Crosscall Trekker X3 Replacement Battery LPN385350 3.85V 3400mAh

Crosscall Trekker X3 / Core-X3 / Action-X3 — 3.85V Li-Polymer Replacement Battery (LPN385350)

This 3.85V, 3400mAh Li-Polymer cell replaces part number LPN385350 in the Crosscall Trekker X3, Core-X3, and Action-X3 rugged smartphones. It matches the original cell's dimensions (64.60 × 56.20 × 5.80mm) and voltage rail exactly. Capacity is 3400mAh — use this figure, not third-party listings that vary.

• Trekker X3 / Core-X3 / Action-X3 platform compatibility: These models share the same battery bay geometry, connector pinout, and BMS handshake protocol. One cell revision covers all three without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a Trekker X3 unit. The BMS accepted the cell on first insertion, thermal cutoff triggered correctly at the upper charge limit, and the protection circuit responded to over-discharge as expected.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-charge cycle at standard rate. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging introduces error into the coulomb counter.

Sudden shutdown at 20–30% on a replacement cell in the Trekker X3

This is a voltage cliff issue, not a capacity problem. Under peak modem or screen load, a new cell with an uncalibrated fuel gauge can drop below the BMS cutoff voltage momentarily — the phone shuts down even though the reported percentage looks healthy. The fuel gauge IC inherited calibration data from the old, degraded cell and is misreading the new cell's discharge curve. Run two full discharge-charge cycles at standard charge rate and the coulomb counter will remap to the new cell, pushing the apparent shutdown point back toward 0%.

USB-PD fast charge not activating after a cell swap

After fitting a new cell, some Trekker X3 units refuse to negotiate fast charge on the first cycle. The charge IC defaults to a conservative current limit when it detects a new cell with higher internal impedance than the depleted original. This is a safety state, not a fault. Charge once at standard rate to let the IC profile the new cell, then reconnect with your fast charger — fast charge will engage normally from the second cycle onward.