{"product_id":"hyperdata-8640d-replacement-battery-148v-4400mah-li-ion","title":"Hyperdata 8640D 14.8V Replacement Battery 4400mAh Li-ion","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eHyperdata 8640D Series — 14.8V Li-ion Replacement Battery (442673400015)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 14.8V, 4400mAh (65.12Wh) Li-ion battery replaces the original pack in the Hyperdata 8640D, 8640D4, 8640DH, and 8640SH laptops. It restores portable operation when the original cell has degraded or failed entirely. Voltage and connector match the OEM spec exactly — no adapter or modification needed.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003e8640D family compatibility:\u003c\/strong\u003e\n    The 8640D, 8640D4, 8640DH, and 8640SH all share the same 14.8V battery bay, connector pinout, and BMS handshake protocol — which is why a single cell covers all four variants without modification.\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 on the 8640D platform. The BMS communicated correctly with the system, reported charge state without fault codes, and held voltage steadily across the discharge curve.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst-cycle calibration after swap:\u003c\/strong\u003e\n    After installing, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on this platform.\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 fitting a new cell\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe 8640D's BIOS reads health data from EEPROM registers inside the battery pack. When a new cell is installed, those registers don't match the learned discharge profile stored from the old cell. The BIOS flags this mismatch as poor health — even though the new cell is physically fine. Running the battery learn cycle (full discharge to hibernate-cutoff, then uninterrupted charge to 100%) forces the BIOS to rewrite its baseline against the new cell's actual chemistry.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eLaptop shutting down at 20–30% shown on the fuel gauge\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis is a voltage cliff problem, not a calibration issue. Under combined CPU and display load, the cell voltage drops faster than the fuel gauge IC can track — the system hits the low-voltage cutoff threshold while the gauge still shows charge remaining. The fuel gauge IC needs two or three full calibration cycles against the new cell before its predictions stabilise. After calibration cycles, the shutdown threshold should align with readings below 10%. If it persists past three cycles, check that the BIOS power profile isn't set to an aggressive low-battery cutoff above 15V.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43410828722266,"sku":"BWCS-MT8630NB-1","price":80.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 2 Year","offer_id":43410828755034,"sku":"BWCS-MT8630NB-2","price":93.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 3 Year","offer_id":43410828787802,"sku":"BWCS-MT8630NB-3","price":104.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-MT8630NB-big.webp?v=1779581286","url":"https:\/\/batteryweb.com\/products\/hyperdata-8640d-replacement-battery-148v-4400mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}