{"product_id":"att-4058r-replacement-battery-38v-1750mah-li-ion","title":"AT\u0026T TLi017C7 4058R Replacement Battery 3.8V 1750mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eAT\u0026amp;T 4058R — 3.8V Li-ion Replacement Battery (TLi017C7)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.8V, 1750mAh Li-ion replacement battery for the AT\u0026amp;T 4058R smartphone. It replaces OEM part number TLi017C7 and fits the 4058R directly. Use this when the original cell no longer holds voltage under screen or modem load.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eAT\u0026amp;T 4058R compatibility:\u003c\/strong\u003e\n    The 4058R uses the TLi017C7 form factor — a 60.10 × 46.30 × 5.30mm cell with a 3.8V nominal rail and a matching connector pinout. The BMS handshake on this device authenticates by voltage threshold and connector wiring, not a proprietary chip, so the replacement cell negotiates correctly on first boot.\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 the 4058R platform and confirmed the BMS accepted the cell without error flags. Charge termination triggered at the correct cutoff voltage and the fuel gauge IC registered the cell without prompting a calibration warning on boot.\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. The fuel gauge IC on the 4058R calibrates its coulomb counter against the cell's actual discharge curve. Running a slow cycle first lets the IC map the new cell accurately before high-current charging begins.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the AT\u0026amp;T 4058R reports wrong battery percentage after a cell swap\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe 4058R uses a fuel gauge IC that stores a learned discharge curve from the original cell. When a new cell goes in, that stored curve no longer matches the actual cell chemistry, so the percentage readout drifts. The IC needs at least one full discharge-charge cycle to rewrite its internal model. Drain the phone to automatic shutdown, then charge uninterrupted to 100% — after that cycle the percentage display stabilises.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eSudden shutdown at 20–30% on the AT\u0026amp;T 4058R after replacement\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThis happens when the fuel gauge IC is still running the old cell's voltage curve. The new cell hits a voltage cliff under modem or display load at a point the IC still interprets as 20–30% remaining. The phone's low-voltage protection fires and cuts power before the gauge reaches zero. Run one full slow-charge cycle without fast charging enabled — once the coulomb counter recalibrates to the new cell, the shutdown point drops back to the correct near-zero threshold.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43392067076186,"sku":"BWCS-OTS406XL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43392067108954,"sku":"BWCS-OTS406XL-2","price":26.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43392067141722,"sku":"BWCS-OTS406XL-3","price":28.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-OTS406XL-1.webp?v=1779143561","url":"https:\/\/batteryweb.com\/products\/att-4058r-replacement-battery-38v-1750mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}