{"product_id":"tp-link-neffos-c7s-replacement-battery-38v-2500mah-li-ion","title":"TP-Link Neffos C7s Replacement Battery 3.8V 2500mAh NBL-43A2500","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eTP-Link Neffos C7s — 3.8V Li-ion Replacement Battery (NBL-43A2500)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.8V, 2500mAh (9.5Wh) Li-ion replacement battery for the TP-Link Neffos C7s smartphone, covering model variants TP7051A and TP7051C. It matches the OEM part number NBL-43A2500 and fits the original battery bay without modification. Use this to restore charge capacity when the original cell has degraded past the point of useful daily use.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eNeffos C7s variants (TP7051A, TP7051C):\u003c\/strong\u003e\n    Both variants run the same 3.8V rail, use the same connector pinout, and communicate with the same fuel gauge IC — this cell slots into either board without conflict.\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 a Neffos C7s board. The BMS accepted the cell without a protection trip, and the charge IC engaged correctly at both standard and fast-charge current levels.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst-cycle fast charge protocol:\u003c\/strong\u003e\n    On first use after installation, disable fast charging for one full discharge-charge cycle. The fuel gauge IC needs to map the new cell's discharge curve before high-current charging pushes into an uncalibrated state — skipping this causes percentage drift 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 Neffos C7s reports wrong battery percentage after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe fuel gauge IC on the C7s board stores a learned discharge curve from the original cell. When a new cell goes in, that stored curve no longer matches actual cell chemistry, so the IC reports inaccurate state-of-charge values — often reading 10–20% higher or lower than reality. The fix is one complete discharge down to automatic shutdown, followed by a full uninterrupted charge to 100%. After that cycle, the coulomb counter resets its reference points against the new cell and percentage reporting stabilises.\u003c\/p\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\"\u003eThis happens when the cell voltage drops below the BMS cutoff threshold under load — typically during simultaneous screen-on and mobile data activity — even though the OS reports remaining charge. A fresh Li-ion cell has a steeper voltage cliff than a broken-in one, so the BMS trips before the fuel gauge catches up. Run two full discharge-charge cycles without fast charging to let the cell's internal resistance stabilise. After break-in, the voltage under load at 20–30% should stay above the 3.2V BMS cutoff threshold and shutdowns stop.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43391985057882,"sku":"BWCS-TPC720SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43391985090650,"sku":"BWCS-TPC720SL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43391985123418,"sku":"BWCS-TPC720SL-3","price":29.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-TPC720SL-1.webp?v=1779142738","url":"https:\/\/batteryweb.com\/products\/tp-link-neffos-c7s-replacement-battery-38v-2500mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}