About this replacement
Xact Communication Wristlinx x3x Series — 3.7V Li-ion Replacement Battery (XB10)
This is a 3.7V, 550mAh Li-ion replacement for the XB10 battery pack. It fits the Wristlinx x3x wrist-mounted two-way radio and powers both the transmitter and receiver circuits. The same pack also fits the Wristlinx x2x, x33xif-2, and x33xif variants.
- Wristlinx x-series compatibility: These models share the same 3.7V single-cell architecture, XB10 connector pinout, and BMS handshake protocol — one pack covers the full lineup.
- Bench tested on actual hardware: We ran the XB10 pack through full charge and discharge cycles on the Wristlinx platform. The BMS handled PTT transmit spikes without tripping into overcurrent lockout, and the protection circuit responded correctly at low-voltage cutoff.
- First insertion on the Wristlinx dock: If the charger shows a fault indication on first insertion, remove the pack, wipe the contact pads with a dry cloth, and reseat firmly. The Wristlinx dock requires a clean contact cycle to complete the BMS handshake before it begins charging.
Why the Wristlinx x3x cuts out mid-transmission on a new XB10
A new XB10 ships at storage voltage — typically around 3.6V — not a full 4.2V charge. When PTT is pressed, the transmitter draws a sharp current spike that briefly drops cell voltage below the BMS cutoff threshold. The radio interprets that voltage sag as a depleted pack and kills the transmit circuit. Charge the pack fully before the first use to bring the cell above 4.1V and eliminate this behaviour.
Bar indicator showing one fewer bar than expected after inserting a new XB10
The Wristlinx uses a simple voltage-threshold bar indicator — each bar maps to a specific cell voltage band. A new pack at storage voltage sits in the second or third bar band, not the top. This is not a capacity fault; the cell is healthy but not fully charged. Put the pack on the dock until the charge indicator clears, and the bar display will read the correct level at or above 4.1V.