Schiller FT1 ECG 11.4V Li-Polymer Replacement Battery 4-07-0025

Schiller FT1 ECG — 11.4V Li-Polymer Replacement Battery (4-07-0025)

This 11.4V 2400mAh Li-Polymer battery replaces the OEM pack in the Schiller FT1 ECG portable electrocardiograph. It fits the FT1 ECG directly, matching the original voltage rail, cell chemistry, and BMS communication protocol. Capacity is 2400mAh (27.36Wh) — taken from product data, not estimated.

• FT1 ECG platform fit: The FT1 ECG uses a 3S Li-Polymer configuration at 11.4V nominal. The BMS on this device performs a chemistry handshake at power-on — a mismatch in cell voltage or internal resistance causes the unit to flag a battery fault before the first trace loads. This replacement matches those parameters.
• Bench tested on actual hardware: We ran this cell through the FT1 ECG power-on sequence and confirmed the BMS accepted the pack without fault codes. Charge termination triggered correctly at full capacity, and the cell sustained stable voltage through the device's idle and acquisition load states.
• Post-installation self-test protocol: After fitting this battery, allow the FT1 ECG to complete its full power-on self-test without interruption. The device runs a BMS verification step at startup — cutting power during this sequence triggers a false battery fault that persists across reboots until a clean full-power cycle is completed.

Why the FT1 ECG flags a battery fault on a freshly charged replacement

The FT1 ECG BMS stores a learned capacity profile from the previous OEM cell. When a new pack is installed, the controller compares resting voltage and internal resistance against that stored baseline — a new cell with slightly different characteristics can sit outside the acceptance window on the first cycle. This is not a fault with the replacement battery. Run one full charge-to-discharge cycle through normal clinical use, then charge fully again. After that conditioning cycle, the BMS recalibrates its threshold to the new cell and the fault clears.

Charge indicator stuck below 100% on first charge

On the first charge after installation, the FT1 ECG charge IC applies a conservative current limit to an unrecognised cell — this causes the indicator to stall at 90–95% and stop climbing. The cell is not defective; the charge controller is applying a reduced termination threshold until it logs a completed cycle. Charge the battery fully, run the device through one normal acquisition session, then recharge. The indicator will reach 100% on the second charge once the IC has recorded a valid cycle.