Garmin Montana 600 Replacement Battery 3.7V 2200mAh

Garmin Montana 600 Series — 3.7V Li-ion Replacement Battery (361-00053-00)

This 3.7V 2200mAh Li-ion cell replaces the factory battery in the Garmin Montana 600, 600T, 650, and 650T handheld GPS navigators. It matches the original's voltage, capacity, and physical footprint. Swap it in when the existing cell no longer holds a charge or shuts the unit down prematurely.

• Montana 600 series fit: The 600, 600T, 650, and 650T all share the same battery bay dimensions, connector pin layout, and 3.7V supply rail. One cell covers the full range without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a Montana 650. The BMS accepted charge from the standard Garmin cradle immediately and held the cutoff voltage within spec throughout discharge.
• Cold-start satellite acquisition after swap: After fitting this cell, power the unit on outdoors and let it acquire a satellite fix before navigating. A full power interruption triggers a GPS cold start — first fix takes 5–10 minutes outdoors. Subsequent warm starts return to under a minute once the almanac data is cached again.

Why the Montana 600 shuts off without warning at low battery

The Montana 600 reads state of charge from the cell voltage curve. After a long period with a degraded battery, the fuel gauge calibration drifts. The unit may show two bars and then cut off seconds later because the actual cell voltage dropped past the 3.4V shutdown threshold faster than the gauge updated. Fitting a new cell resets the discharge curve the firmware tracks against, and the indicator becomes accurate again within a few charge cycles.

Saved routes and waypoints missing after battery replacement

The Montana 600 stores maps and most user data on internal flash, which is non-volatile and survives a full power removal. However, any unsaved active track logs or temporary route calculations held in RAM are lost the moment the battery is disconnected. Before pulling the old cell, go to Trip Computer and save the active track, then export any in-progress routes to the device's internal storage. Once the new battery is fitted and the unit boots, navigate to the Saved Tracks folder to confirm the data transferred correctly before heading out.