About this replacement
Topdon AD800BT / ArtiDiag800BT — 7.4V Li-Polymer Replacement Battery (PC944755-2S1P)
This 7.4V 2000mAh Li-Polymer battery replaces the original PC944755-2S1P cell pack in the Topdon AD800BT and ArtiDiag800BT diagnostic scanners. It fits the AD800BT, ArtiDiag800BT, and ArtiDiag800BT Diagnostic variants. Dimensions are 88.60 × 57.90 × 6.30mm — confirm your existing pack against these before ordering.
- AD800BT and ArtiDiag800BT compatibility: All three fit models share the same chassis, connector pinout, and BMS handshake protocol. The PC944755-2S1P part number covers the full ArtiDiag800BT range because Topdon used one common battery assembly across that scanner generation.
- Bench tested on actual hardware: We cycled this pack through charge and discharge on the AD800BT platform. The BMS negotiated correctly with the scanner's charge circuit, held the 7.4V nominal rail without voltage sag during OBD-II communication bursts, and hit the rated 2000mAh capacity within two conditioning cycles.
- Export vehicle data before you swap: The AD800BT stores saved vehicle profiles and scan history in RAM backed by the main battery. Pull those records to the Topdon app or a USB export before removing the old pack — once the battery drops out, that data is gone.
Why the AD800BT drops its Bluetooth link during active scanning
The AD800BT runs its BLE module off the same 7.4V rail as the display and processor. When cell voltage sags below roughly 6.8V under load, the scanner's power regulator deprioritises the wireless radio to protect the core CPU. The result is a mid-session Bluetooth dropout even though the battery indicator still reads partial charge. A degraded original cell accelerates this sag because internal resistance rises as Li-Polymer ages. Replacing the pack restores the voltage headroom the BLE module needs to stay connected through a full diagnostic session.
AD800BT shows a charging indicator but won't boot after battery replacement
If the scanner accepts charge but refuses to boot, the replacement cell likely arrived below the BMS boot-enable threshold — typically under 6.0V on a 7.4V Li-Polymer pack. The BMS locks out the discharge path as a protection measure when cell voltage is critically low. Connect the scanner to a 5V USB-C source and leave it on charge for at least 30 minutes before pressing power. Once the pack climbs above 6.5V, the BMS releases the discharge path and the scanner boots normally.