{"product_id":"fitbit-versa-4-replacement-battery-387v-160mah-li-polymer","title":"FitBit Versa 4 Replacement Battery LSS282024P 3.87V 160mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eFitBit Versa 4 — 3.87V Li-Polymer Replacement Battery (LSS282024P)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.87V, 160mAh lithium-polymer cell that fits the FitBit Versa 4 smartwatch. It replaces part number LSS282024P when the original cell has degraded through repeated charge cycles. The battery measures 24.20 × 20.00 × 2.60mm and connects to the Versa 4's flex PCB via the original ribbon connector.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eVersa 4 cell fitment:\u003c\/strong\u003e\n    The Versa 4 uses a compact Li-Polymer pouch cell at 3.87V nominal — a slightly elevated nominal versus standard 3.7V cells. The BMS on this platform expects that voltage profile. Substituting a mismatched cell voltage causes the fuel gauge IC to report incorrect state-of-charge from the first cycle.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through the Versa 4's charge controller and confirmed the BMS accepted the charge profile without triggering an over-voltage cutoff. The fuel gauge re-initialised correctly after a full charge-from-near-zero sequence post-swap.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-swap charge requirement:\u003c\/strong\u003e\n    After fitting this cell, place the Versa 4 on its magnetic charger immediately and charge to 100% before using the watch. The fuel gauge IC on this platform loses its reference point when the cell is removed. Without a full charge cycle from near-zero, the percentage readout will be inaccurate for days.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the Versa 4 fuel gauge shows wrong percentages after a cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe Versa 4 uses a coulomb-counting fuel gauge IC that tracks charge in and out relative to a stored full-charge reference. Removing the battery clears that reference from volatile memory. When a new cell is fitted, the IC has no baseline, so it estimates state-of-charge from open-circuit voltage alone — which is unreliable mid-cycle. Running a complete charge to 100% from a low state lets the IC set a new full-charge reference and restore accurate readings within one or two cycles.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eVersa 4 not pairing to phone after battery replacement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eRemoving the battery terminates the active BLE session between the Versa 4 and the paired phone. The watch does not automatically re-establish that bond on power-up — the phone's Bluetooth stack still holds the old session key, and the two devices talk past each other. On the phone, go to Bluetooth settings, forget the Versa 4 device entry, then re-pair through the Fitbit app as if setting up for the first time. The watch itself needs no reset; removing the stale bond on the phone side is enough.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43416160960602,"sku":"BWCS-FTV400SL-1","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43416160993370,"sku":"BWCS-FTV400SL-2","price":30.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43416161026138,"sku":"BWCS-FTV400SL-3","price":33.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-FTV400SL-1.webp?v=1779760505","url":"https:\/\/batteryweb.com\/products\/fitbit-versa-4-replacement-battery-387v-160mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}