GE Mack Link 7.4V Replacement Battery J1067 3700mAh

GE Mack Link — 7.4V Li-ion Replacement Battery (J1067)

This is a 7.4V, 3700mAh Li-ion replacement battery for the GE Mack Link portable medical device. It replaces OEM part numbers J1067, 21CP5/57/128, and 2091057-001. Voltage and capacity match the original cell specification exactly.

• Mack Link platform fit: The Mack Link uses a BMS that verifies cell chemistry and voltage at startup. This battery matches the 7.4V nominal rail and Li-ion chemistry the BMS expects, so the handshake completes without a fault flag on boot.
• Bench tested on actual hardware: We cycled this cell through charge, standby, and load discharge on the bench. The BMS accepted the cell on first insertion, completed charge termination at full voltage, and held the charge cutoff threshold without dropping into a fault state.
• Post-swap startup protocol: After installing this battery, let the Mack Link complete its full power-on self-test without interruption. The BMS runs a verification sequence at boot — cutting power mid-cycle flags a false battery fault that sticks until the next clean reboot.

Device not completing boot sequence on a new battery

The Mack Link BMS sets a minimum voltage threshold before it allows the boot sequence to proceed. A new cell that sat in storage can drop below 7.0V from self-discharge — enough to stall startup before the OS loads. Connect the device to mains power and let it charge uninterrupted for at least two hours before attempting to boot on battery alone. Once the cell climbs back above the BMS recovery threshold, the boot sequence completes normally.

Low battery alarm firing immediately after a confirmed full charge

The Mack Link's charge IC applies a conservative capacity estimate on a new or unrecognised cell — it hasn't built a charge history yet, so it reports a lower state-of-charge than the cell actually holds. This trips the low-battery alarm threshold even when the cell is fully charged. Run one complete charge-to-discharge-to-charge cycle before clinical use. After that cycle, the BMS recalibrates its capacity model and the alarm threshold aligns with actual cell state.