Edan SD5 ECG Replacement Battery 7.2V 2000mAh B0402100

Edan SD5 / SD6 — 7.2V Ni-MH Replacement Battery (B0402100)

This 7.2V, 2000mAh Ni-MH battery replaces the OEM power cell in the Edan SD5 and SD6 portable 12-lead ECG systems. It matches the original B0402100 and FSNH-6XAA2000 part numbers. Both models share the same voltage rail, connector, and BMS handshake, so one cell covers either unit.

• SD5 and SD6 compatibility: Both ECG units run the same 7.2V pack architecture with an identical connector and BMS communication protocol. The charge IC on each device reads cell chemistry the same way, so this replacement works in either chassis without hardware modification.
• Bench tested on actual hardware: We ran this cell through a full charge-discharge cycle on an SD5 unit and confirmed the BMS accepted the pack, completed its initialisation sequence, and reported state-of-charge correctly through the device display without triggering a fault code.
• Post-swap startup protocol: After installing this battery, let the SD5 or SD6 complete its full power-on self-test without interruption. The BMS runs a verification pass at startup, and cutting power during that sequence writes a false battery fault that persists until the next clean reboot.

Why the SD5 reports a battery fault after a confirmed full charge

The SD5 BMS stores a learned capacity baseline from the previous cell. When a new Ni-MH pack is installed, that baseline does not match the fresh cell's charge curve, so the device flags a mismatch fault even when the battery is fully charged. One complete charge-discharge cycle resets the BMS learn register to the new cell's profile. Until that cycle runs, the fault indicator may persist regardless of actual charge state. Run the cycle before placing the unit back into clinical rotation.

Charge indicator stuck below 100% on the first charge after swap

The SD5 charge IC applies a conservative current limit when it detects a cell with no prior cycle history. This causes the charge percentage to stall — typically between 80% and 90% — on the first pass. The cell is not defective. A second full charge cycle from a low state lets the IC recalibrate its termination threshold. After that second cycle, the indicator should reach 100% and hold. Discharge the unit to the low-battery warning before starting the second charge.