I run two headlights. Both are small Union housings with screw base halogens. I put one 6V 6W halogen in the right side and a 6V Super Bright LED cluster in the other. This was supposed to help on battery run time.

The LED did ok on my way to work. On my way home I had a melt down. I took the LED out and it was a ball of burnt plastic. It got too hot in the housing.

I went back to 6V 3W and 6V 6W. I'll keep watching this post to see what you guys come up with. BTW, I did find out one interesting thing. LEDs like to be powered one way. I had to re-wire one side of my lights. LEDs like to be powered from the bottom and ground through the side.