vr, use a gallon size freezer baggie (heavier plastic). Fold the top over, down beside the battery so that the cables exit down. Remember, water only runs downhill. It can't trickle back UP to the battery. Regarding condensation. Anytime my (not waterproof) handlebar bag gets wet I take every thing out and prop it open to let it dry as much as possible. For now I am taking the battery out every day for charging so condensation is not an issue yet.

I made this first bracket from aluminum bar 1/16 inch thick, 1 1/2 inches wide. It is VERY simple. I will try to describe. Picture a lower case letter "b", or "d" for that matter depending on which side you view it from. The loop part is a rectangle about handlebar wide and roughly 3 inches long. The bar is bent to form this shape with the bottom of the loop (rear when horizontal, as used) bent at right angles, as well as the top upper corner. The upper part is two layers thick as the pieces come back together. This is to give a little thickness and stability for mounting the light. Now lay that letter "b" horizontal, loop down. Near the rear (bottom of the b), far enough from the rear for clearance of the switch is a 13/23" hole for the threaded part of the switch. Just back from the top of the loop is are 1/4" holes for a bolt to clamp the bracket to the bar. Another 1/4" hole on the doubled part will be to mount the light. I will post a picture in a day or two. So the switch, a push button "canopy" switch available from any hardware store or home center, is somewhat protected by the bracket. It will be further waterproofed with liquid tape and innertube. I am also going to see if one of the switch "bonnets" you may have seen at the marine store will thread onto this switch in place of the knurled nut that comes with the switch. Then I can encase the rear part of the bracket with a section of inner tube with a cutout for the switch, using the bonnet over that to keep water from flowing down into the switch. I tried just inner tube, but with inner tube tight enough, the spring in the switch isn't strong enough to pop back up. Looser inner tube defeats the purpose. If the bonnet doesn't have the same threading I will figure something else out and let you know. Again, my purpose is to do this with parts and materials that are easily available. I have parts from old light sets, weather resistant cables and switches, that would work great, but that wouldn't work for everyone, so what would be the point.

I am just trying to fill in one piece of the puzzle at a time. It is great fun, and already I have a VERY nice headlight!