Dynamo...

[lowranger]

Something like this maybe?
Shimano nexave fh c810 is a rear hub Dynamo. Don't know enough to recommend its suitability.

 

[Deleted member 4366]

BUT sorry to contradict a few comments on here. There is no detectable resistance in the hub ( yes I know by definition it's using energy, but I can't detect it

Please do the test I suggested and let us know the results.

 

[lowranger]

Please do the test I suggested and let us know the results.

When I said i couldn't detect it I meant as I was riding. We all know you don't get energy for nothing. Having the lights on does not slow the bike in any noticeable way and, as I mentioned, the range is so good if the Dynamo takes a mile off the range it's irrelevant.

Anyway to the test. Bit tricky to spin the wheel and start the stopwatch at same time. ( I dIdnt turn it upside down and my handlebar mirror gets in the way and I couldn't be bothered getting workstand out).

So an unscientific test but results as expected.
Brisk spin of wheel with Dynamo lights on 6.5 seconds. Same spin without lights on 7.5.

 

[Deleted member 4366]

7 seconds isn't very long. A normal wheel should spin for about a minute. Are your brakes rubbing?

Or is your dynamo giving a lot of drag when it's switched off?

 

[selrahc1992]

Ahh slight problem then. 10w banggood led light cannot be powered especially if rear light is added to circuit.

okeydokey, this should make heath Robinson proud, and I wouldn't mind doing it myself in the parallel universe where I live on farm on the coast on a Caribbean island and have a huge workshop and infinite amounts of free time): http://minisystem.blogspot.co.uk/2011/11/sturmey-archer-dynohub-magnet-upgrade.html

 

[awol]

How about non contact Magnic dynamo lights, not cheap like the aldi ones though.
http://www.magniclight.com/MagnicLight/index.php/en/

 

[Benjahmin]

How about non contact Magnic dynamo lights, not cheap like the aldi ones though.
http://www.magniclight.com/MagnicLight/index.php/en/

They look great(if pricey), but will they work with alluminium rims?

 

[Deleted member 4366]

How about non contact Magnic dynamo lights, not cheap like the aldi ones though.
http://www.magniclight.com/MagnicLight/index.php/en/

They're just a more expensive way of not getting something for nothing. It doesn't really matter how you take energy from the wheel and turn it into light. The result is more or less the same: if you want a lot of light, you introduce drag on the wheel. The whole idea of having an ebike is to use some power from a battery to assist the bike. It doesn't make any sense to use the bike to assist the battery. The only case where it would make sense would be to use wasted energy from the bike like using braking to charge the battery, but we don't do that for reasons too.

 

[selrahc1992]

They're just a more expensive way of not getting something for nothing. It doesn't really matter how you take energy from the wheel and turn it into light. The result is more or less the same: if you want a lot of light, you introduce drag on the wheel. The whole idea of having an ebike is to use some power from a battery to assist the bike. It doesn't make any sense to use the bike to assist the battery. The only case where it would make sense would be to use wasted energy from the bike like using braking to charge the battery, but we don't do that for reasons too.

there's a thought, I remember sidewall dynamos decelerating a bike very usefully on a very steep downhill here, if there were a remote way to engage and disengage a sidewall dynamo it could save a lot of brake wear..

 

[VictoryV]

there's a thought, I remember sidewall dynamos decelerating a bike very usefully on a very steep downhill here, if there were a remote way to engage and disengage a sidewall dynamo it could save a lot of brake wear..

brake pads are cheaper than tyre sidewalls, and easier to change too

 

[flecc]

brake pads are cheaper than tyre sidewalls, and easier to change too

But that's not how they wear. When hard and soft materials are in friction, it's the hard material that suffers the wear. I remember over sixty years ago when most of Britain commuted by bike and bottle dynamos were commonplace and used daily for a large part of the year, the serrations on dynamo wheels were often worn right down near to smooth. I never knew of a single incidence of tyre wall wear ending life before the tread was finished.
.

 

[neptune]

I remember people "fixing" a worn out dynamo pulley by fitting a rubber ring from a pop bottle stopper over it. It worked OK until it rained.

 

[selrahc1992]

I remember people "fixing" a worn out dynamo pulley by fitting a rubber ring from a pop bottle stopper over it. It worked OK until it rained.

as a somewhat tangent - look athe pics on this guy's blog - especially the teardrop fender design, so art deco/fifties/elegant its enough to make one want a dynamo light http://minisystem.blogspot.co.uk/

 

[Gubbins]

Perhaps a thought here ....
I think the most important thing first and foremost when riding at night is to be seen! Surely lighting is the last thing that should messed about with, after all, a dynamo or other electricity generating device wont stop you joining the flies that are splatted on someone's bumper when it fails to generate enough light to be noticed.
I have a pair of hope visions and 2 spare battery cages with 4 AA 2900 rechargeable batteries in each. Not the cheapest way but It takes about 15 seconds to slip one cage out and another in, with at least 3 hours run time on full, thats 12 hours for 1 lamp or 6 hours for two.. easily recharged and they never both run out together so I feel visible and safe ish when out..

 

[VictoryV]

But that's not how they wear. When hard and soft materials are in friction, it's the hard material that suffers the wear. I remember over sixty years ago when most of Britain commuted by bike and bottle dynamos were commonplace and used daily for a large part of the year, the serrations on dynamo wheels were often worn right down near to smooth. I never knew of a single incidence of tyre wall wear ending life before the tread was finished.
.

I stand corrected (as usual), however are modern tyres built with the heavy serrated sidewalls that my "Dunlop Roadsters" (think that was their name 26" x 1 7/8") used to have to withstand the effect of a dynamo wheel rubbing on them

 

[flecc]

I stand corrected (as usual), however are modern tyres built with the heavy serrated sidewalls that my "Dunlop Roadsters" (think that was their name 26" x 1 7/8") used to have to withstand the effect of a dynamo wheel rubbing on them

Yes they have them still, not surprising since today's better cycle lighting firms still make bottle dynamos. I had a pair of Maxxis tyre on a bottle dynamo e-bike which were branded as "For Electric Bike" on the sidewalls, and they had the serrated sidewalls. Both my eZee bikes had Kendas with serrations on the tyre sidewalls and so do the Schwalbe tyres they have fitted now:

 

[Alan Quay]

Perhaps a thought here ....l:

I think logic has long since been abandoned in this thread.

For under a tenner you could have TWO sets of battery lights that'll get you seen. For another tenner you could have a Cree torch that'll light the road for 100m. If you want to spend £30 all in you will be visible from the great wall of China.

Batteries: They make bikes better.

 

[JohnCade]

Like lowranger I have a Kalkhoff with the Shimano dynamo front hub. There is no discernible drag either with the light on or off and in the context of the power from the motor the slight drag which must exist is meaningless. Unlike the old bottle dynamos which had noticeable drag. Some cheap bikes without dynamos in the wheels have more bearing drag in my experience. The light is very good too and it also powers the backlight which has a brake light part that gets brighter when you slow. As well as the capacitor which keeps the lights on for a little bit when stopped. It's a requirement that there has to be a secondary light source in Germany I understand and batteries can get flat.

Personally I don't want to faff around with batteries in lights. Though I have a flashing back light powered by battery too. But the Shimano dynamo is great and I just leave the lights on all the time to be seen as I do in the car, and as I did when I rode a motorcycle.

 

[flecc]

Like lowranger I have a Kalkhoff with the Shimano dynamo front hub. There is no discernible drag either with the light on or off and in the context of the power from the motor the slight drag which must exist is meaningless. Unlike the old bottle dynamos which had noticeable drag.

My experiences too, the Shimano hubdynos having no discernable drag. In contrast the bottle dynamo on the Lafree Lite e-bike that I owned and shown below had a suprising amount of drag, engaging it was actually worse than having a two wheeled trailer attached on the flat:

 

[Deleted member 4366]

The hub dynamos have more drag than you think. The only way to see it is with the test I suggested above. So far, the only test result we have spinning the wheel is 6 seconds, which is very short. A direct drive motor will spin for longer than that. A dragless wheel shouldgo for about 2 minutes.