{"product_id":"mobistel-cynus-f7-4g-replacement-battery-38v-2200mah-li-polymer","title":"Mobistel Cynus F7 4G Compatible Battery 3.8V 2200mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eMobistel Cynus F7 4G — 3.8V Li-Polymer Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.8V, 2200mAh Li-Polymer battery for the Mobistel Cynus F7 4G smartphone. It replaces the original cell when the factory battery no longer holds a useful charge or has failed entirely. Dimensions are 76.50 x 59.80 x 3.00mm — confirm clearance inside the chassis before fitting.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eCynus F7 4G compatibility:\u003c\/strong\u003e\n    The Cynus F7 4G runs a single-cell Li-Polymer pack at 3.8V nominal. This replacement matches that voltage rail and the physical footprint of the OEM cell, so the connector seats 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 under modem-active and screen-on load conditions. The BMS held cutoff correctly at both ends of the charge window with no unexpected trips.\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 current into an uncalibrated state.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the Cynus F7 4G reports wrong battery percentage after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe fuel gauge IC on the Cynus F7 4G stores a learned discharge curve from the old cell. When a new cell goes in, that stored model no longer matches the actual cell chemistry. The phone reads voltage and maps it to the old curve, so the percentage shown can be off by 10–20 points. One full discharge down to automatic shutdown followed by an uninterrupted charge to 100% resets the coulomb counter and aligns the gauge to the new cell.\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 cell voltage drops sharply under load — typically during an LTE data burst or a bright screen event — faster than the fuel gauge expects. The phone sees the voltage cliff as a fault and cuts power before the percentage reaches zero. It is not a defective cell in most cases; it is the gauge IC still working from the old calibration. Run one full discharge-charge cycle without interruption, then check whether the shutdowns stop. If the cell voltage at shutdown is above 3.4V on a meter, the gauge recalibration has not completed — repeat the cycle.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43392089653338,"sku":"BWCS-ZTV600SL-1","price":24.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43392089686106,"sku":"BWCS-ZTV600SL-2","price":27.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43392089718874,"sku":"BWCS-ZTV600SL-3","price":30.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-ZTV600SL-1.webp?v=1779143708","url":"https:\/\/batteryweb.com\/products\/mobistel-cynus-f7-4g-replacement-battery-38v-2200mah-li-polymer","provider":"BatteryWeb","version":"1.0","type":"link"}