Join Date: Jul 2005
Location: Dutchess County, NY
Bikes: Fuji S-12s, Trek Navigator 200, Dahon Vitesse D7, Raleigh Sprite Touring ('70's)
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I have been looking for a better light than my old Specialized Astro 5 (which dropped dead on me recently) for occasional, recreational night riding. I looked into building my own using various MR16 halogens, then started looking into LED.
After looking at some Luxeon datasheets I purchased a flashlight that used the Luxeon III emitter mounted on the star heatsink. They claim 70-80 lumens, and I believe it. I'm throwing away all of my AA, C & D cell halogen (krypton and xenon) flashlights, and replacing them with these little wonders. I sent my daughter to Girl Scout camp with one and two extra sets of batteries (3 AAA cells). Remarkably, she came home with the original set still in use. She claimed to have used it for an hour or two each night, and her light was the talk of the camp.
I am thinking of modifying two heads for bike use (near - wide spread, far - narrow beam), and driving both with one external battery pack. 6 watts of power, 150 lumens out in two patterns. The reason I bring this all up is that the claims made by NiteHawk sound a bit overly optimistic.
The K2 emitter is a step up, but not that much. At max rated current (1500ma - about 5 watts input), it is good for 140 lumens or so. That is terrific (around 30 lumens per watt), but in no way would it compare with a 20 watt halogen. I would think you should be able to get around 350 lumens out of a 20 watt halogen. Plus, the beam pattern they show in their product sheet looks pretty narrow - almost pencil beam. Wonder how well it would really work as a bike light.