Laerdal Resusci Baby QCPR 7.4V Replacement Battery 161-40023

Laerdal Resusci Baby QCPR — 7.4V Li-ion Replacement Battery (161-40023)

This 7.4V 3400mAh Li-ion battery replaces the OEM pack in the Laerdal Resusci Baby QCPR manikin. It powers the compression quality feedback electronics — the system that tracks depth, rate, and hand position during CPR training. Match OEM part number 161-40023 before ordering.

• Resusci Baby QCPR feedback system: The QCPR platform runs a continuous BMS handshake between the battery and the feedback board. The voltage rail, connector pinout, and cell chemistry must match exactly — mismatched cells cause the feedback module to drop offline mid-session without warning.
• Bench tested on actual hardware: We cycled this pack through full charge and discharge on the QCPR platform, confirmed BMS communication stayed active, and verified the compression sensor data stream remained uninterrupted throughout the test load.
• Post-swap self-test protocol: After installing this battery, let the manikin complete its full power-on self-test without interrupting the boot sequence. The BMS runs a chemistry verification at startup — cutting power during this window logs a false battery fault that persists until the next clean reboot.

Why the QCPR manikin won't complete its boot sequence after a battery swap

The Resusci Baby QCPR runs a multi-stage BMS initialisation at power-on that checks cell voltage, internal resistance, and chemistry signature against stored OEM thresholds. A new cell that hasn't completed its first full charge cycle may sit slightly below the voltage floor the BMS expects, which stalls the boot at the self-test stage. This isn't a fault with the battery — it's the device's safety logic protecting the compression sensor circuit. Charge the pack fully before first installation, then allow the boot sequence to complete without interruption.

Low battery alarm triggers immediately after confirmed full charge

This happens because the device's charge IC applies a conservative voltage ceiling on an unfamiliar cell during the first charge cycle, and the resulting resting voltage can fall just inside the alarm threshold. The BMS hasn't yet calibrated its state-of-charge model to the new cell's actual capacity curve. Run one complete charge-to-discharge-to-charge cycle before using the manikin in a training session. After that conditioning cycle, resting voltage stabilises above 8.0V and the alarm clears.