Hi all. I have the Garmin 620 professional. The problem I have is that when it is plugged into the vehicle, the battery level still goes down until depleted, then it keeps shutting down and restarting. Thought it was faulty, so bought a new one. This new one also does it. It does not matter which vehicle I use it in or which cable I use. I'm starting to think it might be since the last update, as it has not always done this. Anyone experienced this and found a resolution?