Yeah, I really don't think it is the gauge of the wires I used but I have a marine grade adaptor and some thicker gauge wire so I figure I will try it. I'll let you know. I've never had a radio this powerful so I wasn't sure. Midland sells the 15 watt unit with the cig adaptor hard wired on (which I have and works fine). The 40 watt unit comes with bare wires (and fuses) so I guess that's the clue...there is nothing in their manual that give much guidance though.
Thanks for the help.