Fluke Memobox 6V Ni-MH Replacement Battery 5x2-3A600

Fluke Memobox — 6V Ni-MH Replacement Battery (5x2-3A600)

This is a 6V 1100mAh Ni-MH battery pack for the Fluke Memobox portable data logging and survey instrument. It replaces OEM part 5x2-3A600 and fits both the Memobox and Analyzers Memobox configurations. Capacity is 1100mAh (6.6Wh), matching the original specification.

• Memobox and Analyzers Memobox compatibility: Both units share the same 6V bus, physical form factor, and BMS handshake protocol — this pack covers either variant without modification.
• Bench tested on actual hardware: We cycled this pack through the Memobox charge and discharge sequence, confirmed BMS communication at start-up, and verified the cell voltage held within spec across sustained sensor logging load.
• First-use calibration cycle: After installing, run a full calibration cycle through the instrument menu before taking it into the field. The Memobox maps battery state during calibration — skipping this step causes premature low-battery warnings during your first measurement session.

BMS lockout after the Memobox sat unused in a carry case for months

Ni-MH cells self-discharge over time, and if the pack drops below roughly 4.8V total, the BMS enters a protection state and refuses to accept a standard charge cycle. The Memobox charger interprets this as a faulty pack and stops the charge sequence before the cells recover. To break the lockout, apply a slow pre-charge at low current — most multi-chemistry chargers have a conditioning or recovery mode that handles this. Once the pack climbs back above 5.4V, the BMS clears the lockout and normal charging resumes.

Memobox shuts down mid-logging session with no low-battery warning

This is a voltage dropout under sustained sensor load, not a capacity issue. When the instrument drives multiple probe channels simultaneously, the combined current draw pulls cell voltage down sharply — enough to trip the BMS undervoltage threshold before the display has time to flag a warning. The instrument cuts power to protect the cells. Charge the pack fully, then reduce simultaneous probe channels if the shutdown repeats. A healthy pack should hold above 5.4V under normal logging load; if it collapses below that under light load, the cells need replacement.