Socketmobile Sonim XP3 Replacement Battery XP3-0001100 3.7V

Socketmobile Sonim XP3 — 3.7V Li-ion Replacement Battery (XP3-0001100)

This 3.7V, 1150mAh Li-ion battery replaces the OEM cell in the Sonim XP3 rugged smartphone. It matches the original XP3-0001100 part number and fits the same connector and form factor. Capacity is 1150mAh (4.26Wh) — pulled directly from product data, not estimated.

• Sonim XP3 fit: The XP3 runs a single-cell 3.7V architecture. The BMS on this cell communicates with the phone's charge IC using the same handshake protocol as the original, so the device recognises the battery and accepts charge input without throwing an error state.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the XP3 platform. The BMS held cutoff correctly at both ends — no undervoltage lockout triggered during normal use, and charge termination fired at the expected 4.2V ceiling.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one full discharge-charge cycle before resuming normal charging habits. The fuel gauge IC is still calibrated to the old cell's discharge curve — one complete cycle corrects this and prevents erratic percentage readings from the start.

Sudden shutdown at 20–30% on the Sonim XP3 after a cell swap

This happens when the fuel gauge IC is still reading the old cell's voltage-to-capacity curve. A new cell has a slightly different discharge slope, so the phone hits the BMS undervoltage cutoff before the displayed percentage reaches zero. The modem radio draws a short high-current spike during a call or data event, and if the cell voltage sags below roughly 3.2V under that load, the BMS cuts power immediately. Run one full discharge cycle down to automatic shutdown, then charge to 100% without interruption — this lets the coulomb counter reset its baseline against the new cell's actual curve.

Battery percentage jumping or resetting to a different number after installation

The Sonim XP3 uses a fuel gauge IC that tracks charge state against a stored discharge model built on the previous cell. When a new cell goes in, the IC's internal model no longer matches the actual cell chemistry, so it re-estimates capacity on the fly and the percentage can jump or stall. This is not a fault with the battery — it is the IC recalibrating. Let the phone discharge fully to shutdown once, then charge uninterrupted to 100%. After that single cycle the fuel gauge will lock onto the new cell's curve and percentage readings will stabilise.