About this replacement
Laerdal Resusci Baby QCPR — 7.4V Li-ion Replacement Battery (161-40023)
This 7.4V Li-ion cell is a direct replacement for the Laerdal Resusci Baby QCPR training manikin. At 2600mAh (19.24Wh), it powers the manikin's electronic CPR feedback and sensor systems. It matches the OEM part number 161-40023 and fits the QCPR platform's battery bay and connector.
- Resusci Baby QCPR feedback electronics: The QCPR platform runs compression-depth sensors, airway feedback, and wireless data transmission from a single 7.4V supply rail. This cell meets that voltage requirement and carries the BMS handshake the device expects at startup.
- Bench tested on actual hardware: We cycled this cell through the QCPR's power-on self-test sequence and confirmed the BMS passed state-of-charge verification without triggering a false fault. Load draw during active training simulation stayed within the cell's rated discharge envelope throughout testing.
- Post-swap startup protocol: After installing this battery, let the Resusci Baby QCPR complete its full power-on self-test without interruption. The device's BMS runs a chemistry verification at boot — cutting power mid-sequence writes a battery fault flag that persists until the next clean reboot.
Why the Resusci Baby QCPR alarms low battery immediately after a confirmed full charge
The QCPR's charge IC applies a conservative state-of-charge threshold on first contact with a new cell. The BMS compares internal resistance and open-circuit voltage against a learned baseline from the previous cell — a new cell hasn't established that baseline yet. This mismatch triggers the low-battery flag even when the cell is sitting at full charge. One complete charge-discharge cycle resets the learned baseline and clears the alarm.
Resusci Baby QCPR not powering on after the battery sat in storage
Li-ion cells self-discharge at roughly 2–3% per month in storage. If the cell voltage drops below approximately 2.5V per cell (5.0V pack), the QCPR's BMS enters deep-discharge lockout and will not allow a normal boot. The fix is a slow pre-charge using a compatible Li-ion charger that supports recovery mode — this trickle-charges the pack back above the 6.0V threshold the BMS needs before it will permit a full charge cycle. Once the pack reads above 6.0V, connect to the standard Laerdal charger and run a full charge before powering the manikin on.