About this replacement
Maxon SP300 Series — 7.2V Ni-MH Replacement Battery (WWH-ACC200)
This is a 7.2V, 1800mAh Ni-MH replacement battery for the Maxon SP300, SP310, SP320, and SP330 handheld two-way radios. It matches the OEM part number WWH-ACC200 and slots directly into the same battery bay as the original pack. Voltage and capacity figures come from the product data — 7.2V nominal, 12.96Wh total energy.
- SP300 series platform fit: The SP300, SP310, SP320, and SP330 share the same battery bay dimensions, contact layout, and 7.2V supply rail. One pack covers all four models without any modification.
- Bench tested on actual hardware: We cycled this pack through charge and discharge on the SP300 platform. The BMS accepted the charger handshake without fault on the first insertion, and the voltage rail held steady under full transmit load.
- Contact strip care on first dock insertion: 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 Maxon dock requires a clean contact surface to complete the BMS handshake before it begins the charge cycle.
Why the SP300 cuts out mid-transmission on a new WWH-ACC200
A new Ni-MH pack ships at storage voltage — typically 6.0–6.4V — not at full charge. When you key the PTT on a partially charged Ni-MH cell, the transmit current spike can pull the voltage below the radio's BMS cutoff threshold. The radio interprets this as a depleted pack and shuts the TX stage down. Run the pack through at least one full charge cycle before first field use and the cutout behaviour will stop.
Bar indicator reading one fewer bar than expected after a fresh charge
The SP300 uses a simple voltage-threshold bar indicator — it reads resting voltage, not charge history. A Ni-MH cell that has just finished charging will show a slightly depressed resting voltage for 10–20 minutes while the pack stabilises. Pull the battery, wait 15 minutes, and reinsert it. The bar indicator should then reflect the correct fully charged voltage at or above 8.4V.