Sonim XP3 Replacement Battery 3.7V 1150mAh Li-ion

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

This is a 3.7V 1150mAh Li-ion battery for the Sonim XP3 rugged smartphone. It replaces part number XP3-0001100 when the original cell degrades or fails to hold a charge. Capacity figures come from the product data, not estimates.

• XP3 fit: The XP3 runs a single-cell 3.7V architecture with a proprietary connector and BMS handshake tied to the phone's fuel gauge IC. This cell matches that voltage rail and physical footprint — 56.15 x 35.54 x 6.40mm — so the BMS negotiation completes on first boot.
• Bench tested on actual hardware: We cycled this cell under a load profile simulating the XP3's modem and display draw. The BMS held cutoff correctly at both ends of the charge curve, and charge termination triggered cleanly at full capacity without thermal flags.
• Fuel gauge recalibration on first install: After fitting this cell, disable fast charging and run one full discharge-to-charge cycle before resuming normal use. The XP3's fuel gauge IC is calibrated to the old cell's discharge curve. One full cycle rewrites that reference, so the coulomb counter tracks accurately going forward.

Why the XP3 reports wrong battery percentage after a cell swap

The XP3 uses a fuel gauge IC that builds its capacity model from accumulated charge and discharge data on the original cell. When you swap the cell, the IC still references the old discharge curve. It will show inflated or deflated percentages until it maps the new cell's actual voltage-to-capacity relationship. One complete discharge — down to automatic shutdown — followed by a full charge to 100% resets the learned curve. After that cycle, readings stabilise.

Sudden shutdown at 20–30% on the Sonim XP3

This is a voltage cliff failure, not a capacity problem. Under modem transmission or screen-on load, the cell voltage drops faster than the fuel gauge predicts — the phone's low-voltage protection trips before the displayed percentage hits zero. It happens most often when the fuel gauge IC hasn't yet recalibrated to the new cell. Run one full calibration cycle first. If shutdowns continue after that, check the resting voltage at shutdown — it should read above 3.4V; anything below that points to a contact or seating issue in the battery compartment.