All you need is ANY usb power device, then connect it to your aux you can hide it all in your glove box.
http://www.ebay.com/itm/New-USB-Wire...item2a4ff53e43
I use these on my custom radios
www.rockboxaudio.com
And i use it in my car, auto connects when you turn the power on, super clear, works great! And its under 6$.