Radio Shack sells an adapter that would work. It's rated at 10 amps and comes
with a pos and neg binding post, like that on a power supply. With a decent car
ACCESSORY port (not cigarette lighter port), you can run a 50 watt FM radio. I
have been using on in my work car with no problems. The radio indicated over
14VDC when it is turned on and plugged into the aftermarket accessory port.

At the aft end there two
nice big red/black screw-down terminal posts of the usual design which
can accomodate up to #10 wire, maybe even #8. Nicely finished, quality
piece

That sounds like the one I picked up from Radio Shack. Part number 270-1521.
Here's a link:

http://www.radioshack.com/product.as...%5Fid=270-1521

Hope that helps!
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
73! de Andy KC2SSB
Beachwood, NJ USA! Grid FM29vw
http://vhfradiobuff.tripod.com