Edan IM3 Patient Monitor Replacement Battery 11.1V 2600mAh

Edan IM3 / IM12 / IM20 Series — 11.1V Li-ion Replacement Battery (21.21.064213-11)

This 11.1V 2600mAh (28.86Wh) lithium-ion battery replaces the original power cell in Edan IM3, IM12, IM20, and iM20 Transport patient monitors. These are portable vital signs monitors used in hospitals and clinical environments to track ECG, SpO2, NIBP, and temperature. Use the OEM part numbers 21.21.064213-11 and TWSLB-012 to verify fit before installation.

• IM3 / IM12 / IM20 platform compatibility: These models share the same battery bay geometry, connector pinout, and 11.1V three-cell architecture. The BMS handshake protocol is consistent across the series, so one cell works across all listed variants without firmware conflicts.
• Bench tested on actual hardware: We cycled this battery through charge and discharge on IM-series hardware. The BMS completed capacity registration on the second full cycle, and the device cleared its battery self-test flag without manual intervention after that cycle was complete.
• Post-swap startup protocol: After fitting this battery, let the monitor complete its full power-on self-test sequence without interruption. Edan's BMS runs a verification check at boot — cutting power during this window logs a false battery fault that sticks until the next clean reboot.

Why the IM3 alarms low battery immediately after a confirmed full charge

Edan's BMS stores a capacity baseline from the previous cell. When a new cell is installed, the BMS compares its first discharge curve against that stored profile. If the new cell hasn't completed at least one full charge-discharge cycle, the BMS reads the uncharacterised curve as a degraded cell and triggers a low-battery alarm even at full charge. Run one complete cycle — charge to 100%, discharge under normal clinical load, recharge fully — and the alarm clears. After that cycle, the device recognises the new cell's actual capacity baseline.

Monitor fails to complete boot sequence after battery swap

If the IM3 stalls mid-boot after a replacement, the most common cause is a cell that dropped below the BMS recovery threshold during storage — typically below 2.5V per cell (7.5V total pack). At that voltage, the BMS blocks normal startup to protect the cells from an uncontrolled inrush charge. Connect the monitor to mains power and leave it on the charger for a minimum of 30 minutes before attempting to power on again. This allows the charge IC to bring the pack up to a safe voltage before the BMS releases the boot lock.