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#1
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Is there an updated Dynotest somewhere?
Many years ago a fairly quantitative report on the performance of
bicycle lighting dynamos was published on the Web. The link is http://www.myra-simon.com/bike/dynotest.html Most of the brands named are long gone. Is there a more modern report of similar quality to be found? I've looked and found nothing remotely quantitative, just a lot of exuberant descriptions. There seem to be a considerable number of new (mostly hub) dynamos, hopefully somebody has measured what they can do. Thanks for reading, and any guidance, bob prohaska |
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#2
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Is there an updated Dynotest somewhere?
bob prohaska wrote:
Many years ago a fairly quantitative report on the performance of bicycle lighting dynamos was published on the Web. The link is http://www.myra-simon.com/bike/dynotest.html Most of the brands named are long gone. Is there a more modern report of similar quality to be found? I've looked and found nothing remotely quantitative, just a lot of exuberant descriptions. There seem to be a considerable number of new (mostly hub) dynamos, hopefully somebody has measured what they can do. As the more recent tests were mostly conducted "by SON's Andreas Oehler or one of his buddies," they have not met r.b.t's stringent anti-corruption criteria: https://www.cyclingabout.com/dynamo-hub-drag-lab-testing/ (is a translation of https://fahrradzukunft.de/14/neue-nabendynamos-im-test/ Some things that have changed since the dynotest age: - bottle dynamo market has mostly bifurcated into "cheap replacement" and "pointless hipster specialty" items https://fahrradzukunft.de/18/labortest-felgenlaeuferdynamos/ - more (bottle) dynamos feature inbuilt hard voltage limitation, potentially limiting light output - new, low-power "1.5W" generator category, marketed at dragophobes subjective advice: Shimano generators have improved. For their 3 Watt hubs, stay away from anything even more basic than their, from old to new, DH-3N30, DH-3N31, DH-C3000 hub lines. Get (import) an identical pair of low-to midrange Shimano hubs, and in case of failure, beat SON's (or Taiwan's) service turnaround time hands-down by locally rebuilding the wheel. |
#3
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Is there an updated Dynotest somewhere?
On 9/9/2017 4:24 AM, Sepp Ruf wrote:
bob prohaska wrote: Many years ago a fairly quantitative report on the performance of bicycle lighting dynamos was published on the Web. The link is http://www.myra-simon.com/bike/dynotest.html Most of the brands named are long gone. Is there a more modern report of similar quality to be found? I've looked and found nothing remotely quantitative, just a lot of exuberant descriptions. There seem to be a considerable number of new (mostly hub) dynamos, hopefully somebody has measured what they can do. As the more recent tests were mostly conducted "by SON's Andreas Oehler or one of his buddies," they have not met r.b.t's stringent anti-corruption criteria: https://www.cyclingabout.com/dynamo-hub-drag-lab-testing/ (is a translation of https://fahrradzukunft.de/14/neue-nabendynamos-im-test/ Some things that have changed since the dynotest age: - bottle dynamo market has mostly bifurcated into "cheap replacement" and "pointless hipster specialty" items https://fahrradzukunft.de/18/labortest-felgenlaeuferdynamos/ - more (bottle) dynamos feature inbuilt hard voltage limitation, potentially limiting light output - new, low-power "1.5W" generator category, marketed at dragophobes subjective advice: Shimano generators have improved. For their 3 Watt hubs, stay away from anything even more basic than their, from old to new, DH-3N30, DH-3N31, DH-C3000 hub lines. Get (import) an identical pair of low-to midrange Shimano hubs, and in case of failure, beat SON's (or Taiwan's) service turnaround time hands-down by locally rebuilding the wheel. Good info from Sep Ruff (and I wish I read Deutsch). But Bob, can I ask what your objectives are? I ask because some of this may not matter much any more. Seems to me there was a time when it made sense to worry about which dynamos might put out a little more power, or which had a little less drag. But with modern LED dynamo lights from Busch & Muller, there is plenty of light available right where you need it; and almost any dyno can supply the power. You'll never notice the differences in drag between the various hub dynos. I agree that the Shimano DH-3N30 works perfectly well. The two bikes I ride most often at night have hub dynos. But on a couple bikes that I ride only occasionally at night, I've got old bottle dynamos or roller dynamos. They work very well and have the benefit of zero drag when off. Yet those bikes have good lights available whenever needed, with no battery worries. And a bottle or (if you're really lucky) a roller dynamo can be had for free these days. It's a benefit of being out of fashion. Their main disadvantage is trickier installation, requiring understanding their wiring and perhaps fabricating a bracket. But I can handle that. -- - Frank Krygowski |
#4
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Is there an updated Dynotest somewhere?
Frank Krygowski wrote:
Good info from Sep Ruff (and I wish I read Deutsch). But Bob, can I ask what your objectives are? Simply to make a well-informed choice. Hub dynamos represent a lot of money when a wheel is laced on them, a Schmidt is expensive even before that. It would be nice to know what I'm getting before paying for it. The application is daytime running lights. I ask because some of this may not matter much any more. Seems to me there was a time when it made sense to worry about which dynamos might put out a little more power, or which had a little less drag. But with modern LED dynamo lights from Busch & Muller, there is plenty of light available right where you need it; and almost any dyno can supply the power. You'll never notice the differences in drag between the various hub dynos. Yes, lights are better, but the materials available to dynamo builders are better also, and I have (possibly misguided) hopes that somebody, somewhere, is exploiting them. Rare earth magnets are one improvement, use of laminated armature poles would be another. Together they might be worth a factor of two, redeemable either in efficiency or weight. I agree that the Shimano DH-3N30 works perfectly well. The two bikes I ride most often at night have hub dynos. But on a couple bikes that I ride only occasionally at night, I've got old bottle dynamos or roller dynamos. They work very well and have the benefit of zero drag when off. Yet those bikes have good lights available whenever needed, with no battery worries. I've got a Breezer with a DH-3N30 hub dynamo and have worn out a couple of Union rollers on my Cannondale. Neither type seems decisively better, and neither is impressive. The Shimano is huge and heavy, the Unions were noisy and prone to bouncing if anything stuck to the roller. And a bottle or (if you're really lucky) a roller dynamo can be had for free these days. It's a benefit of being out of fashion. Their main disadvantage is trickier installation, requiring understanding their wiring and perhaps fabricating a bracket. But I can handle that. As can I. At this stage I'd like something better and am looking for guidance as to what (if anything) is better. Thanks for reading! bob prohaska |
#5
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Is there an updated Dynotest somewhere?
Sepp Ruf wrote:
As the more recent tests were mostly conducted "by SON's Andreas Oehler or one of his buddies," they have not met r.b.t's stringent anti-corruption criteria: https://www.cyclingabout.com/dynamo-hub-drag-lab-testing/ (is a translation of https://fahrradzukunft.de/14/neue-nabendynamos-im-test/ That article actually comes somewhat close to what I was looking for. The real disappointment is the photo: It shows a (very expensive) Schmidt hub containing a clawpole armature. That is somewhat borne out in the efficiency. It's only around 50%. Seems to me Schmidt has considerable room for improvement. Even the cheapest electric machines use laminated armatures. If that represents the state of the hub dynamo art it's in a bad way. They're obviously aware of eddy current losses (note the notch in the visible pole piece) but the losses extend to the entire volume of magnetic material. It's as if they're unaware of the skin effect. Some things that have changed since the dynotest age: - bottle dynamo market has mostly bifurcated into "cheap replacement" and "pointless hipster specialty" items https://fahrradzukunft.de/18/labortest-felgenlaeuferdynamos/ - more (bottle) dynamos feature inbuilt hard voltage limitation, potentially limiting light output - new, low-power "1.5W" generator category, marketed at dragophobes subjective advice: Shimano generators have improved. For their 3 Watt hubs, stay away from anything even more basic than their, from old to new, DH-3N30, DH-3N31, DH-C3000 hub lines. Get (import) an identical pair of low-to midrange Shimano hubs, and in case of failure, beat SON's (or Taiwan's) service turnaround time hands-down by locally rebuilding the wheel. For the moment I think I'll try to revive my old Soubitez roller dynamo and hope somebody gets past the 19th century. Thanks for posting! bob prohaska |
#6
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Is there an updated Dynotest somewhere?
On 09/09/17 18:24, Sepp Ruf wrote:
bob prohaska wrote: Many years ago a fairly quantitative report on the performance of bicycle lighting dynamos was published on the Web. The link is http://www.myra-simon.com/bike/dynotest.html Most of the brands named are long gone. Is there a more modern report of similar quality to be found? I've looked and found nothing remotely quantitative, just a lot of exuberant descriptions. There seem to be a considerable number of new (mostly hub) dynamos, hopefully somebody has measured what they can do. As the more recent tests were mostly conducted "by SON's Andreas Oehler or one of his buddies," they have not met r.b.t's stringent anti-corruption criteria: https://www.cyclingabout.com/dynamo-hub-drag-lab-testing/ (is a translation of https://fahrradzukunft.de/14/neue-nabendynamos-im-test/ Some things that have changed since the dynotest age: - bottle dynamo market has mostly bifurcated into "cheap replacement" and "pointless hipster specialty" items https://fahrradzukunft.de/18/labortest-felgenlaeuferdynamos/ - more (bottle) dynamos feature inbuilt hard voltage limitation, potentially limiting light output - new, low-power "1.5W" generator category, marketed at dragophobes subjective advice: Shimano generators have improved. For their 3 Watt hubs, stay away from anything even more basic than their, from old to new, DH-3N30, DH-3N31, DH-C3000 hub lines. Get (import) an identical pair of low-to midrange Shimano hubs, and in case of failure, beat SON's (or Taiwan's) service turnaround time hands-down by locally rebuilding the wheel. My SP PV8 hub dynamo has been in service for a few years now. I guess that means it's done near 30,000km already, with no issues to report. Characteristics very similar to a SON, but without the price tag, -- JS |
#7
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Is there an updated Dynotest somewhere?
On 10/09/17 15:24, bob prohaska wrote:
Sepp Ruf wrote: As the more recent tests were mostly conducted "by SON's Andreas Oehler or one of his buddies," they have not met r.b.t's stringent anti-corruption criteria: https://www.cyclingabout.com/dynamo-hub-drag-lab-testing/ (is a translation of https://fahrradzukunft.de/14/neue-nabendynamos-im-test/ That article actually comes somewhat close to what I was looking for. The real disappointment is the photo: It shows a (very expensive) Schmidt hub containing a clawpole armature. That is somewhat borne out in the efficiency. It's only around 50%. Seems to me Schmidt has considerable room for improvement. Even the cheapest electric machines use laminated armatures. If that represents the state of the hub dynamo art it's in a bad way. They're obviously aware of eddy current losses (note the notch in the visible pole piece) but the losses extend to the entire volume of magnetic material. It's as if they're unaware of the skin effect. For the moment I think I'll try to revive my old Soubitez roller dynamo and hope somebody gets past the 19th century. Notice the laminated magnetic material in the SP dynamo hub. https://janheine.files.wordpress.com/2012/09/pv8.jpg -- JS |
#8
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Is there an updated Dynotest somewhere?
On 9/10/2017 4:49 PM, James wrote:
snip My SP PV8 hub dynamo has been in service for a few years now.* I guess that means it's done near 30,000km already, with no issues to report. Characteristics very similar to a SON, but without the price tag, SP claims that its tests show higher efficiency than the SON. I guess that's as valid a conclusion as the tests published by SON. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
#9
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Is there an updated Dynotest somewhere?
sms wrote:
On 9/10/2017 4:49 PM, James wrote: snip My SP PV8 hub dynamo has been in service for a few years now.? I guess that means it's done near 30,000km already, with no issues to report. Characteristics very similar to a SON, but without the price tag, SP claims that its tests show higher efficiency than the SON. I guess that's as valid a conclusion as the tests published by SON. SP is something of a puzzle. They used a laminated armature, but it's still a clawpole design. I'd be curious to know their reasoning. From where I sit it looks too wrongheaded to be worth spending much money on, but if one came to hand it'd be worth exploring. It looks as if the cost is somewhere over 100 US$ Does SP have a US dealer? Thanks for posting! bob prohaska |
#10
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Is there an updated Dynotest somewhere?
James wrote:
On 09/09/17 18:24, Sepp Ruf wrote: bob prohaska wrote: Many years ago a fairly quantitative report on the performance of bicycle lighting dynamos was published on the Web. The link is http://www.myra-simon.com/bike/dynotest.html Most of the brands named are long gone. Is there a more modern report of similar quality to be found? I've looked and found nothing remotely quantitative, just a lot of exuberant descriptions. There seem to be a considerable number of new (mostly hub) dynamos, hopefully somebody has measured what they can do. As the more recent tests were mostly conducted "by SON's Andreas Oehler or one of his buddies," they have not met r.b.t's stringent anti-corruption criteria: https://www.cyclingabout.com/dynamo-hub-drag-lab-testing/ My SP PV8 hub dynamo has been in service for a few years now. I guess that means it's done near 30,000km already, with no issues to report. Good to hear, good for you! How many indoor/outdoor temperature cycles at 100% humidity, how much frost, road salt, Joerg-ific Wisconsin winters has it been exposed to? Characteristics very similar to a SON, but without the price tag, .... and without the virtue-signaling at taxpayer's (and their daughters') expense, I shall add. 5 year warranty, too? Admittedly, this has lost much appeal since SON updated the construction and the entire hub needs to be sent for service. |
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