Anyone seen these amazing lights?

[Hill Wimp]

May be worth asking any of our CC fellows in the US if they have come across them and what they think?

@Gravity Aided and @RWright may be able to help as they sound good.

 

[Davidc]

They're considerably more expensive than my Shimano hub dynamo and B&M lights for a lot less light from inferior lamp locations.

Won't be bothering until and unless the price is divided by 2, the output is increased, and the supplied lights are as good as B&M CYO60 front plus decent rear (60 Lux at 8 kph front, bit less rear), with standlight on front and back.

I'll also need to see drag figures. The Shimano produces 3w for 6w drag. There are better and there are worse hub dynamos at various prices.

 

[Rohloff_Brompton_Rider]

They're considerably more expensive than my Shimano hub dynamo and B&M lights for a lot less light from inferior lamp locations.

Won't be bothering until and unless the price is divided by 2, the output is increased, and the supplied lights are as good as B&M CYO60 front plus decent rear (60 Lux at 8 kph front, bit less rear), with standlight on front and back.

I'll also need to see drag figures. The Shimano produces 3w for 6w drag. There are better and there are worse hub dynamos at various prices.

I've thought about this. I reckon they work out cheaper than a wheel rebuild, coz they've gotta match. Zero drag and tbh they're not in a worse position than my Brompton dyno lights and they allegedly weigh a lot less.

The only thing stopping me ordering some is the lack of knowing anyone with experience of them hence an unknown quantity.

Edit: there's no drag figures coz there is no drag, it's workers off eddy currents, which is very clever.

Edit edit: no moving parts or wires in my mind, means they should last as long as the LED which, again in theory, is a bloody long time.

 

[Hill Wimp]

I've thought about this. I reckon they work out cheaper than a wheel rebuild, coz they've gotta match. Zero drag and tbh they're not in a worse position than my Brompton dyno lights and they allegedly weigh a lot less.

The only thing stopping me ordering some is the lack of knowing anyone with experience of them hence an unknown quantity.

Edit: there's no drag figures coz there is no drag, it's workers off eddy currents, which is very clever.

Its only lunchtime in the US give it a few hours and our US CCers will pop up.

 

[potsy]

....seriously dude?

Stop playing all innocent, I've seen you knocking hundreds of these out in your garage

 

[Rohloff_Brompton_Rider]

Stop playing all innocent, I've seen you knocking hundreds of these out in your garage

 

[Davidc]

I've thought about this. I reckon they work out cheaper than a wheel rebuild, coz they've gotta match. Zero drag and tbh they're not in a worse position than my Brompton dyno lights and they allegedly weigh a lot less.

The only thing stopping me ordering some is the lack of knowing anyone with experience of them hence an unknown quantity.

Edit: there's no drag figures coz there is no drag, it's workers off eddy currents, which is very clever.

Edit edit: no moving parts or wires in my mind, means they should last as long as the LED which, again in theory, is a bloody long time.

There is drag - conservation of energy and the laws of thermodynamics say there is.

The issue is how efficiently the system converts energy (kinetic) from the rotating wheel into energy (electrical) for the LED. Their video on the development describes how it works, and having now measured the electrical resistance of my bike wheels to give an approximate resistivity for the alloy, and from that an estimate of the loss from the eddy currents they're using to make it work. (Assuming good quality high strength magnets are used) I think the conversion will be around 50% efficient if I've done the calculation right. That is very close to my Shimano hub dynamos so if realised looks very respectable.

Clearly there's no drag when the lights are off the bike! For hub dynamos I've checked the spin time of the wheel compared to a normal hub with no current drawn. Not quite a true reflection because of the momentum of the hub itself, but there's no measurable difference on the Shimano or a SON one, so again not very different there.

The one issue left is what happens when you go very fast. They say they're using the magnetic field from the eddy currents in the rim produced by their fixed magnets. I haven't quite convinced myself of how that's producing the varying flux to generate the lighting current, but the field must increase with speed. I can't see how in this case the current from the system will be self limiting in the way it is from a generator of the conventional bike type. If I'm right there must be a speed at which the LED goes pop.

Anyone else fancy thinking about the physics? I'm more than happy to be challenged or corrected!

Edit: back to your post - I think it's time you got into wheel-building BromptonFB, given this and your other thread.

 

[Rohloff_Brompton_Rider]

There is drag - conservation of energy and the laws of thermodynamics say there is.

The issue is how efficiently the system converts energy (kinetic) from the rotating wheel into energy (electrical) for the LED. Their video on the development describes how it works, and having now measured the electrical resistance of my bike wheels to give an approximate resistivity for the alloy, and from that an estimate of the loss from the eddy currents they're using to make it work. (Assuming good quality high strength magnets are used) I think the conversion will be around 50% efficient if I've done the calculation right. That is very close to my Shimano hub dynamos so if realised looks very respectable.

Clearly there's no drag when the lights are off the bike! For hub dynamos I've checked the spin time of the wheel compared to a normal hub with no current drawn. Not quite a true reflection because of the momentum of the hub itself, but there's no measurable difference on the Shimano or a SON one, so again not very different there.

The one issue left is what happens when you go very fast. They say they're using the magnetic field from the eddy currents in the rim produced by their fixed magnets. I haven't quite convinced myself of how that's producing the varying flux to generate the lighting current, but the field must increase with speed. I can't see how in this case the current from the system will be self limiting in the way it is from a generator of the conventional bike type. If I'm right there must be a speed at which the LED goes pop.

Anyone else fancy thinking about the physics? I'm more than happy to be challenged or corrected!

Edit: back to your post - I think it's time you got into wheel-building BromptonFB, given this and your other thread.

Ok Mr Pedantic..the drag is negligible compared to a hub dynamo. If you have calculated that the drag is similar, I think you've made some mistakes.

In regards to timing the time it takes a wheel to slow down when spun by hand....totally useless and irrelevant. The speed you'd need to get up to to measure any discernible difference, also needs you to overcome the magnetic pull of the the core and field. to do this you'd need a machine, for example a drill with a roller fitted to the end and very sensitive equipment.

There is somewhere on the Internet some in depth articles, and is quite in depth and takes all my knowledge to even follow the gist.

In regards to wheel building, why do you assume I can't build wheels? I've been doing it since the eighties where I learnt to build wheels quite regular, because I had Z rims on my BMX's and enjoyed doing tricks and stunts.


Here you go, here's one of them...

http://www.bikequarterly.com/VBQgenerator.pdf

And another...


http://www.ctc.org.uk/file/public/feature-hub-dynamos.pdf

 

[Davidc]

To do a proper comparison I'd need one of the units. As said I can only estimate the figures. The drag will not be negligible, it will be greater than the power delivered to the light and that in itself isn't negligible compared to the quoted total for a SON hub, discounting the likely higher power output of the SON. The Shimano hubs are not as good but still offer quoted conversion efficiencies upwards from 50%.

For your information the comparison of drag was done from a rotation rate shown as 30.0 mph on the same bike computer down to stopped, with the bike on a workstandand I should have written significant not measurable. The time difference from the plain hubbed wheel was least for the SON, but it was brand new. Neither difference was great.

The reason for thinking about what's involved in these lights, hence my previous post, is that I suspect that they work but that the advertising is mainly hype. I accept that I may be wrong and if I am I expect to see them developed further and measured performance figures published.

It is interesting to note that the manufacturer's video offering a comparison with a hub dynamo doesn't actually offer any such comparison.

I apologise for the assumption that you don't build wheels, made on the basis that on the other thread you appeared to have rejected the option. From experience you are in a small minority, hence the error. You clearly learnt as I did, from necessity. Good.

 

[Rohloff_Brompton_Rider]

Well, I'll guess we'll just have to agree to disagree re the drag. Tbh I just wanted to ask if anyone had physically seen one or used one, not get dragged into drag issues (see what I did there?).

At some point in time PC's were thought to be a fad and went thru crappy quality phases (remember windows 2000?). I hope that these deliver what they purport to and make it into mainstream.

 

[andrew_s]

I've got one of the rear lights. Time will tell, but as far as short term impressions go, here it is...

I have a regular dynohub front light so there didn't seem much point in the fronts, and the beam shape isn't good, but the rear is much brighter than a regular dynamo rear.

The drag is lower than a hub dynamo, but only because there is less power being generated. I don't expect the overall efficiency to be any higher than a decent hub dynamo, and it may even be lower. You can get a lot of drag from eddy currents and magnets - they used to brake Japanese Shinkansen Bullet Trains with eddy current brakes.

The best mounting options are those available on the website - using the double front mount that attaches to the brake bolt, via the caliper brake bolt, or onto the cantilever studs. The stay/fork blade band-on mount is definitely second best as it's difficult to get the light fitted both close to the rim (3-9mm required) and rigidly. As a result, the rear won't fit well on a bike with a rear rack.

A fuller review by someone in California here: http://bike.duque.net/review-the-magnic-lights.htm

How it works:
There's a rotor inside with radial magnets on it, and the eddy currents in the moving rim drag the rotor round. The power is extracted by putting a coil round the spinning magnets.
See demo video here http://s168.photobucket.com/user/Vankoff/media/Magnic/MagnicMovie.mp4.html
This has a nut with 6 sets of magnets on the faces, with the outside poles alternating N & S.

 

[Rohloff_Brompton_Rider]

Couldn't help myself....I knew I was right...

Magnic Lights are very bright, lightweight, incredibly efficient bike lights that use no batteries, are self-contained, and don't require building a wheel around a dynamo hub. This makes them a game-changer, I dare say historic because I think someday most bike lights are bound to work similarly. All you do is position the small light units in proximity to any normal metal bike rim, and they work. Unlike superficially similar "be seen" products like Reelights, these don't require mounting magnets in your wheel, and are plenty bright enough to be your only lights. This is the jaw-dropping part: just the motion of the metal rim itself, not magnetic or even necessarily ferrous, is enough to power the lights. No contact or noise, no external parts or wiring, lighter weight and an order of magnitude less drag than the very most expensive dynamo hubs. There's no such thing as free energy, but any resistance created by Magnic Lights is utterly negligible, even with a wheel turning free in a stand, for minutes. They boast the brightest dynamo taillight on the market (aim carefully please!), and while the headlights don't measure up in brightness or beam shaping to the best available, they aren't too shabby either.


From here...

http://clevercycles.com/blog/2013/08/13/game-changer-magnic-light/

 

[Rohloff_Brompton_Rider]

I've got one of the rear lights. Time will tell, but as far as short term impressions go, here it is...

I have a regular dynohub front light so there didn't seem much point in the fronts, and the beam shape isn't good, but the rear is much brighter than a regular dynamo rear.

The drag is lower than a hub dynamo, but only because there is less power being generated. I don't expect the overall efficiency to be any higher than a decent hub dynamo, and it may even be lower. You can get a lot of drag from eddy currents and magnets - they used to brake Japanese Shinkansen Bullet Trains with eddy current brakes.

The best mounting options are those available on the website - using the double front mount that attaches to the brake bolt, via the caliper brake bolt, or onto the cantilever studs. The stay/fork blade band-on mount is definitely second best as it's difficult to get the light fitted both close to the rim (3-9mm required) and rigidly. As a result, the rear won't fit well on a bike with a rear rack.

A fuller review by someone in California here: http://bike.duque.net/review-the-magnic-lights.htm

How it works:
There's a rotor inside with radial magnets on it, and the eddy currents in the moving rim drag the rotor round. The power is extracted by putting a coil round the spinning magnets.
See demo video here http://s168.photobucket.com/user/Vankoff/media/Magnic/MagnicMovie.mp4.html
This has a nut with 6 sets of magnets on the faces, with the outside poles alternating N & S.

Thank you for that. What's the build quality like? And would you buy again?

 

[RWright]

Its only lunchtime in the US give it a few hours and our US CCers will pop up.

This is the first time I have seen these, they look interesting. I first looked and thought they rubbed the wheel and immediately was not interested but if they don't touch the wheel that would be good. I just wonder about possible road or trail debris and its affect on them. I am thinking they would be better for road use. Will be interesting to hear from people using them.

 

[Hill Wimp]

This is the first time I have seen these, they look interesting. I first looked and though they rubbed the wheel and immediately was not interested but if they don't touch the wheel that would be good. I just wonder about possible road or trail debris and its affect on them. I am thinking they would be better for road use. Will be interesting to hear from people using them.

We were banking on you knowing something about them or another US cyclist as the company are from Portland Oregon.