About this replacement
Icom IC-F3400 Series — 7.4V Li-ion Replacement Battery (BP-283 / BP-284 / BP-303)
This is a 7.4V, 3500mAh Li-ion battery pack for the Icom IC-F3400 series land mobile radios. It replaces OEM part numbers BP-283, BP-284, and BP-303. The pack fits the IC-F3400, IC-F3400D, IC-F3400DP, IC-F3400DPS, and over 18 additional IC-F3400 variants.
- IC-F3400 series platform fit: All IC-F3400 variants share the same 7.4V voltage rail, contact layout, and BMS handshake protocol. Swapping between D, DP, and DPS sub-models does not change the battery requirement — the same pack covers the full series.
- Bench tested on actual hardware: We ran this pack through charge and transmit cycles on the IC-F3400D dock. The BMS accepted the charger handshake cleanly, held voltage above 7.0V through sustained PTT bursts, and tripped overcurrent protection correctly at the expected threshold.
- First insertion contact check: 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 IC-F3400 charger dock requires a clean contact cycle to complete the BMS handshake before it will begin charging.
IC-F3400 cuts out mid-transmission on a new BP-283 pack
A new Li-ion cell ships at storage voltage — typically 3.6–3.7V per cell, giving around 7.2–7.4V at pack level. The IC-F3400 draws a sharp current spike at PTT press for RF output, and if the BMS reads voltage dipping below its trip threshold on that spike, it cuts TX power to protect the cells. This is not a faulty pack — it is the BMS responding to high impedance in an unconditioned cell. Run one full charge cycle through the dock before field use; cell impedance drops after the first full charge and the cutout stops.
Bar indicator showing one fewer bar than expected after fitting new pack
The IC-F3400 uses voltage-threshold bar indicators, not a fuel gauge chip. At storage voltage, the pack sits below the threshold the radio maps to a full-bar reading, so the display shows one bar short even on a brand-new cell. This is a voltage reading, not a capacity fault. Charge the pack fully in the dock until the charge LED goes green, then reseat it — the indicator will read correctly once the pack is at or above 8.2V resting voltage.