AT&T F160 Replacement Battery 3.7V 800mAh Li-ion

AT&T F160 — 3.7V Li-ion Replacement Battery

This is a 3.7V, 800mAh lithium-ion battery for the AT&T F160 mobile phone. It replaces the original cell when the phone can no longer hold a charge or fails to power on. Dimensions are 54.29 x 33.71 x 4.43mm — measure your original before installing.

• F160 platform fit: The F160 uses a compact single-cell Li-ion pack at 3.7V nominal. The charge IC on this phone communicates directly with the cell through a shared ground — incorrect cell impedance will cause the charger to reject the battery or deliver erratic current, so voltage and physical tolerances both matter.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a calibrated test rig. The BMS held cutoff correctly at both ends — no premature low-voltage lockout and no overcharge past 4.2V. Charge acceptance was stable across the full cycle.
• Fuel gauge recalibration on first use: On first installation, disable any fast-charge mode and run one complete discharge-to-charge cycle at standard current. This gives the fuel gauge IC a full reference curve against the new cell — without it, the phone's percentage readout will track the old cell's profile, not this one.

Sudden shutdown at 20–30% on the F160 after a cell swap

The F160's fuel gauge IC stores a discharge curve calibrated to the original cell's internal resistance profile. A new cell has different impedance, so the gauge misjudges remaining capacity. Under load — backlight, modem polling, or a call — voltage drops faster than the gauge predicts, and the phone shuts off before it reports zero. One full discharge cycle from 100% to automatic shutdown, followed by a full charge, resets the coulomb counter reference. After that cycle, shutdowns in the 20–30% range should stop.

Phone not powering on after the battery sat in storage

Li-ion cells discharge slowly in storage. If the voltage drops below roughly 2.5V, the BMS trips a deep-discharge lockout to protect the cell from permanent damage. The phone will show nothing — no charging animation, no response to the power button. Connect the phone to a wall charger, not a USB port, and leave it for 20–30 minutes without pressing anything. The charge IC needs to push a small recovery current into the cell before the BMS re-enables the output rail. Once the voltage recovers above 3.0V, the phone will boot normally.