Oh, there's no lens in these flashlights, just a reflector (or is that what you meant?)

Anyway, I finished the wiring today, and I'm currently looking for some P-clamps to mount the flashlights to the handlebars. I have some pics, and I'll post them when I figure out how. But first, some observations...

These flashlights were those generic MXDL "Luxeon" flashlights you can find on eBay. I should note that these do NOT use genuine Luxeon emitters, rather they appear to be Chinese knockoffs. Still, they are really bright!

I bought a set of three, and they are all different colours. One has a blue tinge, another pink, and the third is a yellow-white. The last one is the brightest.

About heat: These things get hot! I am running them from a 9V source with a 1.5 ohm resistor, so that each one will get 4V at 700 mA (actually, 660mA). After less than 10 minutes they became uncomfortably hot. They are designed to operate with three AAA batteries which will theoretically force 4.5V into each emitter, though I doubt you'll get 700 mA out of a AAA battery! Luxeon's datasheets go into great detail about heatsinking, and as far as I can see, they need quite a bit. The knockoffs are no different, and I am considering using metal P-clamps and a metal base to screw them onto, for a little more heatsinking. Alternatively, I may replace the 1.5 ohm resistor with a 1.8, so that they don't draw so much current. It's a good thing that the flashlight bodies are aluminum, or they'd have burnt out already...

One other thing, the battery did not heat up at all during this time, so that's good. At least it can handle this current drain!