About this replacement
Icom IC-703 / IC-703 Plus — 9.6V Ni-MH Replacement Battery (BP-228)
This is a 9.6V, 3000mAh Ni-MH replacement for the Icom BP-228 battery pack. It fits the IC-703 and IC-703 Plus portable HF transceivers. These radios draw sustained current during SSB transmission, so this pack matches the original voltage rail and connector exactly.
- IC-703 and IC-703 Plus compatibility: Both models share the same battery bay, connector pinout, and 9.6V supply requirement. The BMS handshake is identical across both variants, so one pack covers either unit without modification.
- Bench tested on actual hardware: We cycled this pack through full charge and discharge on an IC-703 chassis. The BMS held voltage within spec across the Ni-MH cell array and did not trigger overcurrent cutoff during simulated PTT events at full RF output.
- First insertion into the charger dock: If the dock shows a fault LED on first seating, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The IC-703 charging dock requires a clean contact cycle to complete the BMS handshake before charging begins.
IC-703 dropping to low TX power mid-QSO on a new BP-228 pack
The IC-703 monitors supply voltage and steps down RF output when the battery rail sags below threshold — typically around 8.5V under load. A new Ni-MH pack shipped at storage voltage sits near 9.0V open-circuit but can sag further during the first few transmit cycles before the cells stabilise. This is not a fault in the pack. Run two full charge-discharge cycles through the dock before field use and the voltage sag under PTT will reduce significantly.
Bar indicator showing one fewer bar than expected after fitting a new BP-228
The IC-703 reads battery level from a simple voltage-threshold indicator — it has no fuel gauge chip. A new Ni-MH cell delivered at storage voltage reads lower than a fully charged pack, so the radio displays one or two bars immediately after fitting. This is not a capacity problem. Charge the pack fully through the Icom dock until the charge LED goes green, then power on — the indicator should read at or near full at 9.6V.