About this replacement
Midland G-28 / G-30 — 7.2V Ni-MH Replacement Battery (20-555)
This is a 7.2V, 700mAh Ni-MH replacement battery for the Midland G-28 and G-30 handheld two-way radios. It uses OEM part number 20-555 and fits directly into the battery compartment on both models. Voltage and capacity match the original Midland specification.
- G-28 and G-30 compatibility: Both radios share the same battery bay dimensions, contact arrangement, and 7.2V supply rail. One battery fits both units without adapters or modifications.
- Bench tested on actual hardware: We ran this pack through charge and discharge cycles on the G-28 platform. The BMS held stable voltage under PTT transmit current spikes without tripping into protection mode.
- First insertion after storage: Ni-MH cells ship at partial charge. If the radio powers on but shows only one bar, place it on charge immediately — do not key up and transmit at full power until the first charge cycle completes. Transmitting at low cell voltage accelerates early capacity fade in Ni-MH chemistry.
Why the G-28 cuts out mid-transmission on a freshly inserted battery
Ni-MH cells at storage voltage sit around 1.1–1.2V per cell. Under PTT transmit load, that voltage sags sharply. The G-28's low-voltage cutoff circuit reads that sag as a depleted pack and drops the RF output or shuts transmission entirely. This is not a faulty battery — it is the protection circuit doing its job on an uncharged cell. Charge the pack fully before the first transmission and the cutout behaviour stops.
Bar indicator stuck on one bar after a full overnight charge
The G-28 uses a simple voltage-threshold bar indicator — it reads resting cell voltage and maps that to bars on the display. A new Ni-MH pack that has never been cycled can show a suppressed resting voltage even after a full charge, because the cells need one or two complete charge-discharge cycles to reach their rated capacity. Remove the battery, leave it out for two minutes, and reinsert it. If the indicator still reads low after a second full charge cycle, check that the contact strip on the battery is clean and making firm contact with the radio's terminal plate.