There is a piece you can buy that you can plug your radar detector plug into it and all you have to do is wire the hot & grnd to any power source. Those plugs have different resistance settings thats why they fit in the cigarette lighter and they get converted through the plug. We used to just open them up and find the power and ground connection and solder two new wires and run them to a power source in the truck. Either way you have options. I will try to find that piece and re post it for you.
Hope that helps. The solder thing is real easy though.
try this site
Radar Detector Power Cords