AT&T GoPhone 4G LTE Replacement Battery 3.8V 1450mAh

AT&T GoPhone 4G LTE — 3.8V Li-ion Replacement Battery

This 3.8V, 1450mAh (5.51Wh) lithium-ion cell replaces the original battery in the AT&T GoPhone 4G LTE prepaid smartphone. It restores power to the handset when the factory cell no longer holds a charge or has failed outright. Dimensions are 69.42 × 47.94 × 4.75mm — confirm your original before fitting.

• GoPhone 4G LTE fit: This cell matches the voltage rail and physical footprint the GoPhone 4G LTE requires. The 3.8V nominal output keeps the modem, screen, and baseband processor within their rated input range without triggering low-voltage shutdown on startup.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a GoPhone-class load profile. The BMS held charge cutoff at 4.2V and triggered protection at the correct low-voltage threshold — no false trips on modem transmit bursts.
• Fuel gauge recalibration on first use: On first use after fitting, disable fast charging and run one complete discharge-to-charge cycle. The GoPhone's fuel gauge IC is calibrated to the old cell's discharge curve — one full cycle lets it map the new cell before resuming high-current charging.

Sudden shutdown at 20–30% on the GoPhone 4G LTE

This happens when the cell cannot sustain voltage under a combined screen-plus-modem load spike. At around 3.5V, the GoPhone's power management IC reads a valid percentage on paper, but a brief current draw collapses the cell voltage below the cutoff threshold. The device shuts down before the percentage gauge reaches zero. One full discharge-charge cycle lets the fuel gauge IC replot the actual discharge curve so the shutdown point aligns with true cell depletion.

Phone not powering on after the replacement cell sat in storage

If the replacement cell was stored for an extended period, its resting voltage may have dropped below 2.5V — the threshold at which the BMS locks out to prevent cell damage. The GoPhone will show no sign of life and will not respond to a standard charger. Connect to a USB power source and leave it undisturbed for 15–30 minutes; the BMS trickle-charge circuit will attempt to bring the cell back above the lockout threshold before allowing normal charge current. If the cell does not recover to 3.0V within that window, the cell is below recoverable range.