{"product_id":"poco-m4-pro-replacement-battery-387v-4900mah-li-polymer","title":"Poco M4 Pro BN5D Replacement Battery 3.87V 4900mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003ePoco M4 Pro — 3.87V Li-Polymer Replacement Battery (BN5D)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.87V, 4900mAh Li-Polymer cell for the Poco M4 Pro (model 2201117PG). It replaces a degraded or failed BN5D battery and restores full electrical capacity to the device. Fit is confirmed against the original 87.20 × 63.30 × 5.20mm footprint and connector position.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eM4 Pro compatibility:\u003c\/strong\u003e\n    The M4 Pro uses a single-cell Li-Polymer pack with a 4-pin BMS connector that carries cell voltage, thermistor, and ID data to the charge IC. This BN5D replacement matches that connector pinout and BMS handshake — no adapter needed.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through charge and discharge cycles on the M4 Pro platform. The BMS accepted charge IC communication on first connection, and the thermistor line reported correctly throughout the test sequence.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    After installation, disable fast charging and run one full discharge-to-charge cycle at standard current. This lets the fuel gauge IC map its coulomb counter against the new cell's actual 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 replacement cell\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eA new cell has a different internal resistance profile than the worn cell the fuel gauge IC learned from. Under peak modem, display, or processor load, voltage sags faster than the gauge predicts — and the protection circuit trips before the reported percentage reaches zero. The phone reads 25% but the cell is already below the BMS cutoff threshold under that load. One full discharge-to-charge cycle recalibrates the coulomb counter and eliminates most of these false cutoffs.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eUSB-PD fast charge not recognised on first cycle after swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eOn first boot with a new BN5D, the charge IC may default to trickle charge until it completes a handshake with the BMS and confirms the cell is within safe temperature and voltage range. If fast charge appears unavailable in settings or the brick reverts to 5W output, let the phone charge fully at standard rate first. After one complete cycle, the charge IC re-enables the fast charge negotiation path. Confirm the fast charge icon returns at voltages above 3.6V on the second charge.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43391844909146,"sku":"BWCS-MUN511SL-1","price":34.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43391844941914,"sku":"BWCS-MUN511SL-2","price":40.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43391844974682,"sku":"BWCS-MUN511SL-3","price":44.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-MUN511SL-1.webp?v=1779142367","url":"https:\/\/batteryweb.com\/products\/poco-m4-pro-replacement-battery-387v-4900mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}