Kickstarter Light technology
 

Excuse the cross-post, I stuck this over on the Commute forum as well, but I thought this worth bringing to the attention of the folks here...
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Has anyone seen this http://www.kickstarter.com/projects/...ergy?ref=live?

It looks pretty good - I think I'll jump in on this one...

Lawrence

Don't waste your time nor money.

that seems pretty cool.

I've backed a cool aluminum pen that should ship this month. This might be the second project I back.

I am wondering whether I could interest you in this bridge, given 'luvr' be that Eiffel Tower, I have on sale:).

$25 and you get a shirt with your new lights.

1. 25 + YOU SELECTED
2. The Shirt: Get a personalized high quality functional shirt with the project logo and your name.
3. Est. Delivery: Apr 2012

The idea sounds kinda cool but there's absolutely no specs as to light output. Not even a guess-timate!

just by the looks somewhere in 100-150 lumen range.. pretty great idea, but not bright enough for most on here.. If he makes wonder what the price point will be.

It looks like it could be a viable replacement for hub dynamos as LEDs become brighter. Two 100~150 lumen LEDs already and output looks very good at slower speeds.

The light output is specified as 150 lm on their website.

This doesn't pass the "no free lunch" rule.

Both perpetum mobile and religion are here to stay;).

It states US$200 to the supporters on the link given.

Andrew

Regardless of whether their idea works well in practice, they clearly state that the dynamo produces drag on the wheel. I think their video even has a title card that says no free lunch. The magnets in the dynamo generate eddy currents in the rim, which create magnetic fields. On commuting, someone mentioned that this effect is very dependent on the distance between the rim and the dynamo, possibly requiring very true wheels.

Why should such essential issue be disregarded? There are tons of effects in nature that can generate emf, but they can be ridiculous in effectiveness of generating electric power compared to a basic dynamo.

They're suggesting the drag on the wheel is less the drag produced by a hub dynamo. In their video they compare (albeit not at all scientifically) their eddy current prototype to an Edelux driven by what I presume is a SON hub. I find it hard to believe that they could pull enough current out of the spinning rim to beat a SON, but then I am no physicist.

The brake light function is nifty, but the change in light output of the front light with braking might be weird/distracting. My own preference would be to have a fixed front mount for their 'kernel' and a cable to mount the light centrally (another criticism mentioned over in the commuting forum).

Perhaps one day they'll offer a stand-alone dynamo kernel that can be used to power third party lights.

um, except that braking with a conventional dynamo also causes a change in light output. :o

I guess I could get used to having more light when braking instead of less.

i don't like how the light is mounted on one side of the rim. it won't be very visible, if at all, from the opposite side.

Looks like you can mount one on each side if you like. Not a perfect solution, but it would eliminate the problem you describe.

One member has a review in another thread (linked here) but the creator has just announced an update to the Magnic Light which addresses a few issues.

http://www.kickstarter.com/projects/...ess-bicycle-dy

- Stand light
- improved optics
- improved internal circuitry
- options for tail light (quasi-brake light function improved)
- new/improved tooling

I like it. If I owned one I don't know if I would use it as a "stand alone" lamp but if used for back-up ( or in combo with battery lamps ) on extended rides....it could be sweet.

So, they took a Reelight and added a capacitor.

They are certainly NOT the "first compact contactless bicycle dynamo" - google Reelight.

Also, "no friction" is weaselly. There is certainly drag.

There's no free lunch. If you want X power to run a light, you need to draw that much power off the wheel, plus generator inefficiencies. Also, how is something that's just slapped on the side of a wheel going to be as efficient as a generator hub that's designed for the purpose?

While I don't propose to understand everything about the physics, according to what was written ( which I skimmed over ) the unit doesn't produce the same amount of power as a typical dynamo. It just uses the power it produces more efficiently ( see below ).

The thing I like about it is that it should be able to transfer easily from one bike to the next without much problem. They also include two different UI, ( for the rear ) one for the Germans and one for us which I think was a super smart thing to do. Now add to that; If I can buy one front light for less than $100 ( even if max output is about 160 lumen ) it sounds like the money spent may be well worth it if I never have to worry about having to run out of battery juice. For winter commutes it could be just the thing to give the dedicated battery lamp user some added peace of mind. :thumb:

No, there's more to it.

The reelights have magnets mounted to the wheel. These do not.

These are only the light unit with nothing else mounted to the wheel, which certainly is revolutionary. Apparently it works based on eddy currents generated in the rim?

With nothing else mounted anywhere but the light itself, they are more compact than the Reelight. Does that make their statement correct? That's a judgement call.

I don't quite understand how they've gotten this to work, but they seem to be shipping and I'm not hearing about people receiving theirs and saying it doesn't work as advertised, so ... it seems to be real.

Agreed. Though if we use the "the resistance that one surface or object encounters when moving over another" definition, their statement is technically accurate. But weaselly, as you said.

I don't know how efficient it is, but from what I understand hub generators are around 50% efficient, so if true (and I'm far from sure on that), there's room for improvement.

That said, they've not really given any information on how much electricity is generated and how much drag, so I have no idea if they are more efficient than that or not.

As a onetime owner of a Magnic Light, I can assure everyone that it is real, it works, and works pretty well. (I also wrote the review linked above.) It isn't magic as the name implies, but it does use a different means to generate power, one that you wouldn't expect.

The movement of ANY conductor generates eddy currents. In this case, the aluminum rim of your wheel is a rotating conductor and it generates the current. The magnets inside the light then move to generate the electricity that powers your lights. This works even though the rim is non-ferrous.

The real engineering feat here isn't the "magic" of the eddy currents, it is harnessing them in something small and light enough to put on a bike.

Look at the video on the kickstarter and you can see how this thing is built.

I don't think the name was intended to imply magic, unless it's in a different language. I have to say I was a skeptic, but a lot of us didn't think about the spokes playing in the physics of it. It's really a pretty amazing invention

Working through eddy currents is pretty neat. Using LEDs at half their rated output to increase efficiency is an interesting approach, and at the prices LEDs are at, it's not a bad decision if efficiency is paramount.

160 lumens is significantly substandard front lighting these days though. I wouldn't ride with less than about 200, and I wouldn't be happy at that. I really want 300 to 400 lumens up front at least, and that's in the easy parts of my ride. On the challenging bits, I want 800 or more.

... then what you want really isn't offered by any current dynamo-only lights of any sort that I'm aware of. I don't know of any dynamos that put out more than 3 watts, and at 100 lumens/watt for good modern LEDs -- that's 300 lumens. I mean, somebody could make a more powerful dynamo, but too much more drag and people won't like it -- even 3 watts from a 50% efficient dynamo is six watts of drag, which is going to be definitely noticeable.

And I imagine that you're aware of all of that.

That said, 160 lumens is way more than the reelights I have -- if it's 160 lumens steady, then that's well into the "help me see" category of light, where the reelights I have are strictly "help me be seen" lights. I'd guess that the reelights I have are maybe 25 lumens (well, the white front light) while flashing, and they're only on like 20% of the time (they flash), so an average of 5 lumens or so? (Just a guess, I haven't measured it.)

It is not quite like that. The rim ends up being partly ferrous because of a steel insert needed to close the circumference of the rim. The Magnic reacts both to the Eddy currents and to the insert. From my prototyping, the insert contributes both positive and negative effects. Negative is in making the positioning of Magnic difficult. Eddy currents repel while the insert attracts. If the Magnic were positioned too close to the rim, it might get stuck to the insert. Too far and the effects of Eddy currents could be too weak. I read a report of some owner claiming that it took him an hour to position the Magnic correctly. That could erase the convenience of moving the light from one bike to another, but I lack personal experience other than with a coarsely put together prototype.

Pretty sure there is no steel in an alloy rim. The pinning section is alloy too. Many rims are welded now as well.

Like most things, the initial set up might be hard - but once done all you do is click on and click off. I'd get two sets of mounts if I was swapping between bikes often.

Alibaba, Amazon and ebay can fix you up with 12V, 6W dynamos in singles or by the ISO container - all you need is a charge card number (preferably your own).