[wagonman76]

I got my leds in the mail yesterday. I did a little digging on ebay and found the same thing cheaper. 500 leds for $30 including shipping. Enough for possibly 4 headlights plus a bunch to play with. 3.3v, 20ma, 18000 mcd, +/- 20 degree viewing angle.

Last night I did some messing around with them. I've got an old military power supply that my cousin gave me many years ago. You can use different combinations of terminals and get several voltages from 1v to 25v. One set of terminals gives me about 14.7v which I used. I've also got some leftover 330 ohm resistors from a TI85 serial cable I recently built.

I wired up the leds so they all faced very close to the same direction, sticking right off the power supply.

Initially I tried filing one flat on the end, and that pretty much killed the output. I tried polishing the flat surface back smooth, but that only helped a little. Looks like the best thing to do is leave them as-is.

First I used 2 sets of 4 leds each in series with a resistor. Only makes for 5ma current, of course they didn't even heat up. They were very bright. Then I removed one led each for 2 sets of 3, 15ma current. That made the total even a little brighter. I could feel a tiny bit of warmth above them on my palm after running them a few minutes, but the leds themselves didn't feel warm. Then for kicks, I pulled the resistor and they did get warm very fast, of course, and didn't even seem as bright (was probably killing them).

With the 2 sets of 3 (6 total at 15 ma), I could see it reflecting off a snowbank 100 feet away, and off the neighbors 911 sign about 180 feet away. The beam spread was pretty decent, and if you turn it a bit, there was a definite cutoff from the blinding zone that would come in handy.

I'll make a bigger array pretty soon and I'll leave some space behind them for possibly needed air circulation. Considering the 96 or so leds I figured earlier per light, so far it does look pretty promising for at least a driving light. Then I'll play with the headlights and see what happens. Even if it doesn't throw good enough for a high beam, it might make a pretty decent low beam.