Biolight M8000 Patient Monitor Replacement Battery 11.1V 2600mAh

Biolight M8000 Series — 11.1V Li-ion Replacement Battery (LI1104C)

This 11.1V 2600mAh Li-ion battery replaces part number LI1104C in the Biolight M8000, M9000, M9000A, and M9500 patient monitors. It covers the full series that shares the same voltage rail and connector specification. Capacity is 2600mAh (28.86Wh), matching the original specification.

• M8000 through M9500 compatibility: These models run the same 11.1V three-cell Li-ion architecture with an identical BMS handshake protocol. The connector pinout and communication bus are consistent across the series, so one cell pack covers all listed variants.
• Bench tested on actual hardware: We cycled this battery through full charge and discharge on the M8000 platform. The BMS authenticated correctly, the charge IC accepted the cell without triggering a fault code, and the monitor completed its power-on self-test without interruption.
• Post-swap self-test protocol: After installing this battery, let the monitor complete its full power-on self-test without interruption. The BMS runs a verification sequence at startup — cutting power during this window logs a false battery fault that persists across sessions until the device is fully rebooted and the sequence is allowed to finish.

Why the M8000 flags a battery fault on the first boot after installation

The M8000 BMS checks cell authentication and voltage signature at every cold start. A new cell that has not completed one full charge-discharge cycle may present a voltage profile that sits outside the BMS's learned acceptance window. This triggers a battery fault flag even though the cell is functional. Running one complete charge cycle — from the monitor's charge IC, not an external charger — resets the BMS baseline and clears the flag on the next boot.

Charge indicator stalls below 100% on first charge

The M8000 charge IC applies a conservative current limit when it detects a new or previously deep-discharged cell. This causes the charge progress indicator to appear stuck at 95–98% for an extended period. The IC is still working — it has shifted to trickle mode to top-balance the cells safely. Leave the monitor on charge until the indicator confirms completion; removing it early leaves the top cell below the 4.2V target and the BMS will report insufficient capacity on the next self-test.