{"product_id":"vivo-v15-replacement-battery-385v-3900mah-li-polymer","title":"Vivo V15 B-G2 Replacement Battery 3.85V 3900mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eVivo V15 \/ V1831 — 3.85V Li-Polymer Replacement Battery (B-G2)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.85V, 3900mAh lithium-polymer replacement battery for the Vivo V15 and V1831 smartphones. OEM part number B-G2. It fits directly into these models and restores the phone's ability to hold a full charge when the original cell has degraded or failed.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eV15 and V1831 platform:\u003c\/strong\u003e\n    Both models run the same battery architecture — identical voltage rail, connector pinout, and BMS handshake protocol. A single B-G2 cell covers the full production run of both device designations.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran the B-G2 through full charge and discharge cycles on the V15 platform. The BMS accepted the cell, protection thresholds fired correctly at low voltage, and the charge IC negotiated the expected current without flagging errors.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    Disable fast charging for the first complete discharge-charge cycle after installation. The fuel gauge IC on the V15 is calibrated to the old cell's discharge curve. One full cycle at standard current lets it build an accurate map of the new cell before high-current charging begins.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eSudden shutdown at 20–30% on the V15 after a cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens because the fuel gauge IC still references the discharge curve of the original, degraded cell. When the new cell's voltage drops under modem or screen load, the IC reads a voltage it didn't expect at that state-of-charge and triggers a protective shutdown. The phone isn't faulty — the calibration data is stale. One full discharge to system-off followed by a complete charge cycle rewrites the coulomb counter baseline and stops the early cutoffs.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eUSB fast charge not activating on the first cycle after replacement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eOn the first charge after fitting a new cell, the charge IC may stay in trickle or standard mode rather than stepping up to fast charge. The BMS on a fresh cell needs to confirm cell impedance and temperature are within range before it allows high-current negotiation. This is normal behaviour and not a fault with the battery or charger. Completing one full standard charge cycle is usually enough — fast charge activates automatically from the second cycle onward once the BMS has profiled the cell.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43391904284762,"sku":"BWCS-BYV150SL-1","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43391904317530,"sku":"BWCS-BYV150SL-2","price":29.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43391904350298,"sku":"BWCS-BYV150SL-3","price":32.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-BYV150SL-1.webp?v=1779142595","url":"https:\/\/batteryweb.com\/products\/vivo-v15-replacement-battery-385v-3900mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}