Mares ICON HD Replacement Battery 3.7V 2600mAh

MARES ICON HD / ICON Genius Series — 3.7V Li-ion Replacement Battery (44201389)

This 3.7V, 2600mAh Li-ion cell replaces the original battery in the MARES ICON HD, ICON Genius, and Genius Air dive computers. These wrist-mounted units handle depth tracking, decompression calculations, and GPS surface navigation — all of which stop working when the cell dies. Voltage and capacity match the OEM spec exactly.

• ICON HD, ICON Genius, and Genius Air compatibility: All three models share the same battery bay dimensions, connector pinout, and BMS handshake. The 44201389 and 44200755 part numbers cross-reference to the same cell — same voltage rail, same pack geometry, same communication protocol with the dive computer's charging circuit.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the ICON HD platform. The BMS accepted full charge without error flags, and the device's battery indicator tracked correctly across the discharge curve from 4.2V down to the 3.0V cutoff threshold.
• Cold-start satellite acquisition after fitting: After any full power removal, the GPS module loses its ephemeris data and performs a cold start. Power the device on outdoors with a clear sky view and allow 5–10 minutes for the first satellite fix. Subsequent warm starts will lock in under a minute once ephemeris is cached again.

Why the ICON HD battery indicator gives little warning before shutdown

The ICON HD reads battery state by sampling cell voltage, not a gas-gauge IC. A fresh cell holds voltage well through most of its discharge, then drops steeply in the final 10–15% of capacity. This means the on-screen percentage can read 20% and drop to cutoff quickly, especially under GPS-active load. After fitting a new cell, run one full charge-discharge cycle so the device calibrates its voltage-to-percentage mapping accurately. Until that cycle completes, the low-battery warning threshold may trigger later than expected.

Saved dive logs and routes disappearing after battery swap

The ICON HD stores dive logs in onboard flash memory, which is non-volatile and survives a full power loss — logs should persist after a battery swap. GPS waypoints and surface routes, however, may be held in battery-backed SRAM on some firmware versions, and a complete power interruption can wipe them. Before removing the old cell, export any saved routes via the Mares dive management software. After fitting the new cell and completing the cold-start satellite fix, re-import your waypoints from the backup file.