Sonim XP3800 Replacement Battery 3.7V 1400mAh Li-ion

Sonim XP3800 / XP3 — 3.7V Li-ion Replacement Battery (BAT-01500-01)

This is a 3.7V, 1400mAh Li-ion battery that fits the Sonim XP3800 and XP3 rugged smartphones. It replaces OEM part BAT-01500-01 and BAT-01500-01S. Swap it in when the original cell can no longer hold a charge through a full shift.

• XP3800 and XP3 compatibility: Both models run the same voltage rail and share an identical battery bay footprint — 53.40 × 37.80 × 6.30mm — so one cell covers the full range. The connector pinout and BMS handshake are the same across both variants.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the XP3800 platform. The BMS communicated cleanly with the charge IC, accepted a full charge without interruption, and held the voltage rail stable under simultaneous screen and modem load.
• Fuel gauge recalibration on first use: On first installation, disable fast charging and run one complete discharge-to-charge cycle at standard current. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell.

Sudden shutdown at 20–30% on the XP3800 after a cell swap

The XP3800's fuel gauge IC retains the discharge curve from the old cell. When a new cell is installed, the coulomb counter is still referencing that old curve. The phone reads 25% remaining, but the actual cell voltage has already dropped below the threshold the modem and display need under load. The hardware protection circuit cuts power before the OS can catch it. One full discharge cycle — draining to automatic shutdown and charging back to 100% — forces the fuel gauge IC to rebuild its internal map against the new cell.

XP3800 not powering on after storage with a depleted battery

If a Li-ion cell sits discharged for weeks, the cell voltage can drop below 2.5V per cell — the threshold where the BMS locks out charging to protect against plating. The XP3800 will show no response on the power button and no charge indicator on the screen. Connect the phone to a low-current USB source and leave it for 15–30 minutes without pressing anything — the charge IC on some units will trickle current into a locked-out cell to recover it above the 2.5V floor. If the device still shows nothing after that window, check that the charger is outputting at least 5V at the port before assuming the battery is unrecoverable.