{"product_id":"umi-umidigi-bison-replacement-battery-387v-4800mah-li-polymer","title":"UMIDIGI BISON Replacement Battery 1ICP\/6\/63\/81 3.87V 4800mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eUMI UMIDIGI BISON 2021 — 3.87V Li-Polymer Replacement Battery (1ICP\/6\/63\/81)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 3.87V 4800mAh lithium-polymer cell replaces the original battery in the UMIDIGI BISON (2021). It fits directly into the BISON's battery bay using the OEM part number 1ICP\/6\/63\/81. Dimensions are 77.90 × 63.30 × 5.30mm — match these against your original cell before installing.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eUMIDIGI BISON 2021 fitment:\u003c\/strong\u003e\n    The BISON uses a 3.87V nominal Li-Polymer cell tied to a charge IC that expects a specific charge termination voltage of 4.35V. This replacement matches that voltage ceiling, so the on-board charge IC does not reject the cell or flag a fault during the constant-voltage phase.\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 BISON hardware. The BMS accepted full CC-CV charging without triggering an overcurrent cutoff, and cell voltage held within spec under sustained screen-on and modem load.\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 run one complete discharge-to-charge cycle at standard rate. The fuel gauge IC on the BISON calibrates its coulomb counter against the cell's discharge curve — skipping this step leaves the IC reading from the old cell's data, causing erratic percentage jumps.\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 UMIDIGI BISON after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eA degraded original cell develops high internal impedance, and the fuel gauge IC builds its discharge model around that aged curve. When a fresh low-impedance cell goes in, voltage drops faster under modem and display load than the IC predicts. The IC sees a voltage cliff — cell voltage sags below the cutoff threshold while the reported percentage still reads 20–30%. One full slow-charge cycle forces the coulomb counter to relearn the new cell's actual capacity and discharge rate, eliminating the false cutoff.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eUSB-PD fast charging not activating on the first cycle after replacement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe BISON's charge controller handshakes with the battery BMS before enabling high-current fast charging. On a brand-new cell, the BMS has no charge history logged, and some charge controllers default to trickle or standard charge on the first cycle as a precaution. This is not a fault with the replacement cell. Charge fully once at the standard rate, then reconnect the charger — the fast-charge handshake completes normally once the BMS has one completed cycle recorded.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43391876169818,"sku":"BWCS-UMB202SL-1","price":28.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43391876202586,"sku":"BWCS-UMB202SL-2","price":32.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43391876235354,"sku":"BWCS-UMB202SL-3","price":35.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-UMB202SL-1.webp?v=1779142499","url":"https:\/\/batteryweb.com\/products\/umi-umidigi-bison-replacement-battery-387v-4800mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}