Launch X-431 Turbo L19D1P31 Replacement Battery 3.85V 4900mAh

Launch X-431 Turbo Diagnostic — 3.85V Li-Polymer Replacement Battery (L19D1P31)

This is a 3.85V, 4900mAh Li-Polymer replacement cell for the Launch X-431 Turbo diagnostic tablet. It fits the X-431 Turbo — a professional automotive scan tool used for live vehicle diagnostics, ECU coding, and software updates. Capacity is rated at 18.87Wh, matching the original L19D1P31 specification.

• X-431 Turbo platform fit: The X-431 Turbo uses the L19D1P31 cell with a flat Li-Polymer form factor at 115.54 × 97.50 × 2.50mm. The BMS connector pinout and voltage rail match the original, so the charge IC on the tablet communicates with the replacement cell without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the X-431 Turbo platform. The BMS accepted the new cell on first connection, charge current stepped correctly through CC and CV phases, and no protection cutoff events were triggered during load testing.
• Fuel gauge recalibration after swap: After installation, run the tablet down to automatic shutoff, then charge uninterrupted to 100% without using the device. This forces the fuel gauge IC to recalibrate against the new cell and eliminates the inaccurate percentage readings that appear immediately after a battery swap.

X-431 Turbo shutting down at 15–25% remaining after battery replacement

This happens because the fuel gauge IC still holds calibration data from the degraded original cell. The old cell had a steep voltage cliff at low charge — the IC learned that cutoff occurs early. With a fresh cell, the voltage curve is different, but the IC still triggers shutdown at the same learned threshold. Running one full discharge-to-shutoff cycle followed by an uninterrupted charge resets the calibration. After that cycle, the tablet should reach genuine 0% before shutting down rather than cutting at 20%.

Fast charging not available on the X-431 Turbo after a battery swap

The X-431 Turbo's charge IC negotiates charge rate partly based on battery state data from the new cell. On first connection, the IC defaults to standard charge current until it has completed one accepted charge cycle and confirmed cell behaviour. Plug in using the original charger and let the tablet complete a full charge without interruption. Fast charge typically becomes available from the second charge cycle onward once the IC has logged a clean initial cycle against the replacement cell.