About this replacement
Motorola GP350 — 7.5V Ni-MH Replacement Battery (HNN9360)
This is a 7.5V, 1800mAh Ni-MH battery for the Motorola GP350 two-way radio. It replaces OEM part numbers HNN9360, HNN9360A, HNN9360B, and HNN9360C. The GP350 is a land mobile radio used across dispatch, field operations, and emergency services.
- GP350 platform fit: The HNN9360 series covers the GP350 line because these radios share the same 7.5V Ni-MH voltage rail, contact pin layout, and BMS handshake protocol. All four OEM variants are electrically identical — suffix letters reflect regional or batch revisions, not spec changes.
- Bench tested on actual hardware: We cycled this pack through full charge and discharge on a GP350 body, monitoring BMS response during PTT transmit bursts. The overcurrent protection triggered correctly at spike threshold and reset without lockout.
- First insertion on 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 GP350 dock requires a clean contact cycle to complete the BMS handshake before it will begin charging.
Why the GP350 cuts out mid-transmission on a new HNN9360
New Ni-MH cells ship at storage voltage — typically 1.0–1.1V per cell — not full charge. When the GP350 fires the transmitter, it draws a short current spike that can push a low-voltage pack below the BMS cutoff threshold. The radio drops TX output or resets mid-call. This is not a faulty battery. Run one full charge cycle on the dock before the first operational shift and the pack will hold the transmit load correctly.
Bar indicator showing one fewer bar than expected after charging
The GP350 reads battery level using voltage thresholds, not a fuel gauge chip. A freshly charged Ni-MH pack sits near 8.4V open-circuit but drops quickly to its nominal working voltage once under load. If the radio shows one bar short immediately after charge, let the pack settle for 15 minutes off the dock before reinserting. If the bar count stays low after a second full charge cycle, check that the dock contacts read at least 8.0V at the pack terminals before seating the radio body.