{"product_id":"apple-iphone-4g-replacement-battery-37v-1300mah-li-ion","title":"Apple iPhone 4G Replacement Battery 3.7V 1300mAh 616-0520","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eApple iPhone 4G — 3.7V Li-ion Replacement Battery (616-0520)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V 1300mAh Li-ion replacement cell for the Apple iPhone 4G, iPhone 4G 16GB, and iPhone 4G 32GB. It matches the original cell dimensions at 115.70 x 63.20 x 15.80mm and connects to the same three-pin flex connector on the logic board. Voltage and capacity figures come from the product data, not estimated values.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eiPhone 4G 16GB and 32GB compatibility:\u003c\/strong\u003e\n    Both storage variants use the same battery bay, connector pinout, and charge IC configuration. The only difference between them is NAND storage — the battery circuit is identical across the lineup, so one cell fits all three models.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell on an iPhone 4G logic board and confirmed the BMS handshake with the charge IC. The cell accepted charge current without error flags and held voltage through a full discharge sweep without tripping the protection circuit prematurely.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration after swap:\u003c\/strong\u003e\n    On first use after installation, run one complete discharge down to automatic shutdown, then charge uninterrupted to 100% before using the phone. This gives the coulomb counter IC a full reference cycle against the new cell's actual discharge curve before iOS begins drawing current under mixed loads.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the iPhone 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 iPhone 4G uses a stored discharge curve from the previous cell to estimate remaining charge. When a new cell goes in, that stored curve no longer matches the actual cell chemistry and impedance. The result is a percentage reading that drifts — often reading 20% when the cell still has significant charge remaining, or jumping unexpectedly. One full discharge-to-shutdown followed by a full uninterrupted charge resets the coulomb counter reference and brings the percentage display back into line.\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 pulls a current spike that drops cell voltage below the BMS cutoff threshold — typically around 3.0V — even though the fuel gauge still shows charge remaining. A new cell with an uncalibrated fuel gauge IC makes this worse because iOS cannot anticipate the voltage cliff. The fix is the same calibration cycle: discharge fully to auto-shutdown, then charge to 100% without interruption. After one full cycle, iOS maps the cell's real voltage curve and the premature shutdowns stop.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405116473434,"sku":"BWCS-IPH440EX-1","price":37.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 2 Year","offer_id":43405116506202,"sku":"BWCS-IPH440EX-2","price":43.99,"currency_code":"USD","in_stock":false},{"title":"Warranty 3 Year","offer_id":43405116538970,"sku":"BWCS-IPH440EX-3","price":47.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-IPH440EX-big.webp?v=1779369992","url":"https:\/\/batteryweb.com\/products\/apple-iphone-4g-replacement-battery-37v-1300mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}