{"product_id":"lenovo-thinkpad-k26-replacement-battery-148v-2200mah-li-ion","title":"Lenovo ThinkPad K26 L09M8Y21 Replacement Battery 14.8V","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eLenovo ThinkPad K26 \/ E26 \/ K27 \/ K29 — 14.8V Li-ion Replacement Battery (L09M8Y21)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 14.8V, 2200mAh (32.56Wh) Li-ion replacement battery for the Lenovo ThinkPad K26, E26, K27, and K29 laptops. It matches the original cell format and connector pinout. OEM part numbers L09M8Y21, L09N8Y21, and L09N4B21 all cross-reference to this unit.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eThinkPad K-series and E26 compatibility:\u003c\/strong\u003e\n    These models share the same 14.8V battery bay geometry, connector type, and BMS communication protocol. Swapping between K26, E26, K27, and K29 uses the same cell pack because Lenovo held the voltage rail and SMBus handshake constant across this lineup.\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 K26 and confirmed the BMS negotiated correctly with the system board — charge acceptance started immediately, the fuel gauge IC registered the new cell within two cycles, and no fault codes appeared in the battery status register.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-install calibration on ThinkPad K-series:\u003c\/strong\u003e\n    After fitting this battery, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle. Skipping it leaves the fuel gauge IC working off stale EEPROM data from the old cell, which causes inaccurate state-of-charge readings from the first use.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eThinkPad K26 shutting down at 20–30% charge shown\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the cell voltage drops below the BMS cutoff threshold under combined CPU and display load — even though the OS fuel gauge still shows remaining capacity. The fuel gauge IC is reading state-of-charge from a model built around the old cell's discharge curve. With a new cell installed but no calibration run, the IC misreads the voltage cliff and the system shuts down before the gauge hits zero. Run one full discharge to hibernate-cutoff followed by a full uninterrupted charge. After two complete cycles the fuel gauge IC recalibrates against the new cell's actual curve and the premature shutdown stops.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eBIOS reporting battery health as poor immediately after swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe ThinkPad BIOS reads health data from the battery's EEPROM — not from live cell measurements. When you install a replacement, the EEPROM still carries cycle count and wear data written by the original cell. The BIOS sees that stored history and flags the battery as degraded before the new cell has run a single cycle. This is not a fault with the replacement. To clear it, enter the BIOS power management screen and run the battery learn cycle, or discharge fully to hibernate-cutoff and recharge to 100% twice. After the learn cycle completes, the health indicator updates to reflect the actual new cell state.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43409782931546,"sku":"BWCS-LVK260NB-1","price":99.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 2 Year","offer_id":43409782964314,"sku":"BWCS-LVK260NB-2","price":112.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 3 Year","offer_id":43409782997082,"sku":"BWCS-LVK260NB-3","price":122.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-LVK260NB-1.webp?v=1779580839","url":"https:\/\/batteryweb.com\/products\/lenovo-thinkpad-k26-replacement-battery-148v-2200mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}