About this replacement
Maxon SP300 / SP310 / SP320 / SP330 Series — 7.2V Ni-MH Replacement Battery (WWH-ACC200)
This 7.2V, 2500mAh Ni-MH battery replaces the WWH-ACC200 pack in Maxon SP300, SP310, SP320, and SP330 portable two-way radios. It fits the same housing footprint and uses the same contact layout as the original. Voltage and capacity match the factory spec exactly.
- SP300 series compatibility: The SP300, SP310, SP320, and SP330 all share the same battery bay dimensions, contact pin arrangement, and 7.2V power rail. One pack fits every model in the series without modification.
- Bench tested on actual hardware: We cycled this pack under simulated PTT load on the SP310. The BMS handled the transmit current spike without tripping, and the charger dock accepted the handshake after a normal contact-seat cycle.
- First insertion into the dock: If the charger shows a fault LED on first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The SP300 series dock requires a clean contact surface to complete the BMS handshake before it will begin charging.
Why the SP300 cuts out mid-transmission on a new WWH-ACC200
A new Ni-MH cell ships at storage voltage — typically 1.0–1.1V per cell, which puts a six-cell 7.2V pack somewhere around 6.3V at rest. When PTT is pressed, the transmit current draw causes a voltage sag that can pull the pack below the radio's low-voltage cutoff threshold before the cells have been properly conditioned. The radio interprets this as a depleted pack and drops the transmission. Running one or two full charge-discharge cycles brings the cells to working capacity and raises the resting voltage enough to handle the TX current spike cleanly.
Bar indicator showing one fewer bar than expected after fitting this pack
The SP300 series reads battery level using voltage thresholds, not a fuel gauge chip. A new Ni-MH pack at storage voltage will read one bar low even when fully seated and undamaged. This is not a fault with the cell — it reflects the actual resting voltage of an unconditioned pack. Charge the battery fully in the dock until the LED goes green, then check the bar indicator again. After a full charge cycle, the indicator should read at the expected level.