Icom IC-M93D Marine Radio Replacement Battery BP-285 7.4V 1850mAh

Icom IC-M93D — 7.4V Li-ion Replacement Battery (BP-285)

The BP-285 is a 7.4V, 1850mAh lithium-ion battery for the Icom IC-M93D handheld VHF marine radio. It slots directly into the M93D battery bay and connects to the same BMS handshake points as the original pack. Voltage and capacity match the OEM specification — 7.4V nominal, 13.69Wh total.

• IC-M93D platform fit: The M93D runs a 7.4V two-cell Li-ion architecture with a proprietary connector and BMS communication line. The BP-285 form factor and contact arrangement match this layout, so the dock and radio firmware recognise the pack without reconfiguration.
• Bench tested on actual hardware: We cycled this pack through transmit loads replicating VHF PTT bursts and confirmed the BMS handled the current spike without tripping into overcurrent lockout. Cell voltage held above the low-battery threshold through repeated keying sequences.
• First dock insertion on a marine charger: If the charger LED shows a fault on first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The M93D dock requires a clean contact cycle to accept the BMS handshake before it starts the charge cycle.

IC-M93D bar indicator showing one fewer bar than expected on a new BP-285

New lithium-ion cells ship at storage voltage — typically around 3.7V per cell, not the 4.2V full-charge ceiling. The M93D reads pack voltage against fixed thresholds to light each bar segment. At storage voltage the radio correctly shows two or three bars rather than full. Charge the pack completely in the dock before drawing any conclusions about capacity. After a full charge cycle both cells should sit at 4.2V and the indicator will reflect actual charge state.

IC-M93D cuts out mid-transmission on a freshly inserted BP-285

PTT on a VHF handheld draws a sharp current spike — the M93D transmitter pulls significantly more current the moment you key up than it does on standby. If the BMS sees this spike before it has completed its initialisation sequence after insertion, it can trip overcurrent protection and kill the output mid-call. Remove the battery, wait ten seconds, reinsert, and let the radio sit powered on for thirty seconds before transmitting. If the cutout repeats, check that cell voltage is above 3.6V per cell before keying.