Originally Posted by
steelbikeguy
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I'd be interested in hearing from anyone who has used one of these systems, just to see what it was like.
Back in the days of incandescent bulbs, I built a system that used a Schmidt dynamo to charge a 5 cell nicad battery, and then used that battery to deliver a regulated amount of power to the Lumotec headlight. It worked fine, as long as the bike didn't spend much time stopped. Running the light at full power when stopped used a lot of power, and there was precious little spare power when riding with the headlight on, so recharging the battery was a very slow process. In the winter, when the light might be used on both parts of my commute, it wasn't uncommon to completely drain the battery. It didn't take too long for me to come up with a very different approach to standlights.
Steve in Peoria
I am clueless about those systems too. I worked in a bike shop in the 70s, we sold a few bikes with front Sturmy Archer dynohubs, but I can't really remember anything about them.
Maybe a decade or so ago, there was a guy on this forum that used four NiMH batteries in series and a rectifier and a USB plug as his USB charger with his dynohub. Basically the rectifier converted the AC to DC, charged up the batteries from that, and the batteries also buffered the voltage somewhat so that he said it worked as a USB charger. That could however push over 6 volts to a USB device, so not sure how well that worked out, I would not try it on any device I valued.
Thinking of that combo battery and USB thing, I built up a four AA cell NiMH battery charger by wiring in a rectifier and volt meter so I could plug that directly into my dynohub to charge the batteries. It worked the one time I tried it. But I decided after I made it that I should consider it emergency use only on a tour because all four AA or AAA batteries would have to be identical and start out with the same state of discharge to work well. I also did not have any overvoltage protection, so I would have to keep my eyes on the volt meter if I wanted to actually use it. I later bought a real USB charger that was designed to be powered by a dynohub and when I wanted to charge AA or AAA batteries, used a charger designed for that and was USB powered. I still carry my four cell emergency charger on bike tours, so if something in my regular system dies, I still can charge batteries when I am touring where there are no convenient plug ins.
But other than that, I just buy stuff and wire it together. Leave the hard core electronics to others.