Is there an updated Dynotest somewhere?
 

On 9/10/2017 7:55 PM, James wrote:
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

But it doesn't seem like it affected the efficiency very much. I think
we're chasing diminishing returns. The major point of the article at
https://www.cyclingabout.com/dynamo-...g-lab-testing/ is that the
drag is not much to worry about.

--
- Frank Krygowski

Is there an updated Dynotest somewhere?
 

Frank Krygowski wrote:
On 9/10/2017 7:55 PM, James wrote:
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

But it doesn't seem like it affected the efficiency very much. I think
we're chasing diminishing returns. The major point of the article at
https://www.cyclingabout.com/dynamo-...g-lab-testing/ is that the
drag is not much to worry about.

For Rob who might experience mental drag uphill from just having to see a
big, heavy, non-laminated hub slowly revolving in the front wheel, the
smallish Shimano DH-T780-1N, 1.5W 250mA class, might suffice[1] once he
grows sick of the Soubitez. Best price I see is 96 euros a pair from CNC
Hamburg on ebay, no overseas shipping available, though.
http://www.ebay.com/itm/253093811841

[1]
DRL does not require more than 100 lumens if you get the optics right.

Is there an updated Dynotest somewhere?
 

On Mon, 11 Sep 2017 21:24:10 -0400, Frank Krygowski
wrote:

On 9/10/2017 7:55 PM, James wrote:
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

But it doesn't seem like it affected the efficiency very much. I think
we're chasing diminishing returns. The major point of the article at
https://www.cyclingabout.com/dynamo-...g-lab-testing/ is that the
drag is not much to worry about.

I wonder whether size, output and cost may not enter into it. After
all one doesn't want a 10 inch hub and the things only puts out an
almost negligible amount of power. Some 2 - 3 watts was it? And cost
is usually mentioned in any review of hub generators.
--
Cheers,

John B.

Is there an updated Dynotest somewhere?
 

On 9/11/2017 11:59 PM, Sepp Ruf wrote:

snip

For Rob who might experience mental drag uphill from just having to see a
big, heavy, non-laminated hub slowly revolving in the front wheel, the
smallish Shimano DH-T780-1N, 1.5W 250mA class, might suffice[1] once he
grows sick of the Soubitez. Best price I see is 96 euros a pair from CNC
Hamburg on ebay, no overseas shipping available, though.
http://www.ebay.com/itm/253093811841

[1]
DRL does not require more than 100 lumens if you get the optics right.

True, but if you want a dynamo light for more than just a DRL then that
won't do.

I have an SP dynamo (relabeled as "Joule") on a 20" wheel on a Dahon.
It's coupled to a European dynamo light with about the best optics
available, but at a claimed 200 lumens it's still really only useful as
a DRL, plus it does not have a flash function.

The SP PV-8 claims 72% efficiency. SON claims 65%. I don't think either
company is going to spend much trying to improve that number given the
way the bicycle lighting market is going. Even at perfect efficiency
you;re not going to be able to run even a mid-range 1000 lumen light,
let alone the 2500+ lumen lights that bicycle commuters require.

I am going to Interbike next week and I'll see what new lighting
products are available. But Interbike is shrinking with a lot of
companies pulling out. Next year it's in Reno instead of Las Vegas, and
it will shrink even more since Reno is not as convenient and cheap to
get to, and in a few years it will go the way of Comdex.

Is there an updated Dynotest somewhere?
 

On 9/12/2017 3:50 AM, sms wrote:
On 9/11/2017 11:59 PM, Sepp Ruf wrote:

snip

For Rob who might experience mental drag uphill from just having to see a
big, heavy, non-laminated hub slowly revolving in the front wheel, the
smallish Shimano DH-T780-1N, 1.5W 250mA class, might suffice[1] once he
grows sick of the Soubitez.* Best price I see is 96 euros a pair from CNC
Hamburg on ebay, no overseas shipping available, though.
http://www.ebay.com/itm/253093811841

[1]
DRL does not require more than 100 lumens if you get the optics right.

True, but if you want a dynamo light for more than just a DRL then that
won't do.

I have an SP dynamo (relabeled as "Joule") on a 20" wheel on a Dahon.
It's coupled to a European dynamo light with about the best optics
available, but at a claimed 200 lumens it's still really only useful as
a DRL, plus it does not have a flash function.

I should add, that I've designed a hack to add modulated capability to
all these European-standard dynamo lights that lack it.

Since when dynamo power is cut off the standlight comes on at lower
brightness, by interrupting the AC power to the light you can modulate
the intensity. Using a magnetic reed switch with a wheel magnet is the
simplest solution but the flash rate varies with wheel speed. Using a
Triac with a timer is a better solution but it needs DC power for the
timer so it gets more complex.

If there were much of a market for dynamo lights in countries where
flashing DRLs are not illegal, then the manufacturers might consider
including modulated DRL functionality.

The only dynamo light I've seen with a DRL flash function is the Planet
Bike Blaze Dynamo SL, which has been improved slightly over the original
and is now rated at 150 lumens. Nashbar has it for $42.18 right now (26%
discount). Once you give up on the idea that ANY dynamo light is going
to be sufficient for commuting, and accept that it's only going to be
useful as a DRL, the Planet Bike light is a pretty good deal. But it
won't work with the 1.5W Shimano dynamo, it needs a 2.4-3.0W dynamo.

Is there an updated Dynotest somewhere?
 

On Sunday, September 10, 2017 at 4:56:00 PM UTC-7, James wrote:
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

Hm. Is that thing planing?

Is there an updated Dynotest somewhere?
 

On Tuesday, September 12, 2017 at 6:50:39 AM UTC-4, sms wrote:
On 9/11/2017 11:59 PM, Sepp Ruf wrote:

snip

For Rob who might experience mental drag uphill from just having to see a
big, heavy, non-laminated hub slowly revolving in the front wheel, the
smallish Shimano DH-T780-1N, 1.5W 250mA class, might suffice[1] once he
grows sick of the Soubitez. Best price I see is 96 euros a pair from CNC
Hamburg on ebay, no overseas shipping available, though.
http://www.ebay.com/itm/253093811841

[1]
DRL does not require more than 100 lumens if you get the optics right.

True, but if you want a dynamo light for more than just a DRL then that
won't do.

I have an SP dynamo (relabeled as "Joule") on a 20" wheel on a Dahon.
It's coupled to a European dynamo light with about the best optics
available, but at a claimed 200 lumens it's still really only useful as
a DRL, plus it does not have a flash function.

... Even at perfect efficiency you;re not going to be able to run even a
mid-range 1000 lumen light, let alone the 2500+ lumen lights that bicycle
commuters require.

Good grief. The "Danger! Danger!" crew is insanely into the lumen wars. After
many decades of millions of commuters doing perfectly well with 80 lumen
halogen bulbs, how is it suddenly "required" to have 2500 lumens?

BTW, I saw a new phenomenon yesterday. Driving along a two lane highway, I
saw a very bright flashing white light from about a mile back. I wondered
what sort of emergency vehicle or road work it might be.

Over a minute later, I passed a bike rider. She had an insanely bright bike
headlight mounted on the back of her bike, pointed back at traffic. As I
changed lanes to pass (which I would have done anyway) the thing was so
bright that it literally hurt my eyes.

It's illegal for a white light to be pointed rearward like that. But I'm sure
the rider felt that it was so dangerous to ride a bike that she should
violate that law, and also blind or inconvenience any other road users.

- Frank Krygowski

Is there an updated Dynotest somewhere?
 

On 12/09/17 12:50, sms wrote:
On 9/11/2017 11:59 PM, Sepp Ruf wrote:

snip

For Rob who might experience mental drag uphill from just having to see a
big, heavy, non-laminated hub slowly revolving in the front wheel, the
smallish Shimano DH-T780-1N, 1.5W 250mA class, might suffice[1] once he
grows sick of the Soubitez. Best price I see is 96 euros a pair from CNC
Hamburg on ebay, no overseas shipping available, though.
http://www.ebay.com/itm/253093811841

[1]
DRL does not require more than 100 lumens if you get the optics right.

True, but if you want a dynamo light for more than just a DRL then that
won't do.

I have an SP dynamo (relabeled as "Joule") on a 20" wheel on a Dahon.
It's coupled to a European dynamo light with about the best optics
available, but at a claimed 200 lumens it's still really only useful as
a DRL, plus it does not have a flash function.

What light is that?

snip

Is there an updated Dynotest somewhere?
 

On 12/09/17 21:39, Frank Krygowski wrote:

snip

It's illegal for a white light to be pointed rearward like that. But I'm sure
the rider felt that it was so dangerous to ride a bike that she should
violate that law, and also blind or inconvenience any other road users.

The safest course of action for a ton and a half of moving metal is to
blind it so it can't see where it's going. Well, tbh, the long term
safest thing...

Is there an updated Dynotest somewhere?
 

Tosspot wrote:

It's coupled to a European dynamo light

What light is that?

http://radtouren-magazin.com/wp-content/uploads/2017/02/Herrmans_hblackpro_9323.jpg
from
http://radtouren-magazin.com/11530/e-bike/test-e-bike-scheinwerfer

(Compared to the DC version shown in the test, the dynamo H-Black-Pro is
somewhat dimmer.) It doesn't really matter because the Herrmans optic is
annoyingly unrefined in either version. And, needless to say, it's a low
beam with a symmetrical cutoff, so it is certainly not producing a DRL beam
shape.