About this replacement
Fukuda Cardimax FX-8222 / FX-8322 — 11.1V Li-ion Replacement Battery (BTE-001)
This 11.1V, 3800mAh Li-ion battery replaces OEM part BTE-001 in the Fukuda Cardimax FX-8222, FX-8222, FX-8322, and FX-8322R portable electrocardiographs. It fits the same battery bay and connector as the original. Capacity is rated at 42.18Wh.
- FX-8222 and FX-8322 platform compatibility: Both device families run the same 11.1V three-cell architecture and share the BTE-001 connector pinout and BMS communication protocol. A single replacement covers all listed variants without modification.
- Bench tested on actual hardware: We cycled this cell through the FX-8222 charge circuit and confirmed the BMS handshake completed correctly. State-of-charge reporting was accurate from the second cycle onward after the initial calibration pass.
- Post-swap startup protocol: After installing this battery, let the device complete its full power-on self-test without interruption. The FX-8222's BMS runs a verification sequence at boot — cutting power mid-cycle locks in a false battery fault that clears only on a clean full reboot.
Why the FX-8222 reports a battery fault on a brand-new cell
The Cardimax FX-8222 uses a charge IC that applies conservative acceptance thresholds on cells it hasn't profiled before. A new BTE-001 cell may not pass the internal impedance check on the first cycle because the electrolyte hasn't fully wetted all electrode surfaces. This isn't a defective battery — it's the BMS treating an unproven cell cautiously. One full charge-to-discharge cycle is enough for the device to build a baseline and clear the fault permanently.
Device won't power on after the battery sat in storage
Li-ion cells self-discharge during storage — if voltage drops below approximately 9V, the FX-8222's BMS will refuse to boot, treating the pack as over-discharged and potentially damaged. Connect the device to mains power and leave it on the charger for at least 30 minutes before attempting to power on. This allows the charge IC to trickle-charge the cell back above the BMS recovery threshold. Once voltage climbs above 10.5V, the device will power on normally.