More on dyno hubs

[FLYBYU44]

If you read my other post I was talking about building a sidewall dynamo powered LED light. After reading up some more on sidewall dynamo's I realized that this wouldn't work. I do a vast majority of my riding in the winter with snow, ice etc. I think that I would have a serious problem with realiability. So now I'm looking at this:
http://harriscyclery.net/itemdetails.cfm?ID=1547

For me $89 is a ton of money to spend on what is essentially an experiment. So I want to know some of the expert opinions on here, and how this would work. As stated before I know next to nothing about this stuff, but I'm learning fast. I want to run a 1 Watt or higher LED off this, I also want to have it so that it will run for a minute or more while stationary. For this I gather I will need to wire in some capacitors? Also I will be using this hub on a 20" wheel, will that damage it or anything?

 

[Calina]

The Shimanos are good hub generators for the price. Of course the Sons are better but way more expensive. For hub generators, you also have to figure in the price the cost of building the wheel unless you can do that yourself. If I remember correctly Harris cyclery explains somewhere on their site how to build a wheel.

 

[PhxCycler]

Here is a link to a report on generators. It has some information specific to 20" wheels as well.

http://www.vintagebicyclepress.com/VBQgenerator.html

 

[rideatnight]

If you're that worried about experimenting, just get a MiniNewt.X2 or something along those lines. The cost will be around $180, and you'll get at least 3 hrs runtime. I doubt that you're commuting for longer than that.

another resource: http://www.peterwhitecycles.com/lightingsystems.htm
You could just drop the bones on an inolight and a SON20 wheel.

Here's the breakdown on what I spent building my dynamo light so far:

Shimano 3N71 dynohub - $90 (team pro-deal price)
Rim & Spokes - $40 (I built the wheel myself)
LEDs & lenses - $50
Housing - $15
Stuff to built a standlight for the light - $15 (newest experiment)
30-40 hours of research, building, testing, rebuilding, more research

So for that, what do I get? A very bright light that I never have to recharge/worry about batteries.

Notice that I wheeled and dealed my way to keep the price around $200. I spend 10-15 hours a week training to get these kind of deals (and win races). So common-man prices would put this project at around $350 - $400.

But man oh man, do I love my light. Just pop it on, toss on the dynohub wheel (out of the collection of spare wheels) and go. I would still love it if I had paid $400 for it, because I doubt I'll have to drop money on a light for another 10 years or so.

 

[PeLu]

Also I will be using this hub on a 20" wheel, will that damage it or anything?

No, you get more voltage out of it when you want, but you pay more effort for it. In some cases it might be a problem when you are going very fast.
Special small wheel dynamos are only available from Schmidt (I do have several different models).

BTW, complete hub dynamo front wheels are usually sold on German ebay for 40 euro or less.

 

[n4zou]

You might want to consider the Pioneer E-generator light kit available from the link below.
http://www.abs-sports.com/

It attaches to your rear wheel axel and spokes so you do not need to build a new wheel around a dynamo hub. This saves you a considerable amount of money and allows shifting the light system to another bike in the future. It's rated for 20" to 29" wheels so you don't need to worry about running it on a 20" wheel. The kit comes with high quality German approved lights so you know this kit is not going to fail after a few months. The dynamo is a pioneer ELS-100. Here is the link to the German language report.
http://www.enhydralutris.de/Fahrrad/Beleuchtung/node43.html
If you run it through a translation machine from German to English it reads like a horror story. In reality it's not so bad. Granted; it's not a high quality German hub that would cost you upwards of $400. It's still much better than any bottle dynamo you might consider mounting. The part of the translation that puts everyone off is the "sanding" of the magnets as they slide on a Teflon pad with the coils and poles behind that Teflon pad. This is no big deal and will last for many years and would most likely outlast you! What's going on is the magnets have spring pressure keeping them properly aligned and as close as possible to the poles ensuring steady current production. Anyway if you look closely at the test results you note the production of 770mA of current at 16.2 Km/h with a 700c wheel. This would easily drive a 3-watt LED rated at 800mA. This provides a much greater amount of light with no need to worry about too much current produced to shorten the lifespan of that LED. Personally, I would use the lights that come with the kit until the headlight bulb burns out (which might take several years) and then replace it with an LED headlight. The taillight is an LED unit with a stand light feature so it stays illuminated for several minutes after stopping.

 

[Martin]

For ways to connect the LED(s) to the dynamo electrically, I have just put up my new page. You've asked for stand light, I haven't published a circuit with this yet but will do some day..

 

[n4zou]

You might want to consider the Pioneer E-generator light kit available from the link below.
http://www.abs-sports.com/

After some more research I discovered the drag produced by the pioneer els-100 with the lights off is not much lower than with the lights on! You might as well leave the lights on all the time making yourself more visible to traffic just as seen on motorcycles. I've made the decision not to purchase the E-generator kit.