About this replacement
Beamex MC2-TE / MC2-PE Series — 3.6V Ni-MH Replacement Battery (MC28B)
This is a 3.6V 3600mAh Ni-MH battery pack for the Beamex MC2 series portable calibrators. It fits the MC2-TE, MC2-PE, MC2-MF, and MC2-IS models, replacing OEM part numbers MC28B, 8036140, and MC2BP. The MC2 series are field-use temperature and process calibrators, and this pack slots directly into the battery compartment at the rear of the unit.
- MC2 series compatibility: All MC2 variants listed share the same 3.6V single-cell Ni-MH battery bay, connector pinout, and BMS handshake. Swapping between MC2-TE, MC2-PE, MC2-MF, and MC2-IS units is straightforward — the pack draws from the same voltage rail and communicates charge state identically across all four models.
- Bench tested on actual hardware: We cycled this pack through the MC2 charge circuit and monitored BMS behaviour under simulated sensor load. The protection circuit held steady through probe initialisation current spikes without tripping, and charge termination occurred cleanly at full capacity.
- Post-install calibration cycle: After fitting this pack, run a full calibration cycle through the MC2 instrument menu before taking it into the field. The MC2 maps battery state during that process — skip it and the low-battery indicator fires prematurely on your first measurement session, even with a full charge.
BMS lockout after the MC2 sat unused in a carry case for months
Ni-MH cells self-discharge over time, and a pack stored inside a closed carry case can drop below the BMS recovery threshold — typically around 2.8V on a 3.6V Ni-MH cell — within three to six months. When the MC2 charger detects a voltage this low, it may refuse to begin a charge cycle, leaving the display dark and giving no fault indication. To recover the pack, use a Ni-MH-capable charger with a trickle or recovery mode that applies a low current — around 50–100mA — until the cell climbs back above 3.0V. Once it crosses that threshold, normal fast-charge resumes.
MC2 readings drifting or logging session resetting mid-run
During a sustained logging session, the MC2 draws continuous current to power both the display and the active sensor input simultaneously. On a degraded or partially charged Ni-MH pack, this combined load causes a voltage sag that briefly drops the supply below the processor's minimum operating voltage. The MC2 interprets this as a power fault and resets the active session rather than shutting down cleanly. Charge the pack fully before any logging job, and confirm resting voltage reads above 3.4V before you start — that's the practical floor for stable sustained operation on this platform.