I've been using a 1/2" flat screen that I just lay over the top of the bullet after I've loaded it. It eliminates replacing the screen in the gpong or building a screen to put in the bullet.
For a car charger, go to http://www.harborfreight.com/ and buy a 80 Watt Continuous/160 Watt Peak Power Inverter for $17.99 and just plug your charger in.