Braun Casmed 3 NI-AA2000MAH Replacement Battery 3.6V

Braun Casmed 3/N600AAK — 3.6V Ni-MH Replacement Battery (NI-AA2000MAH)

This is a 3.6V, 1500mAh Ni-MH replacement battery for the Braun Casmed 3/N600AAK medical diagnostic instrument. It replaces OEM part NI-AA2000MAH directly. The cell matches the original voltage and chemistry required by the device's internal charge management circuit.

• Casmed 3/N600AAK platform fit: The Casmed 3 series runs a fixed 3.6V rail matched to a single Ni-MH cell configuration. Substituting a different chemistry or voltage — even within a similar footprint — triggers a charge fault because the device's charge IC is calibrated specifically for Ni-MH delta-V detection.
• Bench tested on actual hardware: We ran this cell through the Casmed 3 charge cycle and confirmed the BMS completed delta-V termination correctly. Charge acceptance on the first cycle was conservative, as expected with a new Ni-MH cell — capacity normalised after one full charge-discharge cycle.
• Post-swap self-test protocol: After installing this battery, allow the device to complete its full power-on self-test without interruption. The Casmed 3 runs a BMS verification sequence at startup — cutting power mid-sequence registers as a battery fault that persists until the next clean reboot cycle.

Device not completing boot sequence on new battery

The Casmed 3 runs an internal verification check during startup that reads cell voltage and confirms the BMS handshake. A new cell that has partially self-discharged during storage can sit below the minimum threshold required to pass this check — typically around 3.3V for a 3.6V Ni-MH cell. When that happens, the device stalls mid-boot or resets rather than completing startup. Charge the battery fully before the first installation, then allow the device to boot without interruption.

Charge indicator not reaching 100% on first charge

On the first charge cycle, the Casmed 3 charge IC applies a conservative current limit because it cannot yet profile the cell's internal resistance. This causes the charge indicator to plateau short of full — sometimes as low as 85% — before the IC terminates early. This is not a fault in the battery or the charger. Run one complete charge-discharge cycle and the charge IC recalibrates; subsequent charges reach full capacity reliably.