{"product_id":"blu-vivo-xi-replacement-battery-385v-2800mah-li-polymer","title":"BLU Vivo XI+ Replacement Battery C796438300P 3.85V 2800mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eBLU Vivo XI+ — 3.85V Li-Polymer Replacement Battery (C796438300P)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.85V, 2800mAh Li-Polymer cell is a direct replacement for the BLU Vivo XI+, Vivo XI Plus, and V0310WW. It restores full power to the processor, display, modem, and all onboard functions. Capacity is 10.78Wh, matching the original cell specification.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eVivo XI+ \/ V0310WW platform fit:\u003c\/strong\u003e\n    All three model designations share the same battery bay geometry, connector pinout, and BMS handshake protocol — one cell covers the full variant range without modification.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through charge and discharge on the Vivo XI+ platform. The BMS accepted charge initiation cleanly, protection thresholds triggered correctly at low voltage, and the fuel gauge IC tracked state-of-charge without erratic jumps after the first full cycle.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst-cycle fuel gauge recalibration:\u003c\/strong\u003e\n    On first use after installation, disable fast charging and complete one full discharge-to-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging introduces error into the coulomb counter baseline.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the Vivo XI+ reports wrong battery percentage after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe Vivo XI+ uses a fuel gauge IC that builds its capacity model from the original cell's discharge curve over time. When a new cell goes in, that learned curve no longer matches the new cell's actual voltage-to-capacity relationship. The result is percentage readings that are off by 10–20% or jump suddenly. One full discharge cycle — from 100% down to automatic shutdown, then a complete charge — forces the IC to remap against the new cell and correct its baseline.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eSudden shutdown at 20–30% remaining on the replacement cell\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the modem or display draws a current spike the cell cannot sustain at that state-of-charge, causing terminal voltage to drop below the BMS cutoff threshold — even though the percentage display still shows capacity remaining. It is a voltage-sag failure, not a capacity failure. The fuel gauge IC has not yet recalibrated, so it reports 25% when the cell is actually near its voltage floor under load. Complete two full discharge-charge cycles at standard rate; if shutdown persists below 3.5V under screen-on load after that, the BMS trip threshold may need a reset by draining the cell fully to auto-shutdown before recharging.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43391896518746,"sku":"BWCS-BLX310SL-1","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43391896551514,"sku":"BWCS-BLX310SL-2","price":30.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43391896584282,"sku":"BWCS-BLX310SL-3","price":33.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-BLX310SL-1.webp?v=1779142595","url":"https:\/\/batteryweb.com\/products\/blu-vivo-xi-replacement-battery-385v-2800mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}