Dyno Hub

[willem]

There could be tiny differences in theory. In reality I cannot possibly imagine you could feel them. For many people (not for me) it is hard enough to notice that the light is on at all. Maybe the brighter light unknowingly encourages you to ride faster.
Willem

 

[yello]

Maybe the brighter light unknowingly encourages you to ride faster.

Yes, I could buy that.

Also, thinking about it practically, I'd say that I mostly use my lights at the end of a ride rather than the beginning (I'm not an early riser as a rule). So, consequently, my legs will be tired when the light comes on.

 

[andrew_s]

The Cyo is 6 volt, not 6 watts.

What makes you think a Cyo is 6 volts?
Hub dynamos don't supply 6V, they supply 0.5A. It used to be fairly common to use two lights in series, with the hub giving 12V.

 

[Tombo 707]

These Dyno hubs are starting to sound like to much like hard work. I am looking for some possitive feedback. Can someone please recomend a good L.e.d. battery light. The winters are long here in Shetland and I am in need of a good front light.

 

[vernon]

These Dyno hubs are starting to sound like to much like hard work. I am looking for some possitive feedback. Can someone please recomend a good L.e.d. battery light. The winters are long here in Shetland and I am in need of a good front light.

Disregard all the squabbling over details.

A decent dyno hub - Shimano or SON coupled with a decent LED light from Lumotec IQ Senso Fly or Cyo combination will more than meet your needs. Once fitted you will be able to forget about the lighting system and will not need to buy another battery.

Forget about drag - you wont notice it.
Forget about volts and amps just connect the lamp top the dyno hub and pedal away.

No electrical theory is needed.
No mechanical theory is needed.
Forget about any units of brighness the lamps above will be bright enough.

 

[asterix]

Here is a good guide to everything you need to know about life, the universe and dynamo hubs. (I lied about the first two).

 

[yello]

Disregard all the squabbling over details.

That wasn't squabbling! You wanna see real squabbling! You ought to get out more

No electrical theory is needed.
No mechanical theory is needed.
Forget about any units of brighness the lamps above will be bright enough.

100% in agreement. That was my approach.... in the end. At first, I read and tried to understand (I thought that was what you were supposed to do) but then it all just got a bit boy's toys, so I gave up.

People said hub dynos were great, and I could understand the benefits, so I tried one and am sold. People said the Cyo was breathtakingly good, so I bought one and they were right!

You don't need numbers to know they work. The question is whether it suits your needs.

 

[Andy in Sig]

SON are the best you can get and they are just a matter of fit and forget.

 

[Yellow Fang]

I had a Schmidt XSON dynohub fitted to my Brompton. The dynamo itself is excellent. My main problems have been with wiring up the lamps and the front lamp bracket, but these are largely problems to do with the design of the bike. The back lamp used to cut out a lot, but this was due to it not being earthed properly. The wires to the back lamp sometimes got disconnected, but this was mostly due to them being tugged while folding the bikes. Hopefully, a zip tie will sort out that problem. I used to have problems with the front lamp and lamp bracket. It used to stop me using my front pannier, and I had to swap over my lamp for one of the circular Busch & Muller lamps. As I said, the dynamo itself is excellent. I don't notice any drag. I've used bottle dynamos in the past, and these were never satisfactory. Any bulges in the tyre used to cause the lamp to flicker, and the bulbs were constantly blowing.

 

[willem]

For those of you who want the theory after all, the formula is Amp=watt/volt, or with the "normal" numbers 0.5=3/6 If you connect two 6v lights in series, this becomes 6+6=12. So the numbers in the equation become 0.5=6/12 In short, you can have two lights at full blast. There is no free lunch, however, since it is you who has to produce these watts. Your output has to increase from roughly 5 watt (to produce 3 watt electricity) to roughly 10 watt (to produce 6 watt), assuming 60% efficiency. The second snag is that for 12 volt the hub only produces this at higher speeds.
The formula is the same as you can use e.g. to calculate what electrical oven will go with which fuse. A 10 amp fuse will be blown by any oven of more than 2400 watt (still on 240v in the UK?).
Willem