GE DMS Go+ Replacement Battery 7.4V 3900mAh Li-ion

GE DMS Go+ / USM Series — 7.4V Li-ion Replacement Battery (GEIT1255323)

This is a 7.4V, 3900mAh Li-ion replacement battery for the GE DMS Go+ portable ultrasonic thickness gauge and the USM86, USM87, and USM88 flaw detector series. It slots directly into the battery compartment and communicates with the instrument's power management circuit. Capacity figure is taken from the product specification — 3900mAh (28.86Wh).

• DMS Go+ and USM86/87/88 compatibility: These instruments share the same 7.4V battery bay geometry, connector pinout, and BMS handshake protocol. The pack's protection circuit matches the charge termination thresholds the instrument firmware expects, so the battery gauge reads correctly across the full discharge curve.
• Bench tested on actual hardware: We cycled this pack through the DMS Go+ charge and discharge routine on the bench. The BMS handled the probe power-up current spike without tripping, and charge termination occurred cleanly at the expected voltage ceiling with no fault codes logged.
• First deployment calibration: After installing this pack, run a full calibration cycle through the instrument menu before heading into the field. The DMS Go+ maps battery state during calibration — skipping this step causes the low-battery warning to fire prematurely on the first measurement session, even with a full charge.

Why the DMS Go+ shuts down the moment a probe initialises

When the DMS Go+ powers up a transducer probe, there is a brief but sharp current draw as the pulser circuit charges and the probe module comes online. An aged or partially discharged cell cannot deliver that instantaneous current without the terminal voltage sagging below the BMS protection threshold. The BMS reads this as an undervoltage condition and cuts power to protect the cell — even if the battery indicator showed adequate charge a moment earlier. A fresh pack with full cell capacity handles this spike without voltage sag, and the instrument stays on through probe initialisation.

Pack shows charged but instrument will not turn on after sitting unused in a carry case

Li-ion cells self-discharge over time, and if the pack voltage drops below approximately 2.5V per cell during long storage, the BMS enters a deep-sleep lockout state and blocks both charging and output. The instrument sees nothing — it cannot wake the pack. To recover it, connect the battery to the GE charger and leave it for at least 30 minutes without interruption; most chargers apply a low-current pre-charge pulse that nudges the cells above the BMS wake-up threshold, typically around 3.0V per cell. If the charger LED does not change state within an hour, the cells have dropped too far for recovery and the pack needs replacing.