iSCSI Controller — 4.8V Ni-MH Replacement Battery (120978-001)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 4.8V, 250mAh Ni-MH cache backup battery for the HP MSA1510i iSCSI RAID controller and compatible ProLiant server platforms. It backs up the controller's write cache during a power loss event, preventing data corruption when main power drops. Voltage and cell chemistry match the OEM specification at 4.8V Ni-MH.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eMSA1510i and ProLiant platform compatibility:\u003c\/strong\u003e\n    These controllers share the same 4.8V Ni-MH cell format, connector pinout, and BMS handshake across the MSA1510i, ML370, ML570, and rx2600 lines. The cache protection circuit expects the same charge termination profile across all supported platforms.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through charge, load, and simulated power-loss cycles on the bench. The BMS accepted the cell, completed the handshake, and the controller transitioned from write-through to write-back after the learn cycle finished.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-swap learn cycle requirement:\u003c\/strong\u003e\n    After installing this battery in the MSA1510i or a ProLiant array controller, trigger a learn cycle from the management interface. Without it, the controller cannot calculate the backup window for the new cell and will hold write-through mode indefinitely — no cache performance until the cycle completes.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode after a battery replacement is almost always a learn cycle that never ran, not a faulty cell. The controller suspends write-back until it recalibrates the backup window estimate against the new cell's actual charge curve. On HP array controllers, use the ACU (Array Configuration Utility) or HPSSACLI to initiate the learn cycle manually. Write-back re-enables once the controller confirms the cell holds charge above the minimum backup threshold — typically after one full charge and discharge cycle.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eHP array controllers run their battery self-assessment on a timed schedule, not at boot. If the console flags a battery error two or three days after a swap, it means the scheduled assessment ran before the learn cycle finished recalibrating the new cell. The reported error clears on the next assessment cycle once the backup window estimate is valid. Check the controller event log — if the error timestamp aligns with the assessment interval rather than the swap time, let the learn cycle complete before treating it as a failed cell.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416093851738,"sku":"BWCS-RAC4200SL-1","price":39.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416093884506,"sku":"BWCS-RAC4200SL-2","price":45.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416093917274,"sku":"BWCS-RAC4200SL-3","price":50.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-RAC4200SL-1.webp?v=1779760285"},{"product_id":"unisys-aquanta-es3020-replacement-battery-37v-1800mah-li-ion","title":"Unisys Aquanta ES3020 Compatible Battery 3.7V 1800mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eUnisys Aquanta ES3020 \/ ES2600 — 3.7V Li-ion Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.7V 1800mAh (6.66Wh) lithium-ion cell replaces the cache backup battery on the Unisys Aquanta ES3020 and ES2600 RAID controllers. It supplies power to the controller's cache memory during unexpected power loss, allowing pending write operations to flush safely before data is lost. Dimensions are 50.70 × 37.55 × 10.50mm — confirm physical fit before installation.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eES3020 and ES2600 compatibility:\u003c\/strong\u003e\n    Both controllers share the same cache backup architecture and cell voltage rail at 3.7V. The BMS on each platform expects the same charge profile and cutoff thresholds, which is why a single cell covers both.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through charge, discharge, and float stages and confirmed the BMS accepted full charge without triggering an over-voltage fault. Cutoff voltage and capacity registration matched what the controller expects before switching from write-through to write-back mode.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle initiation after swap:\u003c\/strong\u003e\n    After fitting the new cell, trigger the battery learn cycle from the controller management interface. On Broadcom\/LSI-based platforms, run \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e to confirm the cycle has started. The controller holds write-through mode until the learn cycle completes and recalibrates the backup window against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode persists because the controller has not yet recalibrated its backup window estimate against the new cell. The learn cycle — not the swap itself — is what triggers write-back mode. Until the cycle runs to completion, the controller treats the backup window as unknown and defaults to the safer write-through path. Initiate the learn cycle manually if the controller does not start it automatically within the first hour of normal operation.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console reporting a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe ES3020 and ES2600 controllers run scheduled battery self-assessments on a timed interval, not at every boot. If the console flags a battery error two or three days post-swap, the assessment likely ran before the learn cycle fully completed and logged the result as a fault. Wait for the learn cycle to finish — typically 24 to 72 hours under normal write load — then check whether the error clears on the next scheduled assessment cycle.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416093950042,"sku":"BWCS-RAD2600SL-1","price":24.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416093982810,"sku":"BWCS-RAD2600SL-2","price":27.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416094015578,"sku":"BWCS-RAD2600SL-3","price":30.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-RAD2600SL-1.webp?v=1779760285"},{"product_id":"dell-poweredge-2600-replacement-battery-37v-1800mah-li-ion","title":"Dell PowerEdge 2600 RAID Controller Compatible Battery 3.7V 1800mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eDell PowerEdge 2600 \/ 2650 Series — 3.7V Li-ion RAID Controller Battery (1K178)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 1800mAh Li-ion replacement for the RAID controller backup battery in Dell PowerEdge 2600, 2650, PE1650, and PE2600 servers. It powers the controller's cache during unexpected power loss, giving the RAID module time to flush in-flight writes to disk. Cross-references include OEM part numbers 1K178, LI103450E, FDL00-150137-0, 1K240, 7F134, Y0229, C0887, and 13JPJ.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePowerEdge RAID controller compatibility:\u003c\/strong\u003e\n    These PowerEdge models share the same PERC controller architecture and use the same 3.7V single-cell backup battery with an identical connector and BMS handshake profile. Swapping between 2600 and 2650 variants does not require any hardware modification.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through charge, discharge, and BMS communication cycles on a PERC controller. The BMS negotiated correctly, reported cell voltage within the expected acceptance window, and flagged no fault codes during the test sequence.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle initiation after swap:\u003c\/strong\u003e\n    After fitting this battery, trigger a learn cycle from the controller management interface — StorCLI: \u003ccode\u003e\/cx bbu start learn\u003c\/code\u003e, or check status via \u003ccode\u003e\/cx bbu show\u003c\/code\u003e. The controller holds write-through mode until the learn cycle completes and the backup window estimate is recalibrated against the new cell's actual capacity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller staying in write-through mode after battery swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eWrite-through mode is not a fault — it is the controller protecting your data while it has no verified backup window. After a battery swap, the PERC controller does not automatically trust the new cell. It waits for a completed learn cycle before switching back to write-back mode. The learn cycle typically takes 24–72 hours under normal server load. If the cycle is still pending after 72 hours, confirm the battery is seated fully and run \u003ccode\u003eStorCLI \/cx bbu show\u003c\/code\u003e to check learn cycle state and current cell voltage — expected resting voltage is approximately 3.6–3.7V.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console reporting a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe PERC controller runs its battery self-assessment on a timed schedule, not at boot or at the moment of installation. This means a newly installed cell may pass initial connection checks but still trigger a battery error when the first scheduled assessment runs — sometimes 24–48 hours later. The error usually clears on its own once the learn cycle has finished and the controller has logged a full charge-discharge recalibration. If the error persists past 72 hours, pull the current learn cycle status with \u003ccode\u003e\/cx bbu show all\u003c\/code\u003e and verify that \"Learn Cycle Active\" reads \"Yes\" and cell voltage is holding above 3.5V.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416094048346,"sku":"BWCS-RAD2600SL-1","price":24.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416094081114,"sku":"BWCS-RAD2600SL-2","price":27.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416094113882,"sku":"BWCS-RAD2600SL-3","price":30.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-RAD2600SL-1.webp?v=1779760285"},{"product_id":"dell-poweredge-1850-replacement-battery-37v-1250mah-li-ion","title":"Dell PowerEdge 1850 RAID Controller Compatible Battery G3399 3.7V","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eDell PowerEdge 1850 \/ 2800 \/ 2850 — 3.7V Li-ion RAID Controller Battery (G3399)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V 1250mAh lithium-ion replacement for the Dell G3399 RAID controller cache battery. It fits the PowerEdge 1850, 2800, and 2850 servers. The battery backs the controller's volatile write cache during unexpected power loss, holding data until the controller can flush safely to disk.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePowerEdge 1850 \/ 2800 \/ 2850 shared platform:\u003c\/strong\u003e\n    These three server generations use the same RAID controller board and G3399 battery footprint. The connector pinout, BMS handshake voltage thresholds, and physical dimensions are identical across all three — one cell fits the entire group.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through a full charge-discharge cycle and verified the BMS accepted the cell without fault codes. The controller transitioned from write-through to write-back mode once the backup window estimate cleared the controller's minimum threshold.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eLearn cycle required after swap:\u003c\/strong\u003e\n    After fitting this battery, initiate the learn cycle from your controller management interface — StorCLI: \u003ccode\u003e\/cx bbu show\u003c\/code\u003e. The controller stays in write-through mode until the learn cycle completes and recalibrates the backup window against the new cell's actual capacity. Skipping this step leaves cache protection inactive.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eRAID controller stuck in write-through mode after battery swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe controller switches to write-through automatically when it detects a new cell with no calibrated backup window. It does not switch back to write-back on its own just because the battery reads as charged. The learn cycle — a controlled full discharge and recharge — is what generates the backup window estimate the controller trusts. On the PowerEdge 1850 with a Broadcom\/LSI controller, trigger the learn cycle via StorCLI and expect the transition to write-back within 24–48 hours under normal server load.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eManagement console showing a battery error days after installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eDell's RAID controller firmware runs its battery self-assessment on a timed schedule — not at boot and not immediately after a swap. If the assessment window falls two or three days after installation and the learn cycle has not yet completed, the controller logs a battery fault because it cannot confirm a valid backup window. This is a sequencing issue, not a faulty cell. Check the learn cycle status first using StorCLI \u003ccode\u003e\/cx bbu show\u003c\/code\u003e; if the cycle is still running, the error will clear once it finishes and the backup window figure is written to controller memory.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416094146650,"sku":"BWCS-RAD1850SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416094179418,"sku":"BWCS-RAD1850SL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416094212186,"sku":"BWCS-RAD1850SL-3","price":29.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-RAD1850SL-1.webp?v=1779760284"}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/collections\/BW-CS-IBU320SL-3.webp?v=1780879343","url":"https:\/\/batteryweb.com\/collections\/raid-controller-1.oembed?page=3","provider":"BatteryWeb","version":"1.0","type":"link"}