Motorola GP350 Replacement Battery HNN9360 7.5V 2500mAh

Motorola GP350 — 7.5V Ni-MH Replacement Battery (HNN9360)

This is a 7.5V, 2500mAh Ni-MH battery for the Motorola GP350 portable UHF two-way radio. It replaces OEM part numbers HNN9360, HNN9360A, HNN9360B, and HNN9360C. The GP350 is used across security, public safety, and commercial field operations — this battery restores full transmit power to units running on aged or depleted packs.

• GP350 platform fit: The GP350 draws transmit current in sharp spikes each time PTT is pressed. The HNN9360 cell stack is rated to handle that surge without triggering BMS overcurrent cutoff — unlike generic Ni-MH packs that use lower-rated cells at this voltage rail.
• Bench tested on actual hardware: We cycled this pack through repeated PTT bursts at full UHF transmit load. The BMS held without cutoff across the full discharge curve, and terminal voltage stayed within the GP350's accepted operating window.
• First insertion into the charger dock: If the dock shows a fault LED on first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The GP350 charger 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 Ni-MH pack

A fresh Ni-MH cell ships at storage voltage — typically 1.0–1.1V per cell, which puts a 6-cell 7.5V pack around 6.2–6.6V at rest. The GP350's BMS monitors terminal voltage under transmit load, and if the pack hasn't been through at least one full charge cycle, voltage sag during PTT can push the reading below the radio's low-voltage cutoff threshold. The radio interprets this as a depleted pack and shuts down the transmitter. Run a full charge cycle before first field use — the pack must reach its charged state of approximately 8.4–8.6V before the GP350 will sustain full RF output.

GP350 bar indicator showing one fewer bar than expected after swap

The GP350 uses a simple voltage-threshold bar indicator — each bar corresponds to a voltage band, not a percentage calculated by a chip. A new pack at storage voltage reads one or two bars even though the cells are not depleted. This is normal behaviour and not a cell fault. Charge the pack fully before reading the indicator — once terminal voltage reaches 8.4V or above under no-load conditions, the bar display will reflect the actual state of charge correctly.