{"product_id":"poco-x3-nfc-replacement-battery-385v-4950mah-li-polymer","title":"Poco X3 NFC Replacement Battery BN57 3.85V 4950mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003ePoco X3 NFC — 3.85V Li-Polymer Replacement Battery (BN57)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.85V, 4950mAh lithium-polymer replacement battery for the Poco X3 NFC (model M2007J20CG). It fits the original BN57 slot directly, matching the physical dimensions of 89.00 × 64.00 × 4.72mm. Capacity is rated at 19.06Wh, in line with the original cell specification.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eX3 NFC and M2007J20CG compatibility:\u003c\/strong\u003e\n    Both model identifiers reference the same hardware platform. They share the same battery bay geometry, connector pinout, and BMS handshake protocol — one cell fits both.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through a full charge cycle on an X3 NFC unit. The BMS accepted the charge handshake without fault flags, and the fuel gauge IC initialised correctly after one complete discharge-charge pass.\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 and run one full discharge-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's discharge curve before Turbo Charge pushes high current into 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 Poco X3 NFC after a cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens because the fuel gauge IC is still reading from the old cell's discharge curve. The new cell hits a voltage cliff — it cannot sustain rail voltage under simultaneous modem, display, and CPU load — even though the percentage shown looks safe. The phone's power management IC cuts the rail before the OS can log a proper shutdown. One full discharge-charge cycle with fast charging off forces the coulomb counter to rebuild its curve against the new cell and eliminates the false floor.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eUSB Turbo Charge not triggering after fitting a replacement BN57\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eTurbo Charge negotiation runs between the charger IC and the BMS on first contact. A new cell with a fresh BMS sometimes completes the initial handshake in standard 5V mode rather than elevated-voltage fast-charge mode. This typically resolves after the first full standard charge cycle, once the BMS has logged a complete charge event. If fast charging still does not trigger after two cycles, check that the cable supports the required current rating — a USB 2.0 data cable will cap current regardless of charger output.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43391906709594,"sku":"BWCS-MUM207SL-1","price":31.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43391906742362,"sku":"BWCS-MUM207SL-2","price":36.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43391906775130,"sku":"BWCS-MUM207SL-3","price":39.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-MUM207SL-1.webp?v=1779142596","url":"https:\/\/batteryweb.com\/products\/poco-x3-nfc-replacement-battery-385v-4950mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}