Icom IC-M25 Marine Radio Replacement Battery BP-282 3.7V

Icom IC-M25 — 3.7V Li-ion Replacement Battery (BP-282)

This is a 3.7V, 1400mAh Li-ion replacement battery for the Icom IC-M25 compact marine handheld VHF radio. It replaces OEM part number BP-282 and fits directly into the IC-M25 battery compartment. Voltage and contact layout match the original so the radio's BMS handshake completes on first insertion.

• IC-M25 fit confirmation: The IC-M25 runs a single-cell 3.7V Li-ion pack at a slim profile — 52.50 x 38.00 x 6.70mm. That form factor is specific to this marine handheld. The BP-282 footprint is not shared with Icom's land-mobile lineup, so there is no cross-fit confusion here.
• Bench tested on actual hardware: We ran this pack through the IC-M25 charge dock and confirmed the BMS handshake cleared without a fault LED. Transmit current spikes on PTT did not trip the overcurrent cutoff at any standard marine VHF power setting.
• First insertion into the charge dock: If the dock LED shows a fault on first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The IC-M25 dock requires a clean contact cycle before it accepts a new pack's BMS handshake and begins charging.

IC-M25 bar indicator showing fewer bars than expected on a new BP-282

New Li-ion cells ship at storage voltage — typically around 3.6V — not at a full 4.2V charge. The IC-M25 reads voltage thresholds and converts them to bar segments, so a pack fresh out of the packaging will display one or two bars rather than full. This is not a defect. Run the pack through a full charge cycle in the dock before judging capacity. After a complete charge, the indicator should hold at maximum bars at rest.

IC-M25 cuts out or drops TX power mid-transmission on the new pack

Marine VHF transmit draws a short, sharp current spike each time PTT is pressed. If the cell is not fully charged or if the gold contacts have oxidation or debris, voltage sags far enough under that load for the BMS to trip the overcurrent cutoff and kill the output. The radio goes quiet mid-transmission or switches to reduced power. Charge the pack fully first — resting voltage should reach 4.15V or above — then clean the contacts on both the battery and dock before the next use.