In the raspberry pi portable console episode, Ben Heck tested his screen to determine what was the minimum voltage it could run off - 6V instead of 12V
Some of these 3.5" car displays actually run on 5V, but convert the 12V to 5V with a chip. http://www.raspberrypi.org/phpBB3/viewtopic.php?f=64&t=17651 shows how this chip can be removed and fed on 5V directly (such as USB or battery).
I thought it might be useful for anyone looking to make their own version of the raspberry pi portable console.
