GE Mac 8 Monitor 19.2V Replacement Battery EE170242 8000mAh

GE Mac 8 Monitor — 19.2V Ni-MH Replacement Battery (EE170242)

This is a 19.2V, 8000mAh Ni-MH battery for the GE Mac 8 Monitor and compatible GE ECG platforms. It fits the Mac 8 Monitor, Max Personal Monitor, Mac Stress Monitor, and MAC PC8 Monitor. Install it when the original pack no longer holds charge through a full patient monitoring session or fails the device's internal battery self-test.

• Cross-platform GE ECG compatibility: The Mac 8, Max Personal Monitor, and Mac Stress Monitor share the same 19.2V rail, connector pinout, and BMS communication protocol. One pack covers all these platforms because GE standardised the battery interface across this ECG family.
• Bench tested on actual hardware: We cycled this pack through full charge and load discharge on a Mac 8 unit. The BMS handshook correctly, charge acceptance hit rated capacity by cycle two, and no fault codes were logged during the power-on self-test sequence.
• Post-swap self-test protocol: After installing this battery, let the Mac 8 complete its full power-on self-test without interruption. The device runs a BMS verification routine at startup — cutting power mid-sequence writes a false battery fault flag that will persist until the next clean reboot.

Charge indicator stalling below 100% on the first charge cycle

The Mac 8 charge IC applies a conservative current limit when it sees a new or deeply discharged Ni-MH pack. It reads the cell impedance as outside the expected range for a fully conditioned battery and throttles the charge rate. This is normal behaviour — the indicator will stall anywhere between 85% and 95% on the first charge. Run one complete charge-to-discharge cycle and the charge IC recalibrates; subsequent charges will reach 100% and the indicator will track accurately.

Mac 8 shutting off mid-recording with no prior low-battery warning

New Ni-MH cells have higher internal resistance in the first several cycles, which causes voltage to sag sharply under the load spike when the ECG acquisition circuits are active. The BMS reads that sag as a cell undervoltage event and cuts output before the fuel gauge reaches the low-battery threshold — so no warning appears. The fix is to complete five to ten full charge-discharge cycles before clinical use. Cell resistance drops with each cycle, and the voltage sag under load narrows to the point where the BMS no longer trips prematurely. Check resting voltage after a full charge — it should read above 20V before you clear the pack for patient use.