{"product_id":"lg-vs840-replacement-battery-37v-1200mah-li-ion","title":"LG VS840 Replacement Battery BL-44JS 3.7V 1200mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eLG VS840 Lucid Series — 3.7V Li-ion Replacement Battery (BL-44JS)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 1200mAh Li-ion cell that fits the LG VS840, Lucid, Lucid 4G, and Cayman. It replaces OEM part numbers BL-44JS, EAC61838702, BL-A5JN, and EAC61680101. If your original cell has swollen, won't hold a charge, or the phone shuts down unpredictably, this is the direct swap.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eVS840 and Lucid platform fit:\u003c\/strong\u003e\n    The VS840, Lucid, and Cayman share the same battery bay geometry, connector orientation, and voltage rail. All of these models accept the BL-44JS form factor without modification to the housing or contacts.\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 load cycles on the VS840 platform. The BMS accepted the new cell without handshake errors, and the charge IC brought the cell up from a depleted state without triggering thermal cutoff.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first cycle:\u003c\/strong\u003e\n    After fitting this cell, run one full discharge down to automatic shutdown, then charge uninterrupted to 100% before using the phone heavily. This lets the VS840's fuel gauge IC map its coulomb counter to the new cell's actual discharge curve — skipping this step causes the percentage display to drift or jump in the first several days of use.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the VS840 reports the wrong battery percentage after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe VS840's fuel gauge IC stores a charge profile calibrated to the original cell's internal resistance and capacity fade. When a new cell goes in, that stored profile no longer matches the actual discharge curve. The IC will over- or under-report state of charge until it re-learns the new cell. One full discharge-to-shutdown followed by an uninterrupted charge cycle resets the coulomb counter and forces a fresh calibration pass.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eSudden shutdown at 20–30% on the new cell\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the modem or display draws a current spike and the cell voltage drops below the BMS cutoff threshold — even though the OS still shows 20–30% remaining. On the VS840, the fuel gauge hasn't yet mapped the voltage cliff of the new cell, so it doesn't warn the OS in time. The fix is the same calibration cycle: one complete drain to shutdown, then a full charge. After that cycle, the OS receives accurate low-battery warnings before the voltage cliff hits.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405021413466,"sku":"BWCS-LVS840SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43405021446234,"sku":"BWCS-LVS840SL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43405021479002,"sku":"BWCS-LVS840SL-3","price":29.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-LVS840SL-1.webp?v=1779369841","url":"https:\/\/batteryweb.com\/products\/lg-vs840-replacement-battery-37v-1200mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}