I wanted some LED lights mounted on the bottom of the overhead cabinets above the bed/table in my 16'. These are primarily for reading lights.
I looked at lights available at some RV places. All I found were lights of the very high color temperature (4700K?). These are extremely bright and harsh and unpleasant (are you listening, RV dealers?). I wanted something a little mellower. So, I went to Home Depot and bought a three-light set of puck lights with a 120VAC plugin. They're about 3000K color, which is good. I knew the lights themselves were 12VDC, so I figured I'd just cut off the AC adapter and wire them up to my trailer wiring. Right? Easy. Good thing it was a set of three, and I only needed two. To test the concept, I took the first one out and wired it directly to my truck battery. Heh. One light down. That fried it.
Back to the books... Oh, they need to have limited current, do they? I spent a couple of hours learning about what turns out to be called an LED driver. I got one, nearly matching the specs on my puck lights, right here: http://www.ledsupply.com/led-drivers/buckpuck-dc-led-drivers.
The dimmer pot is probably not necessary. I got it cuz I was a little gun shy of blowing up another light unit, so I could set it low, then bring it to the desired brightness. I wired this into some existing wiring, and it works great. My wife and I love the result - very bright for reading, but not harshly white.
Moral: I don't always know what I think I know.