Bionet EKG3000 Replacement Battery 12V 4200mAh Ni-MH

Bionet EKG3000 — 12V Ni-MH Replacement Battery (GPHC132MOT)

This is a 12V 4200mAh Ni-MH replacement battery for the Bionet EKG3000 portable electrocardiograph. It also fits the FC-1400 TwinView Fetal Monitor and CardioCare 2000 ECG. Capacity matches the OEM specification at 50.4Wh.

• EKG3000, FC-1400, and CardioCare 2000 compatibility: These three Bionet units share the same 12V Ni-MH battery bay, connector pinout, and BMS communication protocol. One cell format covers the full platform without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the EKG3000. The BMS accepted the cell without fault codes, completed its self-test handshake, and held stable voltage across the full load profile of the ECG acquisition circuit.
• Post-swap power-on sequence: After installing this battery, allow the device to complete its full power-on self-test without interruption. The Bionet BMS runs a chemistry verification step at startup — cutting power during this window logs a battery fault that persists until the next clean reboot cycle.

Why the EKG3000 reports a battery fault on a brand-new cell

The EKG3000 BMS stores a learned capacity profile from the previous cell. When a new Ni-MH cell is installed, the BMS compares its first charge reading against that stored profile and can flag a mismatch as a fault. This is not a defective cell — it is the BMS running its validation pass against unfamiliar data. One full charge-to-discharge cycle clears the stored profile and lets the BMS register the new cell's baseline. After that cycle, the fault clears and the battery indicator reads accurately.

Charge indicator stalls below 100% on the first charge

On first charge, the EKG3000 charge IC applies a conservative current limit when it cannot confirm the cell's internal resistance history. This causes the charge indicator to plateau at 80–90% and stall. The cell is still receiving charge — the IC is running a slow top-off pass rather than terminating normally. Let the charge cycle run to natural termination without unplugging early. After one complete cycle, the charge IC recalibrates its delta-V cutoff to the new cell and subsequent charges reach 100% and terminate correctly.