About this replacement
Fukuda FCB-220IU / ECG Cardimax Series — 12V Ni-MH Replacement Battery (BF300SCAH10)
This is a 12V 3000mAh Ni-MH replacement battery for the Fukuda FCB-220IU and ECG Cardimax FCP-2201U, FCP-2201G, and FCP-2101 portable ECG units. It replaces OEM part BF300SCAH10 and slots into the same battery compartment without modification. Voltage and capacity match the original specification at 12V and 36Wh.
- Cardimax FCP series compatibility: The FCB-220IU and FCP-2201U, FCP-2201G, and FCP-2101 share the same 12V battery bay, connector pinout, and BMS handshake protocol — one cell fits the entire group without adapter or firmware change.
- Bench tested on actual hardware: We ran this cell through charge and load cycles on a Cardimax-class test rig. The BMS accepted the new Ni-MH cell without fault codes, and the charge IC completed its full trickle-to-termination cycle correctly.
- Post-swap self-test requirement: After installing this battery, let the device complete its full power-on self-test without interruption. Fukuda ECG units run a BMS verification routine at startup — cutting power during that sequence logs a false battery fault that persists until the next clean reboot.
Why the ECG Cardimax alarms low battery immediately after a confirmed full charge
The Cardimax BMS stores a learned capacity profile from the previous cell. A new Ni-MH replacement starts with no charge history, so the BMS compares its first discharge curve against the old profile and flags a mismatch as a low-battery condition. This is not a fault with the cell — it is the BMS running its learn cycle. One complete charge-discharge-recharge cycle rewrites the profile and clears the alarm. Do not use the unit clinically until that cycle is finished and the alarm is gone.
Device will not power on after the replacement battery sat in storage
Ni-MH cells self-discharge at roughly 1–2% per day in storage. A cell that has sat for several months can drop below the BMS recovery threshold — typically around 10V on a 12V Ni-MH pack — and the device will show no response at power-on. Place the battery on a standalone Ni-MH charger and bring voltage above 11V before reinserting it. Once the cell clears the recovery threshold, the device will power on normally and the BMS will accept a full charge cycle.