Magellan RoadMate 1440 M1100 Replacement Battery 3.7V

Magellan RoadMate 1440 — 3.7V Li-ion Replacement Battery (M1100)

This 3.7V 1100mAh Li-ion cell replaces the OEM M1100 battery in the Magellan RoadMate 1440 portable GPS navigator. It fits the dashboard-mounted unit used for vehicle turn-by-turn routing. Voltage and capacity match the original spec exactly — 3.7V, 1100mAh (4.07Wh).

• RoadMate 1440 fit: The M1100 cell uses a fixed connector and BMS profile matched to the RoadMate 1440 power rail. The device communicates with the BMS to confirm cell identity before enabling charge. An incorrect cell voltage will fail that handshake and the unit will not charge.
• Bench tested on actual hardware: We ran the M1100 through full charge and discharge cycles on the RoadMate 1440 board. The BMS handshake cleared on the first connection, charge acceptance was normal, and the protection circuit responded correctly to discharge floor conditions.
• Cold-start satellite acquisition: After fitting this cell, power the unit on outdoors before driving. The GPS performs a cold start after any full power interruption and needs an open sky view to re-acquire satellite lock — allow up to 10 minutes for first fix before relying on routing.

GPS accuracy reduced at low battery on the RoadMate 1440

The RoadMate 1440 receiver draws more power during active satellite tracking than during standby. When cell voltage drops below roughly 3.5V, the unit reduces receiver sensitivity to protect remaining charge. That reduction affects position accuracy — the GPS may show a coarser location fix or lose lock briefly in areas with weak signal. Keeping the cell above that threshold during active navigation prevents the sensitivity drop.

RoadMate 1440 shuts off without low-battery warning

The on-screen battery indicator on the RoadMate 1440 reads state of charge from a calibration map stored in firmware. After a full battery swap, that map is out of sync with the new cell's actual discharge curve. The unit hits the hardware voltage cutoff — around 3.0V — before the software indicator reaches the warning threshold. Run two full charge-to-discharge cycles to let the firmware recalibrate the indicator against the replacement cell's curve.