This is really a great thread. I sure wish I would have run into it a couple of weeks ago, before I started building my own light system. Would have saved some headaches, time and probably a little money too. You folks have done some amazing things with your lights.

Here's what I came up with after stumbling along on my own. The basic design came from one I found at Dan's Workshop ( http://www.dansworkshop.com ) but I deviated on a few things.

It's a dual-light system, two 12v, 20w Malibu lamps mounted in 1-1/2" PVC threaded connectors. The threaded connectors are screwed into PVC end caps, which each contain a toggle switch and wiring. I couldn't come up with an elegant way to mount the two completed PVC units together, so finally ran out of patience and just cut a piece of redwood to fit between them, then used zip ties to hold it all together. I may change that later, depending on how it performs. So far it seems good though.

I had an old, nearly-dead Specialized headlight (one of those little 4-AA ones), so stole its quick release and mounted that to the redwood center piece. There's rubber between the quick release and redwood, and also between the redwood and each PVC unit. I cut up an old automotive water hose for the rubber. Not sure how much that will help with shock, but it seemed like a good idea.

Lamp cord was used as wiring to the battery, which is a 4500mAH NiMH battery pack mounted inside a water bottle. There's also a fuse in the circuit, mounted near the battery. It's been a big problem trying to find a water bottle with a big enough opening to fit the battery pack inside, so I ended up just cutting the bottle in half and doing it that way. I'm not thrilled with it though, and may end up going to a seat bag instead, which seems much simpler.

It went out for its first test ride last night, and wow, is that baby bright! Unfortunately, there are a couple of bugs to be worked out.

First, after burning about 10 minutes, one of the lenses warped. After buying these lamps (from Home Despot) I was disappointed to find that they didn't have lenses, so I had to make some. I cut the bottoms out of a couple of clear water bottles and siliconed them to the PVC, but they turned out to be too wimpy and can't take the heat.

Then, after the lens warped, one of the lamps popped out. There are just three small screws holding each lamp in the PVC, and I think the heat made the PVC pliable enough to allow the edge of the lamp to get past one of the screw heads. Truth is, I was pushing against the unit trying to angle it down a little when the lamp popped out. My plan is to find some thicker plexiglass to use as lenses, and to make them big enough in diameter so they can be screwed to the PVC, thereby holding the lamps in too.

The battery pack and a smart charger came from batteryspace.com. I didn't want the extra weight of an SLA battery so decided that, for me, the extra expense for NiMH was worth it. The battery (10 C cells) is light enough to hold between my thumb and index finger without much effort (maybe a pound and a half?). It was about $31, the charger was $35. Those were my biggest expenses.

I can't say enough about batteryspace.com. I ordered on a Sunday evening, and they had it at my door by Tuesday. They also have a nice forum on their site which I found to be a really good resource for technical info.

I'm pretty much a know-nothing when it comes to electronics, but lately I do find it interesting, and this experience has taught me a lot more than I knew previously.