{"product_id":"redmi-replacement-battery-38v-3900mah-li-polymer","title":"Redmi BM46 Replacement Battery 3.8V 3900mAh Li-Polymer","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eRedmi BM46 — 3.8V Li-Polymer Replacement Battery (BM46)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThe BM46 is a 3.8V, 3900mAh (14.82Wh) Li-Polymer cell that replaces the factory battery in Redmi smartphones carrying the BM46 part number. It fits the physical footprint at 74.61 × 60.20 × 5.60mm and connects via the original flex cable and BMS harness. If your phone shuts down early, charges slowly, or swells, this cell is the direct swap.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eBM46 platform fit:\u003c\/strong\u003e\n    Redmi devices on the BM46 platform share the same connector pinout, voltage rail, and BMS handshake. The replacement cell matches the original discharge curve so the fuel gauge IC can track capacity without misreporting state-of-charge.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through charge, load, and cutoff on BM46-compatible hardware. The BMS accepted the cell without a protection trip, and the coulomb counter initialised correctly on the first full discharge cycle.\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 pushes into an uncalibrated state-of-charge window.\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 replacement cell\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eA fresh BM46 cell has a steeper voltage cliff than a broken-in cell under modem or screen load. When the phone demands a current spike — LTE handoff, display brightness jump — the cell voltage dips below the BMS cutoff threshold before the reported percentage reaches zero. The fuel gauge IC hasn't yet mapped the new cell's internal resistance, so it reads capacity optimistically. Run one full discharge to 0% and a full charge to 100% without interruption; the coulomb counter resets its reference and the early shutdowns stop.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003ePhone feels warm near the battery on the first few charges\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eA new Li-Polymer cell comes with slightly higher internal impedance than a cell that has been cycled. The charge IC compensates by pushing a higher voltage differential across that impedance, which generates heat at the cell surface. This is normal for the first two to three cycles as the electrolyte settles and impedance drops. If the phone stays warm past the fifth charge, check that the battery flex connector is fully seated — a partial connection increases contact resistance and keeps impedance elevated.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43392112590938,"sku":"BWCS-MUM460XL-1","price":25.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43392112623706,"sku":"BWCS-MUM460XL-2","price":28.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43392112656474,"sku":"BWCS-MUM460XL-3","price":31.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-MUM460XL-1.webp?v=1779143848","url":"https:\/\/batteryweb.com\/products\/redmi-replacement-battery-38v-3900mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}