{"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","url":"https:\/\/batteryweb.com\/products\/nexergy-nex900803-replacement-battery-72v-2600mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}