About this replacement
XTOOL X100 Pad2 / EZ500HD Series — 7.4V Li-Polymer Replacement Battery (MK5725)
This 7.4V 4000mAh Li-Polymer battery replaces the OEM MK5725 cell in the XTOOL X100 Pad2 and EZ500HD diagnostic scanners. It fits the full EZ500HD Heavy Duty and Gasoline EZ500 variants as well. Same voltage rail, same physical footprint at 125.60 × 66.60 × 8.00mm, same connector and BMS handshake as the original.
- X100 Pad2 and EZ500HD platform fit: These models share the same 7.4V two-cell Li-Polymer architecture, identical connector pinout, and matching BMS communication protocol — which is why one cell covers the entire range without modification.
- Bench tested on actual hardware: We ran this cell through full charge-discharge cycles on the X100 Pad2 and verified BMS handshake at power-on. The scanner recognised the battery immediately, reported accurate state-of-charge, and the protection circuit tripped correctly at low-voltage cutoff.
- Data export before swap: The X100 Pad2 stores active vehicle profiles and session logs in RAM backed by the main battery. Pull power without exporting first and that data is gone. Use the scanner's built-in export function to save all vehicle profiles to SD card or USB before removing the old cell.
Why the X100 Pad2 won't boot after a battery swap
A freshly shipped Li-Polymer cell typically arrives at 30–50% state of charge. The X100 Pad2 has a boot-voltage threshold — if the cell sits below roughly 3.5V per cell (7.0V pack), the scanner refuses to start rather than risk an incomplete flash cycle corrupting firmware. This is not a faulty battery. Connect the scanner to the OEM charger and leave it for at least 30 minutes before attempting to power on. Once the pack clears the boot threshold the scanner starts normally.
Wireless connection dropping mid-diagnostic session
The X100 Pad2's Bluetooth and Wi-Fi modules draw a sharp current spike when maintaining an active vehicle link. At low battery states the voltage sags enough that the wireless radio resets, killing the session mid-scan. This happens well before the battery indicator shows empty because the display controller reads average voltage while the radio responds to instantaneous sag. If connections drop repeatedly, check pack voltage under load — anything below 7.2V under active wireless use means the cell needs replacing. A fresh 4000mAh cell eliminates the sag margin issue entirely.