12 Volt Xenon Puck Lights? Got a question

[Dean in Ct.]

Early on in my project I bought some Ace Hdwre xenon puck lights in a string of 3, designed to go under kitchen cabinetry. Everyone seems to think the will give off too much heat to use in the cabin so I am going to use them as galley lighting, out in the open air.
My question is this; Since the 110 line cord has a 12 volt converter (maybe transformer, I'm never sure) can I hook them up directly to my 12 volt system, eliminating the converter? Better yet can I put some sort of a switch between the converter and the fixtures so I can go either way, 110 AC or 12 volt DC?
I touched the terminals of 1 fixture to my battery and it lit up fine....
Little help?
Thanks!