{"product_id":"issam-smartbook-i-8640-replacement-battery-148v-4400mah-li-ion","title":"ISSAM SmartBook i-8640 14.8V Compatible Battery 442673400015","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eISSAM SmartBook i-8640 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 ISSAM SmartBook i-8640, i-8640C, i-8640D\/M, and 8640L\/S notebooks. It uses the same connector, voltage rail, and BMS communication protocol as the factory cell. Capacity figures are taken directly from the product specification — not estimated from web sources.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eSmartBook i-8640 family compatibility:\u003c\/strong\u003e\n    All four variants in this lineup share the same 14.8V four-cell configuration, connector pinout, and BMS handshake protocol. A single battery covers the full range without adapter or firmware modification.\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 cutoff on the SmartBook platform. The BMS authenticated correctly, reported state-of-charge accurately after two calibration cycles, and triggered low-voltage protection at the expected threshold.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-install calibration on the SmartBook i-8640:\u003c\/strong\u003e\n    After fitting this cell, run one full discharge to hibernate cutoff, then charge uninterrupted to 100% before use. 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 battery health as poor after installing a new cell\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe ISSAM SmartBook BIOS stores battery health data in EEPROM from the previous cell. When a new pack is installed, the BIOS compares live readings against that stored profile and flags a mismatch as poor health. This is a firmware read issue, not a fault with the replacement cell. Running one complete discharge-to-hibernate followed by a full uninterrupted charge forces the BIOS to overwrite the old EEPROM record. After that single learn cycle, the health indicator updates to reflect the new cell correctly.\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 happens when the fuel gauge IC has not yet calibrated against the new cell's chemistry. The gauge was mapped to the old cell's discharge curve, so its percentage estimate diverges from actual cell voltage under CPU and display load. At high draw, the real cell voltage drops below the BMS protection threshold before the gauge reaches zero — triggering an abrupt shutdown. Run two full discharge-to-charge cycles without interruption and the fuel gauge IC will re-map to the new cell; shutdowns should stop once the gauge reads within 5% of actual state-of-charge.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43410829115482,"sku":"BWCS-MT8630NB-1","price":80.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 2 Year","offer_id":43410829148250,"sku":"BWCS-MT8630NB-2","price":93.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 3 Year","offer_id":43410829181018,"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\/issam-smartbook-i-8640-replacement-battery-148v-4400mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}