You need your phone on all the time, and while you're driving your car is no exception. That's why you need a cheap USB car charger. Most smart phones these days can be charged with a simple USB data cable. Just plug the cable into your USB car charger, and you can charge your phone while you drive. Tablet PCs that use a micro-USB charger can be charged in the same way. This is a great way to keep your device powered as you use the GPS function. A USB car charger will even allow you to charge your phone when your car isn't running.