Thorn Cycles Forum
Technical => Lighting and Electronics => Topic started by: iwicom on June 12, 2006, 11:28:42 PM
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This is a new generation bicycle light system.
No battery is needed, no friction on any parts of the bicycle. The lights flash regardless speed of the bicycle and weather conditions (unlike normal dynamos!). Very bright.
More details on http://www.freelights.co.uk
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Doesn't seem to be that new to me, hub dynamos are very similar. Hub dynamos don't have friction of rollers on the tyre, and only have the resistance of turning a magnet inside a coil (like they say at that website). Didn't check what they want as a price for it, so can't compare it there. Also I don't know how easy it would be to fit, but as they seem to describe it as a system you would fit and leave, is that more trouble than getting a wheel built with a hub dynamo (when your wheel needs rebuilding if you can wait)? Also can it only drive the LEDs they use in that system? Or does it have more power?
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2 things
1) It MUST have some form of resistance becasue it generates electricity.
2) What they mean is it doesn't create MUCH resistance. That's because it doesn't generate much electricity.
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Of the 2 or 3 sets of these lights I know of in service all of them have had durability issues and simply don't put out enough light to be particularly useful. I don't know any that remained in service after a few months of use.
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Reelights do this much better
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Hi All,
I've been keeping an eye on these things the last six years or so. While the idea hasn't really taken off, neither has it gone away. The promise of no-maintenance, battery-free automatic lighting has universal appeal. That's why I went with a SON28 and a Cyo with auto-sensing feature. ;) With this setup, I can actually see as well as be seen. Drawbacks are the cost, weight, and need to have the dynohub built into a wheel.
The Reelight ( http://www.reelight.com/ ) is still with us, but doesn't look as bright as I might have hoped, given what I see on video:
http://www.youtube.com/watch?v=kE1lt4jN51M&feature=player_embedded#! Maybe best suited for being seen in darker environments; it appears they wash out in brighter ambient urban night-lighting. The don't appear to cast a focused beam to see with, either. Any forum members use these?
Now, there's something truly new on the market, both in concept and execution, and it looks promising...
The latest development in no-contact, battery-free lighting is the Magnic Light, whose developers are about halfway to their Kickstarter funding goal with about three weeks to go (I have no involvement with it). To read more, go to their Kickstarter development page:
http://www.kickstarter.com/projects/dynamodirk/magnic-light-get-new-energy
The Magnic is not an electro-magnetic induction generator in the same way as the Reelight because it doesn't depend on magnets attached to the spokes. Rather, it apparently works by using an extremely powerful magnet to create and amplify eddy currents generated by a passing (metallic) wheel rim. For the principles involved, see:
http://en.wikipedia.org/wiki/Eddy_current
http://physics.bu.edu/~duffy/py106/Electricgenerators.html
http://en.wikipedia.org/wiki/Faraday%27s_law_of_induction ).
The Magnic is currently on-display this weekend at the Fahrrad trade show in Essen, Germany, so you can see it in operation there if you're nearby. The developers are Strothmann-Spiele GbR in Borgholzhausen, Germany. Project leader Dirk Strothmann is a game inventor ( http://strothmann-spiele.de/index_en.php ).
Though it looks compelling in their presentation, there are still bound to be some losses due to magnetic resistance, and there is currently a fancy carbon-fiber case for early investors, but as yet no standlight, though one is in development. It must use expensive neodymium magnets in the case; see experiments here:
http://www.kickstarter.com/projects/dynamodirk/magnic-light-get-new-energy/posts/178039
In mass production, it could be the product many are looking for. It'll be interesting to see what the future brings.
Those interested in the principles of electromagnetic inductive power generation might enjoy the explanations given in the classic 1914 Hawkins Electrical Guide, which has now passed into the public domain. Volume links here: http://en.wikipedia.org/wiki/Hawkins_Electrical_Guide , aka Danneaux's current (sorry) bedtime reading.
Best,
Dan.
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This is hopefully the future and should be built into the bike frame.
Then maybe I will be able to see and be seen by the local paper delivery teenagers on dark winter mornings before they run me down !
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A remarkably bright lighting system! Probably not feasible to build it into the frame as, apart from cost, the electro-magnetic forces may be distorted.
For use on a touring bike, the rear brake-bolt mount is completely useless - hidden by panniers.
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For use on a touring bike, the rear brake-bolt mount is completely useless - hidden by panniers.
We're in complete agreement there, Pete. Somewhere on the Kickstarter site, the developer says it would be possible to leave the generator/pickup in place on the brakes and use it to feed a remotely-mounted light. He also mentioned this wasn't as aesthetically pleasing due to the wiring involved, but I can't see the thing being useful otherwise! (at least not for tourists, as you say).
Hoping for a portable fusion generator,
Dan.
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the developer says it would be possible to leave the generator/pickup in place on the brakes and use it to feed a remotely-mounted light. He also mentioned this wasn't as aesthetically pleasing due to the wiring involved
It kind of staggers me that a German bicycle developer would take such a stance. It's very much the norm for the bikes that most people ride in Europe, and Germany too, to have rear racks, rack-mounted lights and often to use panniers and/or child seats. Germany has the most stringent bicycle lighting standards, requiring lights that work well and are correctly mounted for visibility.
Why on earth would you let aesthetics determine your lighting design ?? ???
FWIW, I think the 'aesthetics' of the light is pretty terrible. But if it works very well, giving a good beam, I'd consider buying it. Needs to be a visible beam though.
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I had the freelights on my bike at uni in Manchester. Admittedly a rainy city but they only lasted about 3 weeks before they filled with water and stopped working. Don't buy them.
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Given the obstacles and high costs facing a startup, I think the inventor would do better licensing the idea to a larger, established maker like B&M. who have the production capacity, distribution channels, dealer network, name recognition, and advertising capacity already in place to make a go of it.
I do see there is a "brake light" effect by mounting it on the brake arm and it getting brighter when the brake is squeezed. The inventor mentions the effect will work up to 5mm away from the rim, so there must be an optimum distance for balancing magnitically-induced drag with power production. I'm thinking a mount for v-brakes might produce better results than a variable mount, as on a sidepull.
If the generator could be produced in a standalone unit with terminals for connection to, say, a B&M IQ CYO R and a Toplight Line Plus (each with a standlight and proven good beams), that would really be something. To be fully viable as a substitute for my SON28, it would have to produce as much energy and be as effective at providing light to see by and sufficient electricity to charge my gadgets. If it did less than that for the same price, I'd have to pass. If it did as much for the same price or less and is lighter and doesn't have to be built into a wheel, the guy's got a winner.
Best,
Dan.
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I think this idea is a loser. The implementation is ugly and poorly designed on so many fronts, I'll give you fifteen quid just to take those lights away and dispose of them responsibly. Just the idea of covering the magnets on the spokes with electrician's tape is enough to give me heartburn.
If you want self-powered warning lights, buy the Reelights.
The very idea that these Freelights can compete with a hub dynamo and properly designed lamps which light up the road is ludicrous.
We can give the designers a tip. To start with, fellers, decide whether you're designing lights for commuters, tourers or roadies: this defines the type of light (to be seen by, need for flashing, to see by) and fixes the output parameters, as well as the desired fittings and length of wire you must supply. Your present arrangements merely demonstrate that you don't know who you're trying to sell your product to, or why.
I still have hopes of the brake light effect, which Dan also notes, but we all know that it didn't take the market by storm in the hands of such renowned engineers and marketers as BUMM when they tried to market a properly developed and engineered system, nothing Heath Robinson about it, called DIWA.
Sorry.
Andre Jute
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Back to the top :)
Reelight seem to have developped a nice new set: RL700.
I used to have the poor-man-reelight set (SL100) installed on my old bike. I may fit them to the Sherpa but they are only to be seen, not to see. These new sets may be better.
Any comments on these?
Cheers,
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Hi Blue!
It would be great if the new Reelight 700-series produced and directed light in a usable way. The new headlight apparently uses a rear-facing 1-watt LED and shaped reflector, which is encouraging, but I haven't seen any photos of beam patterns.
It would surely be nice if enough light was provided to actually see by, rather than just enough to be visible to traffic as a safety light.
Perhaps some objective reviews or tests will be forthcoming soon.
Best,
Dan. (...who is always hopeful about such things)
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I did try out a Reelight "SL550 Steady Rear Light - No Standby" version.
My initial impression was that they were *adequately* constructed.
But they were definitely not in the same constructional league as other types of rear light at the same price point.
After my usual "adapt any new product that comes into my grubby little mitts", I managed to fit them to my bike
They did work, but the supposedly "steady" lights definitely pulsed in brightness even at quite high wheel revolution rate.
They came with just 2 spoke-mounted magnets. So I ordered 2 more. They arrived but they were no-longer metal+plastic construction. Instead they were magnets encased inside an all-plastic mount.
And the new magnets were thicker and so could not allow all 4 magnets to pass equally closely to the frame (in my case rack) mounted induction coil.
I complained about the different style of magnet to Reelight and they sent me 2 more magnets (of the all plastic style) free-of-charge. Kudos to them for this.
However even with 4 magnets (all plastic mounting) the light was still fairly weak.
Also the plastic mounts all deformed quite a lot so, although the magnets were all equally spaced from the induction coil they could not be as close as the metal+plastic mounted magnets
With 2 magnets and even more so with 4 magnets the energy-conversion from kinetic to electrical is definitely not entirely "friction free*. The magnets are clearly retarded as they pass the induction coil.
So my overall opinion is: Interesting idea, but the light is not good enough and the energy drain and installed weight is not sufficiently negligible for this weak light to be worth it.
Maybe the Reelights that are intended to flash (with or without the "standby" functionality) are a better see-me safety light. The steady version is definitely not really worth the cost + installation effort IMHO.
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Ian
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Ian!
Thanks so much for your very informative and well-written report on the Reelight steady light w/o standby. I think it was a very fair presentation and evaluation based on your personal experience. A real help to all considering such a lighting system for themselves.
Wow -- even photos! A very nice job!
Best,
Dan.