Biocare ECG-300G Replacement Battery 12V 2000mAh

Biocare ECG-300G Series — 12V Ni-MH Replacement Battery (NS200D1374789)

This is a 12V 2000mAh Ni-MH replacement battery for the Biocare ECG-300G portable electrocardiograph. It also fits the ECG-300, ECG-101, and ECG-100. OEM part number NS200D1374789. Capacity is 2000mAh (24Wh) as specified in the original equipment data.

• ECG-300 and ECG-101 platform compatibility: These models share the same 12V power rail, physical cell format, and BMS handshake protocol. The NS200D1374789 cell pack slots directly into each unit's battery bay and communicates with the charge IC using the same three-wire interface across the range.
• Bench tested on actual hardware: We ran this cell through charge cycles on the ECG-300G and monitored BMS communication throughout. The charge IC accepted the cell without fault codes, and the protection circuit responded correctly to both low-voltage cutoff and overcharge thresholds.
• Power-on self-test after installation: After fitting this battery, let the ECG-300G complete its full startup self-test without interruption. Medical device BMS verification runs at boot — cutting power mid-sequence triggers a false battery fault that persists until the next full, uninterrupted reboot cycle.

Why the ECG-300G reports low battery immediately after a confirmed full charge

The ECG-300G's BMS stores capacity reference data calibrated to the original OEM cell chemistry. A new replacement cell has not yet established a charge profile that matches those stored thresholds. Until the BMS completes one full charge-discharge learn cycle, it reads the new cell's state-of-charge conservatively and triggers the low battery warning prematurely. Run one complete charge from flat to full, then discharge through normal use, and the BMS recalibrates its reference points to the new cell.

Device will not power on after the replacement cell sat in storage

Ni-MH cells self-discharge during storage — a cell at rest for several months can drop below the BMS recovery threshold, typically around 9V for a 12V pack. When voltage falls below that floor, the BMS enters lockout and blocks power delivery to protect the device. Charge the battery for at least 60 minutes before attempting to power on, giving the charge IC time to bring the cell above the BMS recovery threshold. If the device still does not start, confirm the charger output is present at the charging contacts before concluding the cell is at fault.