About this replacement
OSEN ECG-8110 / ECG-8110A — 12V Ni-MH Replacement Battery (BF4500AH10)
This is a 12V 2000mAh Ni-MH replacement battery for the OSEN ECG-8110 and ECG-8110A portable electrocardiograph. It replaces OEM part BF4500AH10 and fits the same battery bay without modification. Capacity is rated at 24Wh per the product specification.
- ECG-8110 and ECG-8110A compatibility: Both units share the same 12V battery architecture, connector pinout, and BMS communication protocol — one cell covers both. The voltage rail and physical dimensions (83.90 × 43.00 × 33.60mm) match the OEM cavity exactly.
- Bench tested on actual hardware: We ran charge-discharge cycles on the ECG-8110 platform. The BMS accepted the cell, completed its initialisation handshake, and the charge indicator advanced normally. No fault codes were triggered across repeat cycles.
- Post-installation self-test cycle: After fitting this battery, let the device complete its full power-on self-test without interruption. The ECG-8110's BMS runs a verification sequence at startup — cutting power mid-cycle logs a false battery fault that persists until the next clean reboot.
Why the ECG-8110 flags a battery fault on the first boot after a cell swap
The ECG-8110 uses a BMS that stores a chemistry profile from the previous cell. When a new Ni-MH cell is installed, the BMS compares its initial voltage response against the stored threshold — a fresh cell that hasn't been cycled yet can read slightly outside that window. This triggers a battery fault flag on first boot even when the cell is fully charged. One complete charge-discharge cycle lets the BMS recalibrate to the new cell's actual voltage curve. After that cycle, the fault clears and does not return.
Charge indicator not reaching 100% on the first charge
On the first charge after installation, the ECG-8110's charge IC applies a conservative current limit to an unrecognised cell — it terminates early rather than risk overcharging an unknown chemistry state. This is not a cell fault. Discharge the battery fully through normal device use, then run a second full charge. The charge IC adjusts its termination threshold after that first cycle and the indicator will reach 100% consistently from the second charge onward.