{"product_id":"blu-energy-x-replacement-battery-38v-3900mah-li-polymer","title":"BLU Energy X Compatible Battery 3.8V 3900mAh C816105400L","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eBLU Energy X \/ E010Q — 3.8V Li-Polymer Replacement Battery (C816105400L)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.8V, 3900mAh Li-Polymer cell that replaces the original battery in the BLU Energy X and E010Q smartphones. It fits the OEM battery slot directly and restores power to calls, messaging, and apps. Capacity matches the factory spec at 14.82Wh.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eEnergy X and E010Q compatibility:\u003c\/strong\u003e\n    Both variants share the same battery bay dimensions, connector pinout, and BMS handshake protocol — one cell covers both. The C816105400L part number is consistent across the full Energy X line.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this cell through full charge and discharge cycles on the Energy X platform. The BMS accepted charge current without rejection, and the protection circuit tripped correctly at low-voltage threshold without hard lockout.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration on first cycle:\u003c\/strong\u003e\n    After fitting this cell, disable fast charging and run one complete discharge-to-charge cycle at standard current. The fuel gauge IC needs to map the new cell's discharge curve before it can report accurate percentages — skipping this step causes erratic readings for the first several cycles.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the Energy X reports wrong battery percentage after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe BLU Energy X uses a coulomb-counting fuel gauge IC that builds its capacity model against the original cell's discharge curve over dozens of cycles. When you install a fresh cell, that learned curve no longer applies. The IC keeps using the old model, so percentage readings can jump or stall — typically appearing full for too long, then dropping fast toward 20%. One full slow-charge cycle forces the IC to re-anchor its zero and full reference points against the new cell chemistry.\u003c\/p\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\"\u003eThis happens when the modem or display draws a current spike the cell cannot sustain at its present state of charge. Voltage sags below the shutdown threshold — typically around 3.2V under load — before the reported percentage reaches zero. The phone cuts power to protect the circuit even though the gauge shows charge remaining. Run two full discharge-charge cycles and check that shutdown moves closer to 5% or below; if it persists above 15%, confirm the cell seated fully and the connector pins are making clean contact.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43392071991386,"sku":"BWCS-BLE010SL-1","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43392072024154,"sku":"BWCS-BLE010SL-2","price":30.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43392072056922,"sku":"BWCS-BLE010SL-3","price":33.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-BLE010SL-1.webp?v=1779143621","url":"https:\/\/batteryweb.com\/products\/blu-energy-x-replacement-battery-38v-3900mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}