This project had been on my mind for some time seeing as all newer cars have some sort of USB power outlet. Not having one in my truck was always a pain especially with having to use specialized adapters to power or charge my phones. This became especially important on roadtrips where I have the GPS on the phone going along as a 4g access point feeding our iPad.
I tried many adapters that plugged into the cigar lighter (left side power point) but most did not put out enough amperage to charger my tablet. After doing some reading I found that the tablet required the maximum 2.1A that USB was able to provide and it explained why none of my cheap adapters were working.
The solution? Retrofit!
This project took all of an hour and looks nearly factory. And, as a non-smoker, losing the cigar lighter didnt really affect me. See the pics for the finished product.
I hope this helps someone in the future as it did me.
Bought from here for about $20
Dual USB Charger Socket - 2 USB Ports w/Watertight Cap
update : I measured the current across the usb socket and it appears to be about 27mA when its not doing anything and has the LED on. Just FYI for people who are interested. For my taste thats a bit high so I may tap into one of the delayed accessory circuits and add a relay. The blue sea site lists the parasitic draw as 15mA but is obviously higher.
note: this was done an on 08 F250 Lariat SCREW, upfitters, 6.4L Diesel. Happy to answer questions.