{"product_id":"lenovo-thinkpad-x201s-replacement-battery-108v-4400mah-li-ion","title":"Lenovo ThinkPad X201S 10.8V Replacement Battery 42T4534","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eLenovo ThinkPad X201S \/ X201i — 10.8V Li-ion Replacement Battery (42T4534)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 10.8V, 4400mAh (47.52Wh) lithium-ion battery replaces the original cell in the Lenovo ThinkPad X201S and X201i. It matches OEM part numbers 42T4534, 42T4536, 42T4538, and related FRU\/ASM variants. The X201S is a slim business ultraportable — this battery fits its standard 6-cell bay directly.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eX201S and X201i compatibility:\u003c\/strong\u003e\n    Both models share the same 10.8V battery rail, connector pinout, and BMS handshake protocol. The EEPROM data embedded in this cell matches what the ThinkPad EC firmware expects during battery authentication.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell on a ThinkPad X201S under combined CPU and display load. The BMS held charge regulation correctly, passed EC authentication, and did not trigger a false low-voltage cutoff during the test cycle.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst-cycle conditioning on ThinkPad X201S:\u003c\/strong\u003e\n    After installing, run one full discharge to the 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 this cell\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe ThinkPad EC reads EEPROM data from the old cell and compares it against the new one at first boot. When the stored cycle count and capacity values don't match the fresh cell, the firmware flags it as degraded before any real measurement occurs. This is not a fault with the replacement — it's stale data from the previous battery. Running the full discharge-to-hibernate then uninterrupted charge cycle forces the BIOS to rewrite the learn data and clear the warning.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eX201S shutting down abruptly while the fuel gauge still shows 20–30% remaining\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the cell voltage drops sharply under combined CPU and display load — a voltage cliff the fuel gauge IC didn't predict because it was calibrated to the old cell's discharge curve. The gauge IC needs two or three full discharge-to-charge cycles against the new cell before its readings stabilise. Until then, treat any reading below 35% as unreliable. After the third full cycle, the reported percentage at shutdown should align closely with actual cell voltage — around 10.8V at full charge dropping to the 9.0V BMS cutoff floor.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43410822856794,"sku":"BWCS-IBX200NB-1","price":94.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43410822889562,"sku":"BWCS-IBX200NB-2","price":107.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43410822922330,"sku":"BWCS-IBX200NB-3","price":117.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-IBX200NB-1.webp?v=1779581243","url":"https:\/\/batteryweb.com\/products\/lenovo-thinkpad-x201s-replacement-battery-108v-4400mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}