About this replacement
Heine mPack / mPack LL — 7.4V Li-ion Replacement Battery (X-007.99.676)
This 7.4V 6800mAh (50.32Wh) lithium-ion battery replaces the OEM pack in the Heine mPack and mPack LL portable diagnostic systems. It fits both variants of the mPack platform and uses the same connector and BMS communication protocol as the original. Cross-compatible with OEM part numbers X-007.99.675, X-07.99.675, and X-07.99.676.
- mPack and mPack LL compatibility: Both models share the same battery bay geometry, voltage rail, and BMS handshake protocol. A single cell type serves both platforms because Heine standardised the pack interface across the mPack generation — the LL variant draws slightly higher peak current through its illumination chain, but the BMS cutoff threshold is identical.
- Bench tested on actual hardware: We cycled this cell through the mPack charge-discharge sequence and confirmed the BMS accepted the pack without fault codes. The charge IC reached full termination voltage and the protection circuit held within spec under sustained diagnostic load.
- Post-installation self-test: After swapping the battery, let the mPack complete its full power-on self-test without interruption. The device runs a BMS verification sequence at startup — cutting power during this window triggers a false battery fault that persists until the next clean reboot cycle.
Why the mPack alarms low battery immediately after a confirmed full charge
The mPack's BMS stores a capacity baseline from the previous cell. When a new pack is installed, the charge IC has no learned profile to reference, so the device may read state-of-charge conservatively and trigger a low-battery alarm even at full voltage. This is a calibration gap, not a faulty cell. Run one complete charge-discharge cycle without interrupting the self-test sequence, and the BMS recalibrates its threshold to the new cell's actual capacity curve. After that first full cycle, the alarm behaviour normalises.
mPack not completing boot sequence after battery replacement
A cell that has sat in storage for several months may drop below the mPack's BMS recovery threshold through self-discharge — typically below 6.0V on a 7.4V nominal pack. At that voltage, the protection circuit blocks output to prevent damage, and the device stalls mid-boot or shows no response at all. Place the battery on charge immediately after unpacking and leave it connected until the charge indicator completes a full termination cycle before installing it. If the charger shows no activity on first connection, confirm input voltage at the charger output — the cell may need up to 15 minutes at trickle current before the BMS unlocks and accepts a standard charge rate.