About this replacement
MODECOM MX3 HD — 3.7V Li-Polymer Replacement Battery (1ICP4/44/54-3PIN60)
This 3.7V 1300mAh Li-Polymer cell is a direct replacement for the MODECOM MX3 HD portable GPS navigator. It restores power to the unit when the original battery has degraded or failed. Capacity is 1300mAh (4.81Wh) — taken from product data, not estimated.
- MX3 HD fit: The MX3 HD uses a compact Li-Polymer pouch cell with a 3-pin connector that carries a thermistor line alongside the positive and negative leads. The BMS reads cell temperature through that third pin — a standard 2-pin cell will not satisfy the handshake and the unit will refuse to charge.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on GPS-class draw. The protection circuit tripped correctly at low-voltage cutoff and the unit resumed normal operation after a full recharge without any error flags.
- Cold-start sequence after fitting: After installing this cell, power the MX3 HD on outdoors and leave it running in open sky. Removing the battery triggers a full cold start — the GPS receiver has lost its ephemeris data and needs 5–10 minutes to reacquire satellite almanac before the first fix. Subsequent power cycles return to warm-start lock in under a minute.
MX3 HD shutting off without low-battery warning
The MX3 HD's fuel gauge is calibrated against the original cell's discharge curve. A new or degraded cell with a slightly different voltage profile causes the unit to hit the BMS cutoff threshold before the on-screen battery indicator reaches empty. The device goes dark with no visual warning because the indicator and the actual cell voltage are out of sync. Run two or three full charge-discharge cycles to let the gauge recalibrate — after that, the warning icon should appear several minutes before shutdown at approximately 3.4V.
Saved routes and POIs missing after battery swap
Some navigation data on the MX3 HD — including recent destinations and certain POI favourites — is held in battery-backed volatile RAM, not written to flash storage. A complete power removal wipes that segment of memory. Data stored to the internal flash or SD card survives the swap intact. Before pulling the old cell, export saved routes through the device's backup menu to preserve them.