Charging mobile devices in your car is nothing new, but since most of our phones are USB-based nowadays, using a bulky adaptor just seems unnecessary. Here's how to add a USB power outlet to your car.
A lot of modern cars have USB ports for playing music from iPods and other such devices, but cars that lack a Ford Sync-like system usually leave them behind. Over at DIY web site Instructables, however, user rosenberger31 found that his 2010 Prius had an open outlet under the dashboard panel, just begging to be used.
You'll need to know how to solder for this project, and you'll need one of the aforementioned bulky USB-to-car charger adaptors, but it actually shouldn't be that time consuming of a project. Plus, it'll actually create a second power outlet, so you can charge more than one device at a time. The hardest part of the whole process is probably going to be fashioning the cover for the USB port, and that's really if you want it to look pretty. Hit the link for the full instructions.
Add a USB Power Outlet in Your Car [Instructables]