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Is there an updated Dynotest somewhere?



 
 
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  #1  
Old September 9th 17, 04:57 AM posted to rec.bicycles.tech
bob prohaska
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Posts: 26
Default 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  
Old September 9th 17, 09:24 AM posted to rec.bicycles.tech
Sepp Ruf
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Posts: 110
Default 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  
Old September 9th 17, 03:37 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 5,055
Default 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  
Old September 10th 17, 05:49 AM posted to rec.bicycles.tech
bob prohaska
external usenet poster
 
Posts: 26
Default 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  
Old September 10th 17, 06:24 AM posted to rec.bicycles.tech
bob prohaska
external usenet poster
 
Posts: 26
Default 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  
Old September 11th 17, 12:49 AM posted to rec.bicycles.tech
James[_8_]
external usenet poster
 
Posts: 5,625
Default 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  
Old September 11th 17, 12:55 AM posted to rec.bicycles.tech
James[_8_]
external usenet poster
 
Posts: 5,625
Default 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  
Old September 11th 17, 01:06 AM posted to rec.bicycles.tech
SMS
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Posts: 7,941
Default 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  
Old September 11th 17, 05:00 AM posted to rec.bicycles.tech
bob prohaska
external usenet poster
 
Posts: 26
Default 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  
Old September 11th 17, 10:40 AM posted to rec.bicycles.tech
Sepp Ruf
external usenet poster
 
Posts: 110
Default 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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