vrkelley, watts = amps x volts, so amps=watts/volts or in this case 20/12=1.67 amps. Is that right electronics whizzes?

vixen, I think I have all my components assembled, EXCEPT, the lights themselves, which must be on the slow UPS truck! Once I get them I will start cobbling together my system. I still have to work out mounting and switches. Initially I will just kind of clamp things on the best I can as I refine the electrical setup, but eventually I would like to figure out a mounting system that is not too difficult to move from one bike to another. And how about some brake lights...and turn signals. The opportunities for geekiness are without limit! I will post some pictures as I have something to show, particularly comparing the light beams of some of the interesting bulbs I have found.

To those of you who have recommended various reasonably priced bike lights your suggestions are appreciated but miss the point of the exercise. First and foremost to me is the fun and challenge of assembling a nice light setup from easily available, inexpensive components that provides a lot of light for the cost. I, personally, want a 12V system rather than a 6V sytem because it will drive more powerful lights at half the amps and there is a plethora of small 12V SLA batteries from which to choose, depending on how much light one wants and for how long. So I guess one person's hassle is another's interesting challenge. The ride is more important than the destination.