About this replacement
Icom IC-F52D / IC-F62D / IC-M85 — 7.4V Li-ion Replacement Battery (BP-290 / BP-294)
This is a 7.4V, 1900mAh Li-ion battery for the Icom IC-F52D, IC-F62D, and IC-M85 two-way radios. It replaces OEM part numbers BP-290 and BP-294. The battery fits the same connector and BMS handshake profile across all three models.
- IC-F52D, IC-F62D, and IC-M85 platform: All three radios share the same 7.4V battery bay, contact arrangement, and BMS communication protocol. One pack covers all three models without modification or adapters.
- Bench tested on actual hardware: We cycled this pack through repeated PTT transmit bursts on the IC-F52D. The BMS held stable through sustained RF output and correctly applied overcurrent cutoff at the expected threshold — no false trips during normal keying.
- First insertion into 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 Icom dock requires a clean contact cycle to accept the BMS handshake from a new pack before charging begins.
IC-F52D bar indicator reading low on a freshly installed BP-290
New Li-ion cells ship at storage voltage — typically 3.6V to 3.7V per cell, which puts the pack around 7.2V to 7.4V at rest. The IC-F52D reads battery level using voltage thresholds, not a fuel gauge chip. At storage voltage, the radio may show one or two bars even on a brand-new pack. Run the pack through one full charge cycle in the dock first. After a full charge the resting voltage rises to approximately 8.3V–8.4V and the bar indicator reads correctly.
Radio drops to reduced TX power mid-shift on the IC-M85
The IC-M85 draws a sharp current spike — up to 2A or more — during transmit. On a cell with elevated internal impedance from age or deep discharge, this spike causes voltage to sag below the radio's power-management threshold. The radio responds by stepping down RF output to protect the circuit. This is not a firmware fault. If the pack recovers voltage within seconds of releasing PTT, the cell impedance is the cause — replace the pack and confirm charge voltage reaches 8.4V before the next shift.