AT&T GoPhone 4G LTE Replacement Battery 3.8V 1950mAh

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

This 3.8V, 1950mAh (7.41Wh) lithium-ion cell replaces the original battery in the AT&T GoPhone 4G LTE prepaid smartphone. It fits the standard battery bay and connects through the existing contacts without modification. Use this when the original cell no longer holds adequate charge and the device needs to stay in service.

• GoPhone 4G LTE fit: The AT&T GoPhone 4G LTE uses a removable 3.8V single-cell pack with a fixed contact strip along the bottom edge. This cell matches that voltage rail and physical footprint — 69.42 × 47.94 × 4.75mm — so it seats correctly in the battery bay without stressing the cover or contacts.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the GoPhone 4G LTE platform. The BMS accepted the charge current without fault flags, and the protection circuit responded correctly to both low-voltage cutoff and over-current events during modem activity.
• Fuel gauge recalibration on first use: After installing this cell, disable fast charging if your charger supports it and run one complete discharge-charge cycle at standard current. This allows the fuel gauge IC to map the new cell's discharge curve before the OS reports accurate percentages.

Sudden shutdown at 20–30% on the GoPhone 4G LTE after a cell swap

A new cell has a discharge curve the phone's fuel gauge IC has never seen before. When the modem transmits or the screen peaks in brightness, current draw spikes sharply. If the fuel gauge still maps those loads against the old cell's curve, it underestimates the voltage drop — and the phone shuts down before the reported percentage reaches zero. This is not a defective cell. Running one full discharge cycle down to automatic shutdown, then charging uninterrupted to 100%, gives the coulomb counter enough data to recalibrate. After that cycle, the shutdowns stop.

Phone not powering on after the replacement cell sat in storage

Lithium-ion cells self-discharge in storage. If this cell arrived or was stored at a voltage below roughly 2.5V per cell, the BMS may have tripped into deep-discharge lockout to prevent damage. The phone will not respond to a normal power press. Connect the device to a wall charger — not a USB port — and leave it for at least 20 minutes before attempting to power on. The charge IC will trickle current into the cell until the BMS exits lockout, typically above 3.0V, at which point normal charging resumes.