{"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","url":"https:\/\/batteryweb.com\/products\/netapp-nex-90089-replacement-battery-72v-5200mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}