{"product_id":"microsoft-lumia-640-lte-replacement-battery-38v-2400mah-li-ion","title":"BV-L5C Compatible Battery for Microsoft Lumia 640 LTE 3.8V 2400mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eMicrosoft Lumia 640 LTE — 3.8V Li-ion Replacement Battery (BV-L5C)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.8V, 2400mAh Li-ion replacement cell for the Microsoft Lumia 640 LTE and Lumia 640 Dual SIM smartphones. It replaces OEM part number BV-L5C directly. Capacity is rated at 9.12Wh and dimensions are 93.50 × 37.30 × 5.20mm — confirming fitment before you open the phone is worth the 30 seconds.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eLumia 640 LTE and 640 Dual SIM compatibility:\u003c\/strong\u003e\n    Both models share the same battery bay geometry, connector pinout, and BMS communication protocol — the BV-L5C cell fits both 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 Lumia 640 LTE unit. The BMS handshake completed on first connection, charge IC accepted the cell without flagging an error, and voltage held steady through a full discharge curve.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first use:\u003c\/strong\u003e\n    After installing this cell, disable fast charging and run one full discharge-to-charge cycle before returning to normal use. The fuel gauge IC on the Lumia 640 is calibrated to the old cell's discharge curve — one complete cycle lets it map the new curve accurately and prevents erratic percentage readings early on.\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 Lumia 640 after a cell swap\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the fuel gauge IC is still running the old cell's voltage-to-capacity curve. The replacement cell hits a voltage cliff — a sharp drop in cell voltage under modem or screen load — at a point the OS still reads as 20–30% remaining. The phone interprets that voltage drop as a critical low and cuts power. One full discharge cycle from 100% down to automatic shutdown, followed by a full charge, resets the coulomb counter and aligns the gauge to the new cell's actual curve.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003ePhone won't power on after the replacement battery sat in storage\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eLi-ion cells self-discharge during storage. If this cell dropped below 2.5V, the BMS will have entered lockout mode and will refuse to accept a charge current to protect the cell from damage. Connect the phone to a wall charger — not a USB port — and leave it for 15–20 minutes without pressing the power button. A wall charger delivers enough trickle current to nudge the cell voltage back above the BMS recovery threshold, typically around 2.8–3.0V, at which point the BMS re-initialises and normal charging resumes.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43392061735002,"sku":"BWCS-NK642SL-1","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43392061767770,"sku":"BWCS-NK642SL-2","price":29.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43392061800538,"sku":"BWCS-NK642SL-3","price":32.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-NK642SL-1.webp?v=1779143526","url":"https:\/\/batteryweb.com\/products\/microsoft-lumia-640-lte-replacement-battery-38v-2400mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}