{"product_id":"dell-latitude-12-5285-replacement-battery-114v-2550mah-li-polymer","title":"Dell Latitude 12 5285 1WND8 Replacement Battery 11.4V 2550mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eDell Latitude 12 5285 — 11.4V Li-Polymer Replacement Battery (1WND8)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is an 11.4V, 2550mAh (29.07Wh) Li-Polymer battery for the Dell Latitude 12 5285 2-in-1 ultrabook. It replaces OEM part number 1WND8 directly. The 5285 uses a slim Li-Polymer cell to stay within its compact chassis — standard Li-ion cylindrical cells do not fit this slot.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eLatitude 5285 platform fit:\u003c\/strong\u003e\n    The 5285 runs an 11.4V three-cell Li-Polymer pack with a specific SMBus connector and BMS handshake. The BIOS authenticates the battery over SMBus before enabling charge. A cell that does not match the expected voltage rail or communication protocol will show as unrecognised immediately on boot.\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 5285 platform. The BMS reported state-of-charge correctly, the BIOS accepted the SMBus handshake without flags, and charge tapered cleanly at full capacity.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst-cycle learn reset on the 5285:\u003c\/strong\u003e\n    After fitting this battery, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. The BIOS battery learn cycle needs this to calibrate the fuel gauge IC against the new cell. Skipping it causes the health warning that appears after every cell swap.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eBIOS reporting poor battery health immediately after installing a new cell\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe Latitude 5285 BIOS reads health data from the cell's EEPROM on every boot. When a new cell is fitted, the EEPROM contains factory default values that do not match the BIOS's stored discharge history. The system flags this mismatch as degraded health — even on a brand-new cell. Running one complete discharge-to-hibernate then an uninterrupted full charge lets the BIOS overwrite the old data and recalculate from the new cell's baseline.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eLaptop shutting down at 20–30% charge shown on screen\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the fuel gauge IC still maps voltage curves from the old, degraded cell. Under combined CPU and display load, the new cell's actual voltage drop looks like a cliff to the old calibration data, and the system cuts power before the gauge reaches 0%. It is a calibration mismatch, not a fault with the new cell. Run two full discharge-to-hibernate and full recharge cycles to reset the fuel gauge — after that, the shutdown point will move back to the correct voltage floor near 10.2V.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43409608540250,"sku":"BWCS-DEL128NB-1","price":57.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43409608573018,"sku":"BWCS-DEL128NB-2","price":67.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43409608605786,"sku":"BWCS-DEL128NB-3","price":74.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-DEL128NB-1.webp?v=1779580170","url":"https:\/\/batteryweb.com\/products\/dell-latitude-12-5285-replacement-battery-114v-2550mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}