I am working on installing a hidden usb power adapter. My son who has been driving my 2005 Prius doesn't like the cord dangling from my Garmin gps I have suctioned to the windshield to the right of the rear view mirror. So I have this idea to put the usb power adapter in the sunglasses storage compartment and run the power wire out to the gps from there. I already have the usb adapter modified with a red and black wire coming out of it for the 12 volt hook up to the dome light wires. I want to have it powered on all the time unlike the 12v power outlets in the car that shut off when the car is turned off. (I hate that) Anyway, has anyone done this before? Any gotchas to be aware of?