{"product_id":"vivo-x9s-plus-replacement-battery-385v-3950mah-li-polymer","title":"Vivo X9s Plus B-C2 Compatible Battery 3.85V 3950mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eVivo X9s Plus — 3.85V Li-Polymer Replacement Battery (B-C2)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.85V, 3950mAh lithium-polymer cell replaces the original B-C2 battery in the Vivo X9s Plus smartphone. It fits the X9s Plus directly, matching the OEM voltage rail, connector, and physical dimensions (85.05 × 67.60 × 4.10mm). Swap it in when the original cell can no longer hold a charge through a normal day of use.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eX9s Plus platform fit:\u003c\/strong\u003e\n    The X9s Plus uses a dedicated battery bay sized for this exact cell footprint. The B-C2 part number ties this cell to the Vivo X-series BMS handshake — the charge IC on this phone negotiates current limits with the cell's internal protection circuit, so voltage and connector alignment both matter.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through full charge and discharge passes on the X9s Plus. The BMS accepted the cell without triggering an over-voltage or under-voltage cutoff, and the charge IC stepped through trickle, constant-current, and constant-voltage phases cleanly.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration after install:\u003c\/strong\u003e\n    On first use, disable fast charging and run one full discharge down to automatic shutdown, then charge to 100% on a standard 5V charge. This lets the coulomb counter in the fuel gauge IC map its reference curve against 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\"\u003eWhy the X9s Plus reports wrong battery percentage after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe X9s Plus uses a fuel gauge IC that tracks charge state using a learned discharge curve from the original cell. When you install a fresh 3950mAh cell, that stored curve no longer matches the new cell's actual voltage-vs-capacity profile. The IC may show 80% when the cell is at 60%, or drop suddenly from 30% to zero. One full discharge-charge cycle without interruption forces the coulomb counter to relearn the curve against the new cell. After that cycle, percentage readouts stabilise.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eSudden shutdown at 20–30% on the replacement cell\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the cell voltage drops below the BMS cutoff threshold under a high-current load — typically the modem, GPS, or display all drawing at once — even though the fuel gauge still shows charge remaining. A freshly installed cell that has not been through a calibration cycle will have a mismatched reference point, making this cliff worse. Run one uninterrupted discharge to shutdown and a full charge back to 100%. If shutdowns continue past the second cycle, check that the cell connector is fully seated — a partial contact raises internal resistance and causes the same voltage sag under load.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43392060653658,"sku":"BWCS-BYX930XL-1","price":25.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43392060686426,"sku":"BWCS-BYX930XL-2","price":28.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43392060719194,"sku":"BWCS-BYX930XL-3","price":31.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-BYX930XL-1.webp?v=1779143470","url":"https:\/\/batteryweb.com\/products\/vivo-x9s-plus-replacement-battery-385v-3950mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}