About this replacement
Schiller Cardiovit ECG AT3 — 9.6V Ni-MH Replacement Battery (88888534)
This is a 9.6V, 1500mAh Ni-MH battery (OEM part no. 88888534) for the Schiller Cardiovit ECG AT3 and E-1573 portable electrocardiographs. It slots into the battery compartment and restores cordless operation during patient examinations and ambulatory ECG recording. Voltage and connector match the original specification exactly.
- AT3 and E-1573 compatibility: Both models run the same 9.6V power rail, use the same physical battery bay, and share the same BMS handshake protocol — one cell SKU covers both units without modification.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge on the AT3 platform. The BMS accepted the new cell on the first charge cycle, and the charge indicator advanced through all stages without fault flags.
- Post-swap self-test protocol: After fitting this battery, let the AT3 complete its full power-on self-test sequence without interruption. The device runs a BMS verification routine at startup — cutting power during this sequence can register a false battery fault that persists until the next full reboot.
Why the AT3 flags a battery fault after a confirmed full charge
The Cardiovit AT3 BMS applies a voltage threshold check calibrated to an aged OEM cell's charge profile. A new Ni-MH cell has a slightly different voltage rise curve during the first few cycles, and the BMS can misread this as an undercharged or faulty pack. The fix is one complete charge-discharge cycle run entirely inside the device before clinical use. After that cycle, the BMS recalibrates its threshold and clears the fault flag on the next charge.
Device will not power on after the replacement cell sat in shipping or storage
Ni-MH cells self-discharge during transit and storage. If the resting voltage drops below the AT3's BMS recovery threshold — typically around 8.4V for a 9.6V eight-cell pack — the device will not boot and shows no response on the power button. Place the battery on charge immediately after unpacking and leave it for a full uninterrupted cycle. Once voltage climbs back above the BMS recovery floor, the device will power on normally and complete its self-test.