CAT S62 Pro Replacement Battery 3.8V 4000mAh APP00317

CAT S62 Pro — 3.8V Li-Polymer Replacement Battery (APP00317)

This 3.8V, 4000mAh Li-Polymer cell replaces the original APP00317 battery in the CAT S62 Pro rugged smartphone. It restores power to the processor, display, modem, and FLIR thermal camera module. Dimensions are 72.20 × 59.50 × 5.70mm — matching the original cell footprint inside the S62 Pro chassis.

• S62 Pro compatibility: The S62 Pro uses a single-cell Li-Polymer pack with a proprietary connector and BMS handshake tied to the APP00317 part number. This cell matches the voltage rail, connector pinout, and BMS communication protocol the device expects.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the S62 Pro, confirming the BMS accepted the pack without fault codes, fast-charge negotiation initiated correctly after the first full cycle, and the protection circuit tripped cleanly at the low-voltage cutoff threshold.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging begins — skipping this step causes the OS to report inaccurate percentages for the first several cycles.

Sudden shutdown at 20–30% on the S62 Pro after a cell swap

The S62 Pro's fuel gauge IC retains the discharge curve from the old, degraded cell. When the new cell hits a voltage zone the IC incorrectly maps as 20–30%, the modem or display pulls a load spike the IC doesn't expect, and the device shuts down to protect against an undervoltage condition it thinks is imminent. This is a calibration mismatch, not a fault with the replacement cell. Run two full discharge-charge cycles with fast charging off — the coulomb counter will re-anchor itself to the new cell's actual voltage curve. After calibration, the shutdowns stop and reported percentage tracks correctly.

USB-PD fast charge not negotiating on the first cycle after replacement

On the first charge after a cell swap, the BMS in the new pack may present a high-impedance state that causes the charge IC to fall back from fast charge to standard 5V input. This is normal — the BMS is running initial cell characterisation. Plug in using the original CAT cable and charger, let the first cycle complete at standard rate without interrupting it, and check that the cable and port are clean and fully seated. By the second charge, the BMS handshake completes and USB-PD negotiation proceeds at full rate.