The Kensington PowerBolt Duo is in our opinion the absolute best car charger for iPhones and iPads. It charges two devices simultaneously and is in stock now for $30.

Ever noticed that your iPhone charges faster from the Apple wall charger than from a USB port on your computer? That's because USB ports usually push 0.5 amps of current. The Apple wall charger is twice the power at 1.0 amp. No wonder it's faster. This is even more noticable with an iPad as the iPad wall charger handles 2.1 amps.

I've tried a number of car chargers in the past for my iPhone. They usually only output a small amount of current, causing the iPhone to charge very slowly. Especially when using GPS this has been a problem, arriving with a low battery. I've measured some chargers claiming to do 0.5 amp that in reality only put out 0.1 amps! This means that a cheap car charger may take 10 times longer to charge your iPhone than the Kensington PowerBolt. Allow more than twice as long again for an iPad.

The Kensington  PowerBolt is best thought of as an iPhone wall charger, and iPad wall charger, for your car. It has two ports. One outputs 1 amp, which is perfect for fast charging iPhone and iPod Touch. The second port can also be used for this, but will output 2.1 amps to quickly charge an iPad. Both ports work at once, so your iPhone can charge, and you can charge a second device like the an iPod touch - great for the kids. 

It also comes with a very high quality black USB to Dock Conncector charge lead, which looks so much nicer in the car than the white leads.

Highly reccomended.