Thorn Cycles Forum

Technical => Lighting and Electronics => Topic started by: rualexander on October 29, 2013, 02:43:15 PM

Title: Rim dynamo
Post by: rualexander on October 29, 2013, 02:43:15 PM

A link from someone on the ctc forum has brought the concept of rim dynamos to my attention, something I have not come across before.
This one looks an interesting alternative, albeit quite expensive at €150.
http://www.velogical-engineering.com/rim-dynamo-en

Title: Re: Rim dynamo
Post by: triaesthete on October 29, 2013, 09:13:38 PM

Thanks for posting Ru. A very interesting development. It's amazing just how small it is. I think I can feel a use coming on for all those redundant front hubs left over from Schmidt conversions  :)

A little more enlightened in at least 3 ways
Ian

Title: Re: Rim dynamo
Post by: jags on October 29, 2013, 10:36:24 PM

that looks super cool 8)

Title: Re: Rim dynamo
Post by: Andre Jute on October 30, 2013, 02:39:16 AM

Quote from: jags on October 29, 2013, 10:36:24 PM

that looks super cool 8)

1.7W at 20kph isn't impressive, and it'll flicker your LED probably to a pretty decent speed because there's no rectification. They've sacrificed everything for low mass, and inflated the price. Maybe they'll catch a few roadies in their net, but I wonder how many commuters or tourers will read past the price.

Title: Re: Rim dynamo
Post by: Danneaux on October 30, 2013, 03:20:59 AM

Hi Al!

There's been any number of these over at Instructables and the other DIY/Make sites using old stepper motors from printers.

Several examples here:
http://hackaweek.com/hacks/?p=595
http://www.instructables.com/id/Bike-Generator/
http://www.instructables.com/id/Bike-light-generator
http://www.autospeed.com/cms/A_111296/article.html

The problems of proper sealing and and maintaining roller friction in the wet are a concern, but the process of "rolling your own" can be a lot of fun.

Best,

Dan.

Title: Re: Rim dynamo
Post by: Andre Jute on October 30, 2013, 06:07:51 AM

Nice work, Dan.

Those who want, instead of a stepper motor, to start with a known-good sidewall dynamo converted to rim use, say because they have one in their junk box, can easily adapt it for rim duty for less than a quid/euro/dollar in a quick visit to the motor factors to buy an O-ring of the right size.

Title: Re: Rim dynamo
Post by: jags on October 30, 2013, 09:40:48 AM

ah well to good to be true.i live in hope. ::)

Title: Re: Rim dynamo
Post by: il padrone on October 30, 2013, 10:10:51 AM

Much prefer the simplicity in use of a good dynohub wheel.

Title: Re: Rim dynamo
Post by: Danneaux on October 30, 2013, 06:45:49 PM

Quote

Much prefer the simplicity in use of a good dynohub wheel.

Me too, Pete. Owning one was a longtime goal and I've not been the least bit disappointed now I have one.

Best,

Dan.

Title: Re: Rim dynamo
Post by: Andre Jute on October 30, 2013, 07:57:01 PM

Quote from: Danneaux on October 30, 2013, 06:45:49 PM

Me too, Pete. Owning one was a longtime goal and I've not been the least bit disappointed now I have one.

My opinion, too. But, if you mixed with the weight weenies among the roadies, they'd be horrified at the hub dynamo's mass. There may be a market, possibly even a premium market, among the roadies for such a lightweight rim dynamo. But I know many who are so mass-shy that they ride in the dark without a lamp, or with a worthless little coin-cell operated flashing  attached to their helmet or clothing so that it isn't even ever optimally pointed.

Title: Re: Rim dynamo
Post by: rualexander on October 30, 2013, 10:16:42 PM

Someone has tried out this dynamo here http://www.bentrideronline.com/messageboard/showthread.php?t=96734
Seems to work reasonably well.