About a year ago, I started to build a LED headlight to run off my Schmidt generator hub. I have been running two Busch and Muller Lumotec halogen headlights wired in series. Most of the time I only have one turned on. For backup, I have a battery-powered Cateye HL-EL500. I primarily use the Cateye in town when I have to stop frequently because the Lumotecs do not have a stand light and require a little speed to begin to illuminate. I also have a small white LED button light affixed to the front of the trunk that I run at night to make me more visible from the front when I am stopped. I have a Princeton helmet light that I wear at night as well, but I usually only have it on to read the que sheet or street signs.
The design I started with was based on the Joe Gross Special, but I lost interest in the project when I ran into some problems understanding the schematics for the nFlex board. I do not know anything about electronics. I recently ran across a simpler design (Circuit 2), which got me interested again. I intended to go back to the Joe Gross Special, but I did not have all the electrical parts. I went to Radio Shack, and they did not have the parts I needed. They did have the parts to build Circuit 2, although the silicon diodes are 1N4005 rather than 1N4007. The capaciter is 1,000uF, 35V, which is the largest they had. Radio Shack is no longer the goto place for electronic components.
The light went together without any problems, and I rode around for about 10 minutes before I glued the back plate on with J-B Weld. I could not feel any heat on the outside of the light, so I assume it will continue to work without melting down. I intend to test it for an extended period of time before I ride a 300K brevet scheduled for April. When I did the test ride, I had both lighting systems on the bike and was able to compare them. The LED light beam is not as focused as the halogen, but it is a lot brighter. The halogen bulb has a few hours on it, so a new bulb would probably be brighter, but with the LED, I do not have to worry about the bulb browning out and having to be replaced. The LED beam also seems to falloff quicker than the halogen, but it may just appear that way because the beam is wider. The light does flicker at walking speed, but as soon as I start pedaling the beam is steady.
I do not think I saved any money building the light, in part because I bought some extra parts that I had to mail order because I did not want to have to order again if I screwed something up. If the first light continues to work, I will use the extra parts to build another one.
Old lighting system on the Romulus
(button LED is partially behind the left headlight)
New LED light
New lighting system
Well that filled the day....
6 days ago