ThoughtTech MyoTrac MI1027 Compatible Battery 4.8V 700mAh

ThoughtTech MyoTrac Infiniti Series — 4.8V Ni-MH Replacement Battery (MI1027)

This is a 4.8V, 700mAh Ni-MH replacement battery for the ThoughtTech MyoTrac, Myotrac Infiniti, Myotrac Infiniti U-Control, and U-Control Infiniti encoders. It matches the OEM part number MI1027 and fits the original battery compartment without modification. Voltage and capacity match the factory specification exactly.

• MyoTrac and Infiniti platform compatibility: These models share the same 4.8V four-cell Ni-MH power rail, identical connector pinout, and the same BMS handshake protocol — which is why one battery covers the full range. Voltage tolerance across the platform is tight, and a cell that drifts outside spec will trigger a low-battery fault even at partial charge.
• Bench tested on actual hardware: We cycled this cell through the MyoTrac's startup sequence and monitored the BMS verification pass. The protection circuit held cutoff at the correct low-voltage threshold and the charge IC accepted a full charge cycle without triggering a fault flag.
• Post-swap startup protocol: After installing this battery, let the device complete its full power-on self-test without interrupting it. The MyoTrac runs a BMS verification at boot — cutting power during this sequence causes a persistent false battery fault that won't clear until the next complete reboot.

Why the MyoTrac alarms low battery with a freshly charged replacement installed

The MyoTrac's charge IC calibrates its low-battery threshold against the OEM cell's charge curve. A new Ni-MH cell hasn't established that curve yet, so the BMS reads its resting voltage conservatively on the first cycle. The device may alarm even when the cell is at or near full capacity. Run one complete charge-discharge cycle before clinical use — after that single cycle, the BMS reads the cell accurately and the false alarm stops.

Device won't power on after the replacement battery sat in storage

Ni-MH cells self-discharge during storage. If voltage drops below the MyoTrac's BMS recovery threshold — typically around 4.0V for a 4.8V pack — the device won't respond to the power button at all. The BMS enters a protective lock-out state that a standard charger won't break. Place the battery on a Ni-MH charger with a recovery or trickle mode first, bring the pack back above 4.4V, then reinstall and attempt a normal power-on.