Physio-Control LUCAS 2 Replacement Battery 25.9V 3000mAh

Physio-Control LUCAS 2 / LUCAS 3 — 25.9V Li-Polymer Replacement Battery (100947-00)

This 25.9V, 3000mAh Li-Polymer battery replaces OEM part numbers 100947-00, 16201-00, and 11576-000080 in the Physio-Control LUCAS 2 and LUCAS 3 automated chest compression devices. The LUCAS platform drives a motorized piston mechanism that delivers continuous mechanical CPR — a task that draws hard, repetitive current pulses from the battery pack. Voltage, connector, and BMS communication must match exactly for the device to pass its power-on self-test.

• LUCAS 2 and LUCAS 3 compatibility: Both generations share the same 25.9V battery architecture, connector pinout, and BMS handshake protocol. The pack communicates state-of-charge data back to the device controller — a mismatch in cell chemistry or communication profile causes the device to flag a battery fault before the piston motor ever activates.
• Bench tested on actual hardware: We ran this pack through the LUCAS power-on self-test sequence and full piston actuation cycles. The BMS reported state-of-charge correctly, the device completed its self-test without fault codes, and the compression motor drew current within the expected operating envelope across repeated cycles.
• Post-installation self-test protocol: After fitting this battery, let the LUCAS complete its full power-on self-test cycle without interrupting power. Medical device BMS verification runs at startup — cutting power mid-sequence causes a persistent false battery fault that will not clear until the device completes a clean, uninterrupted reboot from a fully charged pack.

Why the LUCAS 2 flags a battery fault after a confirmed full charge

The LUCAS BMS applies a chemistry-specific threshold during its self-test — it checks not just voltage but the cell's internal resistance profile. A new Li-Polymer pack has a slightly elevated resistance on its first few cycles before the cells condition. This can push the reading just outside the OEM acceptance window, triggering a low-battery or fault flag even when the pack is fully charged. One complete charge-discharge cycle through the device normalises the resistance profile and clears the fault on subsequent self-tests.

LUCAS 3 will not power on after battery sat in storage

Li-Polymer cells self-discharge over time — if a replacement pack has been on the shelf for several months, its resting voltage may fall below the LUCAS BMS recovery threshold, typically around 20V for a 25.9V nominal pack. Below that threshold, the BMS locks the discharge path and the device shows no response on the power button. Place the battery on a compatible Li-Polymer charger and allow a full charge cycle to bring cell voltage back above the recovery floor before attempting to install and power on the device.