where to mount dynamo magnets?

souter · 16-09-2010 11:27pm #1

Just go a set of reelight.com front and back and the instructions are a bit vague on where to position the magnet/generator combo, i.e. close to the hub or the rim?

FarmerGreen · 17-09-2010 10:21am

Heres a review of the gadget :-
http://www.everydaycycling.com/edc/news/archive_news_864.aspx

souter · 17-09-2010 12:08pm

ta, that would be the original model (I have the capacitor for steady light), I guess the originals were hub mounted so that's probably where to go.

Morgan · 17-09-2010 12:14pm

They have to pass right beside the lights don't they?

cdaly_ · 17-09-2010 12:41pm

I'm assuming Souter has the version where you have a generator on the wheel/fork and the lights up on the bars/saddle.

I would be inclined to mount the magnets fairly close to the hub such that the generator sees a duty cycle close to 50% (ie. There's a magnet passing as often as there is clear space passing). If you mount the magnets near the rim, the generator will 'see' magnet for much less time per revolution but will presumably get a higher voltage spike when a magnet does pass. Closer to the hub there will be a lower voltage but for longer time. I presume, given that the thing charges a capacitor which, in turn, powers the lights, you'll end up with the same overall charge either way...

Seaswimmer · 17-09-2010 2:16pm

I have a few sets of these on the kids bikes and you should mount them so that the magnets pass within a mm or 2 of the generator but also the generator should not be at the extreme of its adjustment. you should be able to move the generator in or out a bit as required. the main problem i have found is that on a round fork/seat stay the generator can rotate a bit and the lights will not work as the magnet passes to far away. Aslo if you mount them too near the hub you may find the wire is not long enough to reach the handlebars or seat post comfortably.

souter · 23-09-2010 2:44pm

I mounted them as near the hub as I could, also made sure they are on the trailing edge of the stay relative to forward wheel motion e.g. the front is on front of the right fork to avoid the mudguard struts, rear is on the bottom of the left chain stay for similar reasons.
Able to mount the generators c. 5mm from the magnets - any closer and they have to be super tight otherwise the magnets will tend to pull them into them over time.
End result is they are putting out much more light.

where to mount dynamo magnets?

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