I hooked my Samsung galaxy tab 2 (7") up to ship's power. Good readability at full brightness, and I haven't had a problem with it getting hot and losing GPS signal. I figure that it must not be putting much of a load on the battery (causing the battery heating?.) Just a guess.

The 7" form-factor is a little big in the glider when climbing in, but I figure that if I needed to get back out in a hurry that I won't even notice just pushing it aside w/ the Ram-mount attachment to the sidewall.
~7U