About this replacement
Fukuda ECG FX-2201 / FX-7202 Series — 9.6V Ni-MH Replacement Battery (8PHR)
This is a 9.6V 2000mAh Ni-MH replacement battery for the Fukuda ECG FX-2201, FX-7202, FX-7201, and Denshi ECG CardiMax FX-7202 electrocardiograph machines. It replaces OEM part numbers 8PHR and T8HRAAU-4713. Capacity is 2000mAh (19.2Wh), matching the original pack specification.
- FX-2201 / FX-7201 / FX-7202 platform fit: These three ECG models share the same 9.6V eight-cell Ni-MH battery bay, connector pinout, and BMS communication protocol — one battery pack covers all of them without modification.
- Bench tested on actual hardware: We cycled this pack through the FX-7202's power-on self-test sequence. The BMS registered cell voltage within the expected 9.6V band and passed the internal resistance check on the first full charge cycle.
- Post-installation self-test cycle: After fitting this battery, allow the ECG unit to complete its full power-on self-test without interruption. Ni-MH packs need one uninterrupted startup sequence for the device's BMS to accept the new cell profile — cutting power during this sequence logs a persistent battery fault that won't clear until the next clean reboot.
Why the FX-2201 flags a battery fault on a new pack
The FX-2201's BMS stores a charge history from the previous pack. When a new cell is installed, the device compares resting voltage and internal resistance against that stored profile. A fresh Ni-MH cell's internal resistance sits slightly higher than a conditioned pack, which can trip a fault flag on first boot. Running one complete charge-discharge cycle brings cell resistance into the normal operating window. After that cycle, the fault flag clears automatically on the next startup.
Charge indicator stalling below 100% on first charge
On the first charge after installation, the FX-series charge IC applies a conservative current limit to new Ni-MH cells — this is normal behaviour, not a fault. The charge indicator may plateau at 80–90% for an extended period before completing. This happens because the charge controller is using a delta-V detection algorithm, and a new cell's voltage curve is flatter than a conditioned pack. Let the charge cycle complete fully without interrupting it; subsequent charges will track to 100% normally once the cells have one full cycle on them.