The tablet computer needs a 20VDC power supply. I have a 12 to 20v power adapter, which lets me use this in the car.
However, my car no longer has a cigarette lighter plug, (sacrificed to make room for gauges) so I ran a new dedicated 12V positive wire from under the hood, through the firewall to the front for the computer. That power comes off a secondary fuse panel I added in the front of the car, which comes off the main can battery. (Aux 12V system.)
Don't worry Paul, I promise not to fry the Cougar this time.
(Just so everyone else knows. Serial cables carry power though them. Or er, at least a ground or something. Anyways, if you are doing something like this, be careful where your power comes from! 12v power source should be the same for the controller and computer. Do I have that right Paul?!)