vr, these are commercial LED trailer marker lights. They are designed to plug right into a 12V source. For waterproofing short term, just put the battery in a water resistant bag of some kind, freezer baggy, FEDEX tyvek envelope (very tough). Just put battery and connectors down in the bag then fold the top part down alongside the battery. You don't have to seal it. Water only runs down. If possible position exposed wires so that they are coming UP under cover into the outer bag and a leave a little loop of wire down ( think U shape) instead of going straight down into the bag. This will keep water from runniing down the wire into your bag and connections.

Pete, I tell you what, buddy, this 35W high color temp Solux MR-16 lamp is very close to the HID I had. They only cost about $6. I just received the Phillips MR-16 lamp that is supposed to provide 35W equivalent light with only 20W draw. I am getting about 1:20 of good light with the 35W bulb on my 5AH battery.

Here is a side by side shot of the 35W Solux 10 degree spot, left, and the 20W Phillips 8 degree spot beams on a wall at close distance. It is difficult to draw conclusions about the relative brightness at such close distance, but you can definitely see the difference in color temperature, the Solux is 4700K and the Phillips 3100K. Now you can see what I have been talking about with regard to color temperature and "whiteness".