Socketmobile Sonim XP1 Replacement Battery 3.7V 1100mAh

Socketmobile Sonim XP1 Series — 3.7V Li-ion Replacement Battery (XP1-0001100)

This is a 3.7V Li-ion cell rated at 1100mAh (4.07Wh), built to the same spec as OEM part XP1-0001100. It fits the Sonim XP1, Sonim XP1 BT, and Sonim XP3 Enduro — three rugged smartphones built for industrial field use. Voltage and capacity match the original, so the phone's charge IC sees no mismatch on installation.

• XP1, XP1 BT, and XP3 Enduro compatibility: All three models share the same 3.7V battery bay, connector pinout, and BMS handshake requirements. One cell covers the full platform — no model-specific variants needed.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the XP1 platform. The BMS accepted the cell without fault flags, and the charge IC completed a full CC-CV cycle to rated capacity.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before high-current charging is applied to an uncalibrated cell.

Sudden shutdown at 20–30% on the Sonim XP1 after a cell swap

This happens because the fuel gauge IC is still using the discharge curve it learned from the old, degraded cell. The new cell has a steeper voltage cliff at low charge states, and the modem or screen load pulls the cell voltage below the BMS cutoff threshold before the OS reads 0%. The phone shuts off not because the cell is empty, but because the gauge is miscalibrated. Run one full discharge to auto-off, then charge uninterrupted to 100% — after that cycle, the gauge recalibrates and the shutdowns stop.

OS showing wrong battery percentage after replacement

Android's battery percentage reads from the fuel gauge IC, which tracks charge using a coulomb counter calibrated to the previous cell's internal resistance and capacity curve. A new cell with different impedance throws the counter off immediately. The gauge reports whatever value its stale model predicts, not what the cell actually holds. One full discharge-to-cutoff followed by a full uninterrupted charge resets the learned curve — after that cycle, percentage reporting stabilises.