Here is what you'll need to do to get the Apple TV into your car.
You'll need to provide 5V7.2A constant voltage to it.
After you've taken apart the Apple TV, just attach to Positive and Negative and it should work.
There is more then one wire to the Pos/neg terminals on the motherboard. Find the proper Positive terminal (brown wires) and negative wire and attach.
Important that you find a DC to DC converter that can maintain that voltage or it will not work
There have been a lot of chatter regarding putting your Apple TV in your car. With the growing number of entertainment system in Minivans, the apple TV would be the perfect choice. Not more having to bring DVD's, or music into your car. Just have iTunes automatically sync up your movies, TV shows, podcasts, and music while your car is parked in the driveway or garage!
The current problem with the Apple TV today is that it is powered by AC, with no good solution for the Car's DC power. Until now...
Here is our prototype for the DC-DC converter that will allow you to use the Apple TV in your car. The final version will be a simple swap out of the current power supply inside your Apple TV(we'll provide an How to Manual), and it will not have an external box as you see in our prototype here. We expect to ship soon pending the amount of interest this generates. We are taking pre-order price of $39.95 and can be placed here. (bottom of page)