Evening STW,

I am planning a big ride next year, and need to sort out a hub dynamo. Mainly for lights, but also to charge up MP3 player ect.

I know its possible to do, as i have seen it done before. As most electrical bits (small ones) only need about 5volts to charge.

Anyway, just wondered what people use, and any good/bad points about it?
I have never used one, so any input would be great.

Cheers
Josh..

The ‘best’ is probably a Schmidt SONdelux. But it costs about £100 more than the Shimano…
Something like the Shimano DH-3N80 would work fine,and is only slightly heavier, maybe slightly more drag (but still not noticeable). Or the Alfine dynamo hub if you’re using discs.

Charging things from it is a bit more complicated. Busch & Muller make the E-Werk, which can provide 5V, and a variety of connections, but it costs over £100.
There are variety of cheaper devices to do a similar thing, but I don’t know if they are any good.

Josh – there’s some german electrickry for providing a stable USB voltage

I plan on mating it with one of these to provide a bit of a buffer / extra juice to power an iPhone and a Garmin Edge

I’ve got a Shimano Nexus dyno hub, 2.4v output I think, wired up to a LED front light that produces a surprisingly decent output. Not battery powered LED by any stretch, but not bad for dark rides.

Heavy, can’t comment on drag, I just leave it on all of the time. The Schmidts are said to have less drag. I think there is more about hubs on the Sheldon Brown webpages.

Hmmm, interesting, might have to look into this an awful lot more over the next few weeks.

Craigw – I had seem the Schmidt unit, but was looking into the differences between it and the shimano stuff.

geoffj – Thanks for the links, can you let me know how it goes when you mate the 2 up?

I’ve got he dh 3n 80, significantly lighter than it’s predecessor the dh 3n 70(2)? and improved internals / laminating reducing all those bad eddies. Works really well. Have not tried a SON so can’t compare. Bought mine from rose in Germany, cheapest even after p&P took about 2 days to ship.

missingfrontallobe – Member
I’ve got a Shimano Nexus dyno hub, 2.4v output I think, wired up to a LED front light that produces a surprisingly decent output. Not battery powered LED by any stretch, but not bad for dark rides.

Heavy, can’t comment on drag, I just leave it on all of the time. The Schmidts are said to have less drag. I think there is more about hubs on the Sheldon Brown webpages.

The standard for hub dynamos is 0.5 A but voltage varies according to speed. They tend to be rated for about 3W but when you are going fast they are poking out much more!

Loads of info on the net. This is a good place to start even if your not interested in building your own head light it explains a lot with some watt vs speed graphs. Don’t take the numbers too seriously though as they are some odd bottle dynamos but it gives you ball park figures.

http://www.pilom.com/BicycleElectronics/DynamoCircuits.htm