{"product_id":"lenovo-thinkpad-1838-replacement-battery-74v-3200mah-li-polymer","title":"Lenovo ThinkPad 1838 Replacement Battery 42T4963 7.4V 3200mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eLenovo ThinkPad 1838 Series — 7.4V Li-Polymer Replacement Battery (42T4963)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 7.4V, 3200mAh (23.68Wh) lithium-polymer battery replaces the original power cell in the Lenovo ThinkPad 1838 tablet. It fits the ThinkPad 1838, 1838 10.1, 1838-25U, and 1838-22U. OEM part numbers covered include 42T4963, 42T4964, 42T4985, 42T4965, and 42T4966.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eThinkPad 1838 variant coverage:\u003c\/strong\u003e\n    The 1838, 1838 10.1, 1838-25U, and 1838-22U share the same physical cell format, connector pinout, and BMS handshake protocol. One battery 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 ran this cell through charge and discharge cycles on a ThinkPad 1838 unit. The BMS accepted the cell without fault codes, completed a full charge cycle, and the tablet powered on and off cleanly across multiple sessions.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration after swap:\u003c\/strong\u003e\n    After fitting this battery, run the tablet down to automatic shutoff — do not force-power it off. Then charge it uninterrupted to 100%. This gives the fuel gauge IC a clean reference point against the new cell and corrects percentage drift that appears immediately after installation.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eThinkPad 1838 shutting down at 15–25% remaining\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the tablet runs the display at full brightness alongside active Wi-Fi — combined draw pulls the cell voltage down faster than the fuel gauge expects. The BMS reads a voltage threshold that triggers a protection cutoff, but the OS still shows charge remaining. The fix is one full recalibration cycle: discharge to automatic shutoff, then charge to 100% without interruption. After that cycle, the fuel gauge aligns with the actual cell voltage curve and premature shutoffs stop.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eFast charging not available after battery replacement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe ThinkPad 1838 charge controller needs at least one completed charge cycle before it confirms USB-PD negotiation parameters with a new cell. Until that cycle completes, the tablet defaults to standard charge rates as a safety measure. Plug in the tablet and let it charge from low to 100% without unplugging partway. After that first full cycle, fast charge becomes available again on compatible adapters.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43426075148378,"sku":"BWCS-LVP183SL-1","price":71.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43426075181146,"sku":"BWCS-LVP183SL-2","price":84.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43426075213914,"sku":"BWCS-LVP183SL-3","price":93.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-LVP183SL-1.webp?v=1779930339","url":"https:\/\/batteryweb.com\/products\/lenovo-thinkpad-1838-replacement-battery-74v-3200mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}