About this replacement
Heine mPack / mPack LL — 7.4V Li-ion Replacement Battery (X-007.99.676)
This 7.4V 5200mAh Li-ion battery replaces the original power cell in the Heine mPack and mPack LL portable diagnostic systems. These are compact clinical examination devices used for illuminated inspections in healthcare settings. Voltage and capacity match the OEM specification exactly — 7.4V, 5200mAh (38.48Wh).
- mPack and mPack LL compatibility: Both variants share the same battery bay geometry, connector pinout, and 7.4V supply rail. The BMS communication protocol is identical across the two models, so one cell covers both without modification.
- Bench tested on actual hardware: We cycled this cell through the mPack charge controller and monitored BMS handshake behaviour. The protection circuit responded correctly to charge termination, over-discharge cutoff, and temperature limits across multiple cycles.
- First-use power-on sequence: After installing this battery, allow the mPack to complete its full power-on self-test without interruption. The device runs a BMS verification routine at startup — cutting power during this sequence triggers a false battery fault that persists until the next clean reboot.
Why the mPack reports low battery immediately after a confirmed full charge
The mPack's charge IC applies conservative acceptance thresholds calibrated to the OEM cell's charge history. A new replacement cell has no cycle data, so the BMS flags it as below threshold on the first power-on. This is not a fault with the cell — it clears after one complete charge-discharge cycle. Run the device down to auto-shutoff, recharge fully to 8.4V, and the indicator will read correctly from that point forward.
Device will not power on after the replacement cell sat in storage
Li-ion cells self-discharge during storage. If the cell voltage has dropped below approximately 2.5V per cell (5.0V pack total), the mPack's BMS will not allow power-on — this is a deep-discharge lockout, not a dead battery. Connect the original Heine charger and leave it for a minimum of 30 minutes without attempting to power the device on. The charge IC will trickle-charge the pack back above the BMS recovery threshold, after which normal charging resumes.