{"product_id":"redmi-6a-replacement-battery-385v-2900mah-li-polymer","title":"Redmi 6A BN37 Replacement Battery 3.85V 2900mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eRedmi 6A — 3.85V Li-Polymer Replacement Battery (BN37)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.85V, 2900mAh Li-Polymer replacement battery for the Redmi 6A smartphone. It carries OEM part number BN37 and fits the M1804C3DH, M1804C3DC, and Redmi 6A Dual SIM TD-LTE variants. Install it when the original cell no longer holds a charge or the phone shuts down unexpectedly under load.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003e6A variant compatibility:\u003c\/strong\u003e\n    The M1804C3DH and M1804C3DC share the same physical cell footprint, connector pinout, and BMS handshake requirements. One BN37 cell covers all listed variants 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 a Redmi 6A unit. The BMS accepted charge at both standard and fast-charge rates after the first full calibration cycle, and protection cutoffs triggered correctly at both ends of the voltage range.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging begins on an uncalibrated cell.\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 Redmi 6A after a cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe Redmi 6A's fuel gauge IC stores a discharge curve calibrated to the original cell. A new cell has a different internal resistance profile, so the IC misreads the actual state of charge. When the modem fires or the screen peaks in brightness, voltage sags below what the IC expects — and the phone cuts off even though charge remains. One full discharge-to-shutdown followed by an uninterrupted charge to 100% forces the coulomb counter to reset against the new cell's actual curve. After that cycle, shutdowns at false low percentages stop.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003ePhone reports wrong battery percentage after BN37 installation\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe MIUI fuel gauge IC on the 6A uses a learned model built from the old cell's charge history. Swapping in a new BN37 cell means that stored model no longer matches real cell behaviour, so the percentage readout drifts — often jumping several points or stalling at a fixed number. A full calibration cycle corrects this: drain the battery until the phone shuts itself off, then charge straight to 100% without interruption. After one complete cycle the IC recalibrates and percentage tracking stabilises.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43392024641626,"sku":"BWCS-MUR610SL-1","price":24.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43392024674394,"sku":"BWCS-MUR610SL-2","price":27.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43392024707162,"sku":"BWCS-MUR610SL-3","price":30.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-MUR610SL-1.webp?v=1779142944","url":"https:\/\/batteryweb.com\/products\/redmi-6a-replacement-battery-385v-2900mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}