GE Marquette MAC1000 Replacement Battery 18V 2000mAh

GE Marquette MAC1000 Series — 18V Ni-MH Replacement Battery (30344270)

This is an 18V 2000mAh Ni-MH replacement battery for the GE Marquette MAC1000 electrocardiograph. It fits the MAC1000, MAC1100, MAC1200, and MAC1500 portable ECG machines used in clinical and hospital settings. The battery slots into the same bay as the original 30344270 cell and connects to the same BMS interface.

• MAC1000 series compatibility: The MAC1000, MAC1100, MAC1200, and MAC1500 share the same 18V battery bay, connector pinout, and BMS communication protocol. Swapping between models in this family does not require any configuration change — the battery handshake is identical across the series.
• Bench tested on actual hardware: We ran this cell through the MAC1000 charge cycle and monitored BMS response at startup. The charge IC applied a conservative current limit on the first charge, which is normal Ni-MH behaviour — the cell reached rated capacity after the first full discharge-recharge cycle.
• First-use self-test cycle: After installing this battery, allow the MAC1000 to complete its full power-on self-test without interruption. The device runs a BMS verification sequence at boot — cutting power during this step logs a false battery fault that persists until the unit completes a clean reboot with the battery fully seated.

MAC1000 charge indicator stalling before 100% on first charge

The MAC1000 charge IC applies a tighter current ceiling when it reads the cell as new or unverified. This is intentional — the device protects against overcharge on cells it has not yet characterised. The indicator typically stalls between 85% and 95% on the first charge, then completes normally on the second. Run one full discharge-recharge cycle before relying on the charge readout for clinical scheduling.

Device not completing boot sequence after battery swap

If the MAC1000 stalls at the boot screen after a battery replacement, the BMS has not cleared its previous fault state. This happens when the old battery was removed while the device was mid-cycle or when the new cell voltage is below the BMS recovery threshold after storage. Check resting voltage at the battery terminals — it should read above 15V before insertion. If it reads lower, place the cell on charge for at least two hours before attempting boot.