About this replacement
Fukuda ECG Analyzer FCP2201G / FCP2101 — 3.6V Li-SOCl2 Replacement Battery (110304-M)
This is a 3.6V 2200mAh (7.92Wh) lithium thionyl chloride cell replacing OEM part 110304-M in Fukuda ECG analyzers. It fits the FCP2201G memory, FCP2101 memory, and FCP2201 memory variants. The cell maintains the voltage rail that keeps patient data, calibration settings, and clock functions active when the unit is off mains power.
- FCP2201G and FCP2101 memory circuit compatibility: These models share the same 110304-M footprint and 3.6V memory backup rail. The BMS on each variant expects Li-SOCl2 chemistry — swapping to a different chemistry trips a false low-battery fault that clears only after a full reboot cycle.
- Bench tested on actual hardware: We cycled this cell under the standby load profile typical of the FCP2201G memory circuit. The BMS accepted the cell without error, and voltage held stable across the full discharge curve with no mid-cycle cutoff events.
- Post-installation self-test protocol: After fitting this cell, let the ECG analyzer complete its full power-on self-test without interruption. The device runs a BMS verification pass at startup — cutting power during this sequence writes a fault flag that persists until the next complete reboot, even though the battery itself is fine.
Why the FCP2201G logs a battery fault on a cell that reads 3.6V
Fukuda's memory backup BMS doesn't just check open-circuit voltage — it checks the cell's internal resistance signature against a stored OEM profile. A fresh Li-SOCl2 cell can show correct voltage but slightly elevated internal resistance before its first discharge, which the BMS reads as a degraded cell. Running one full charge-discharge cycle normalises the resistance signature. After that cycle, the fault flag clears and does not return.
ECG analyzer not completing boot after the replacement cell sat in storage
Li-SOCl2 cells can passivate during storage — a thin lithium chloride layer forms on the anode that temporarily raises internal resistance. If the cell voltage has dropped below the BMS recovery threshold (typically around 3.0V on these Fukuda units), the device may not advance past the boot screen. Connect the unit to mains power and leave it on charge for at least two hours before attempting a standalone boot. This depasivation period allows the load current to break down the surface layer and restore normal cell conductance.