"Ron Lee" wrote

And my Etrex will run about 12 hours ona fresh set of rechargeable
batteries. My Airmap may not last that long but surely enough for a
typical cross-country flight. No cigarette lighter plugin is needed.

There is also the choice of taking one of those emergency car starting
battery units, too. For a couple pounds of luggage, you can run whatever
you want, for a long time, and not spend any money on batteries; just
recharge the car jumper back up.
--
Jim in NC