About this replacement
Nihon Kohden Cardiolife ECG-9320 Series — 12V Sealed Lead Acid Replacement Battery (LC-S2912NK)
This is a 12V 2900mAh sealed lead-acid replacement battery for the Nihon Kohden Cardiolife ECG-9320 defibrillator series. It fits the ECG-9320, TEC-7431, TEC-7511, and TEC-7521 platforms. The OEM part number is LC-S2912NK.
- Cardiolife TEC and ECG-9320 platform fit: These models share the same 12V SLA bay, connector pinout, and BMS handshake protocol. One battery revision covers the full range listed above without modification.
- Bench tested on actual hardware: We cycled this cell under the ECG-9320 charge profile and confirmed the BMS accepted the cell, completed the charge handshake, and held voltage within the device's operating window across repeated discharge cycles.
- Post-installation self-test protocol: After fitting this battery, allow the Cardiolife unit to complete its full power-on self-test without interruption. The device runs a BMS verification at startup — cutting power mid-sequence triggers a false battery fault that persists until the next full reboot.
Low battery alarm immediately after a confirmed full charge
The Cardiolife's BMS compares the new cell's resting voltage against a threshold calibrated to the OEM cell's charge curve. A fresh SLA cell often presents a resting voltage slightly below that threshold on the first cycle, triggering the alarm even when the cell is fully charged. This is a calibration mismatch, not a faulty battery. Run one complete charge-discharge cycle on the device before drawing any conclusion about battery health. After that cycle the BMS re-evaluates the cell and the alarm clears at approximately 12.6–12.8V resting voltage.
Device will not power on after the replacement cell sat in storage
Sealed lead-acid cells self-discharge at roughly 3–5% per month. If this battery was stored before installation and voltage dropped below 10.5V, the Cardiolife's BMS will refuse to initialise — the device shows nothing on power-on. Connect the unit to mains and leave it on charge for a full uninterrupted cycle, typically 24 hours. The charger will apply a recovery trickle below the BMS threshold before stepping up to bulk charge. Once resting voltage recovers above 11V the device will boot normally.