Hi,

This is known issue with this unit which is particularly susceptible to any form of vibration which causes a loose contact with the batteries and causes it to power down.

First use a simple pencil eraser or piece of cloth to clean the contacts both on the batteries and inside the battery compartment itself.

Next to address the loose connection issue you can either

1) Place double-sided sticky tape in the battery compartment to keep the batteries in place and in good contact with the terminals.

2) Place a piece of foam on top of the cover before replacing it to help keep the batteries in place.

Place foam here before replacing cover.

These are pretty low tech solutions and ideally Garmin needs to address this issue properly. However, if your unit is out of warranty you may well find that this resolves the problem without any further cost to yourself.

Hope this helps. If so please do leave a vote for the solution.

Thanks.