have a garmin c60 or 68, and has the optional 12v pwr cord which I have used this way on the boat for 2-3 yrs, now I use it in my yak on just 2 AA batteries, have used it this way on one set of batteries for 4 or 5 months, and the battery meter on it says the batteries have about half a charge remaining. I use it for 3-5 hrs a time, once a week, been pleased with it so far. Screen is small but in the yak I lay it on the floor/deck and can see it fine for my purpose of marking waypoints. Been considering putting a gps/ff on the yak to reduce the clutter around the feet.
GO BIG ORANGE !
I meant to behave, but there were just way too many other options available at the time.