I have had good luck with lights from this manufacturer, and the prices are pretty good:http://tuffledlights.com/
I have their 27W floods mounted on my pontoon boat, two up front and one on the rear. I also have them on my Rhino UTV, one front and one rear. And then, I have four of them installed in my barn.
These are very bright, and do not attract bugs.
BTW, if you can connect your multimeter in series with your light and battery to measure current, see what your Amp draw is running. As was noted by TCK, it should be around 1.25 Amps for a 15W light.