Dynamo...

[flecc]

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.

I agree they have drag as John has also said. However, like him I can't perceive it in isolation when cycling with the Shimano one, bikes with it riding like a bike without one. Only a comparative test like the one you indicate shows up the drag that's there.
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[grldtnr]

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.

Personally I am in favour of dyno lights, specially modern dyno hubs.
I used to run a lead acid battery system for a cat eye halogen spot light on the handlebar ,the 12v cells sat in the bottle cage ,there was a cable that plug into the lamp housing much like a phono lead from a hi-fi system,maybe the OP could do the same for his room requirements.
When I had a Sanyo dyno which mounted behind the bbkt, you could remotely engage it by means of a friction lever and cable mounted on the seat tube, best to stop before doing that otherwise the power surge would burn out the bulbs.
There very rarely nothing new in developments regards to bikes,old ideas are revisted time and again, only advanced materials make things better.

 

[tillson]

It's interesting that Kalkhoff started off using Dynamo lights around 2007 with the Agattu. Later, they changed to powering the lights from the battery, and now they seem to have reverted to a dynamo again on some of their latest models.

I wonder why they have done this. Personally, I think it makes more sense to power the lights from the bike battery.

 

[RobF]

I have an Alfine dynamo on the Rose.

There is no discernible drag when pedalling.

Decent lights, as others have said, so all-in-all a good piece of kit.

Except - this is an internet forum so there has to be an except - it's fiddle to disconnect the dynamo when you need to remove the front wheel.

Forget, and you will rip the wires from the back of the plug.

I believe some hub dynamos now have a form of connection which doesn't rely on a plug, so even that drawback has been sorted.

 

[VictoryV]

I have an Alfine dynamo on the Rose.

There is no discernible drag when pedalling.

Decent lights, as others have said, so all-in-all a good piece of kit.

Except - this is an internet forum so there has to be an except - it's fiddle to disconnect the dynamo when you need to remove the front wheel.

Forget, and you will rip the wires from the back of the plug.

I believe some hub dynamos now have a form of connection which doesn't rely on a plug, so even that drawback has been sorted.

my wife's 1970 raleigh shopper had two screw terminals on an insulated plate on the side of the front dynamo, one for the "live" and one for the "earth return" via the frame so the alternative has been around for ages

 

[RobF]

my wife's 1970 raleigh shopper had two screw terminals on an insulated plate on the side of the front dynamo, one for the "live" and one for the "earth return" via the frame so the alternative has been around for ages

I don't quite grasp that, but is the point there were no wires to disconnect for wheel removal?

 

[JamesC]

It's interesting that Kalkhoff started off using Dynamo lights around 2007 with the Agattu. Later, they changed to powering the lights from the battery, and now they seem to have reverted to a dynamo again on some of their latest models.

I wonder why they have done this. Personally, I think it makes more sense to power the lights from the bike battery.

As far as I can tell, the decision to fit a dynamo to an e-bike has (or maybe had) a lot to do with the classification of the e-bike under German law.

E-bikes assisted up to 25 km/h had to comply with the laws for bicycles which required the lights to be powered from a dynamo.

"Fast" E-bikes up to 45 km/h were considered as road vehicles and could therefore power their lights from the e-bike battery.

This link takes you to the Busch & Muller download page. If you look at Page 7 of their 2013 catalogue, they describe the requirements for e-bikes up to 2013.

Maybe the law has changed very recently to allow battery powered lights on bicycles.

James

 

[tillson]

Thanks for that link. The 2015 catalogue now states that all eBikes (in Germany) can utilise the battery to power the lights. Not just the S Pedelecs.

 

[flecc]

It's interesting that Kalkhoff started off using Dynamo lights around 2007 with the Agattu. Later, they changed to powering the lights from the battery, and now they seem to have reverted to a dynamo again on some of their latest models.

I wonder why they have done this. Personally, I think it makes more sense to power the lights from the bike battery.

Those particular battery-lit models used the Panasonic unit with voltage dropping by uneven chopping for it's integral low voltage lighting supply, which could only be used with tungsten filament bulbs, not with LEDs. Of course LEDs are far better than filament bulbs in many ways, though they can of course be powered from the bike's battery using a more conventional method.
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[VictoryV]

I don't quite grasp that, but is the point there were no wires to disconnect for wheel removal?

the wires were there, but undoing two small brass nuts to release the wires and their cable tags was very easy without any possibility of damage to the wiring setup.

 

[grldtnr]

the wires were there, but undoing two small brass nuts to release the wires and their cable tags was very easy without any possibility of damage to the wiring setup.

Like ' I wot I wrote earlier ',nothing new in bicycle tech,re dyno wiring

 

[JamesW]

Ok...
Just back from a week of working away.
I seem to have caused about as much controversy as suggesting putting swords on the hub centres to slice through cars that pass too close might have been expected to. Thank you all for all of you inputs and suggestions. I will think about this and decide what to do in time.

 

[RobF]

Like ' I wot I wrote earlier ',nothing new in bicycle tech,re dyno wiring

Yes and no.

Some of the latest dynos don't require anything to be undone to remove the wheel, other than the quick release skewer.

 

[Kenny]

Finally the temperature has crept up enough to try out my Busch and Muller Cyo Premium 80Lux dynamo light.
I also took along my Exposure Strada battery light (600Lumins) for comparison.

I headed out of town for a 10mile circuit of completely unlit single track road. I was quite impressed with the first couple of miles which was uphill at about 8 to 14mph.
The road seemed well lit but as the road leveled and my speed increased I wasn't so impressed.

I swapped over to the Exposure light and although it had a slightly brighter and more even beam it still made for a slightly uneasy ride especially when the rain came on (not good when you wear glasses).

For the downhill 1.5mile part of the ride which is twisty but with some 30mph straights I used both lights together which lit up the road very well.

So to summarize, for me a £50 - £80 dynamo light is probably fine for occasional use if you take it easy but for regular use I'd want something brighter.

There are brighter dynamo ones available that might be up to it (Supernova E3 triple and Exposure Revo) but both are around £160, plus you have to add the cost of a good Dynamo Hub .