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  #121  
Old March 14th 17, 08:10 PM posted to rec.bicycles.tech
James[_8_]
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On 15/03/17 01:41, Joerg wrote:
On 2017-03-13 17:19, Sir Ridesalot wrote:
On Monday, March 13, 2017 at 2:09:05 PM UTC-4, Joerg wrote:
On 2017-03-12 15:21, James wrote:
On 13/03/17 01:57, Joerg wrote:
On 2017-03-11 16:28, Sir Ridesalot wrote:


You need to look again at more modern stuff because many dynamo
hub standlights are quite bright for the time they stay on usually
a ferw minutes or so if needed. But then again absolutely NOTHING
ever works for you off the shelf.


Wrong, it does and I have written about it here in the NG. I bought
a Cree XM-L based light each for the road bike and the MTB. Of
course, since almost nothing in the world of cycling is very robust
or complete this had to be spiced up. Both lights got diffusor lenses
because they will otherwise blind others and the light distribution
wasn't to my liking. Big deal, you just buy diffusor lenses and
install them. Then the battery holders are lousy. This took a little
more work but nothing that can't be done with a trip to the hardware
store and basic hand tools:

http://www.analogconsultants.com/ng/bike/Battbox2.JPG


You just proved Sir's point. Well done Joerg.


Huh? I made it quite clear that my solution works. It does very well.

--
Regards, Joerg

http://www.analogconsultants.com/


Because NOTHING works for you umn.ess you modify it.


Not true. As I said before the lights on the MTB and the road bike are
standard off the shelf. The diffusor lenses I installed were also off
the shelf. Swapping the plain plastic against those is not something
that qualifies as "work" because it merely involved screwing off a ring
and then screwing that back on. Like putting relish on a sausage which
doesn't alter the sausage.

The new WTB saddle is also unmodified. And the panniers. And the
speedometers. And ...

Yes, a lot of cycling gear is designed wrong or built in an inferior
quality but not everything. Therefore, your statement "absolutely
NOTHING" is not correct :-)


"Then the battery holders are lousy. This took a little more work but
nothing that can't be done with a trip to the hardware store and basic
hand tools:"

Huh? Indeed.

--
JS
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  #122  
Old March 14th 17, 08:12 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 3,400
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On 2017-03-14 13:10, James wrote:
On 15/03/17 01:41, Joerg wrote:
On 2017-03-13 17:19, Sir Ridesalot wrote:
On Monday, March 13, 2017 at 2:09:05 PM UTC-4, Joerg wrote:
On 2017-03-12 15:21, James wrote:
On 13/03/17 01:57, Joerg wrote:
On 2017-03-11 16:28, Sir Ridesalot wrote:


You need to look again at more modern stuff because many dynamo
hub standlights are quite bright for the time they stay on usually
a ferw minutes or so if needed. But then again absolutely NOTHING
ever works for you off the shelf.


Wrong, it does and I have written about it here in the NG. I bought
a Cree XM-L based light each for the road bike and the MTB. Of
course, since almost nothing in the world of cycling is very robust
or complete this had to be spiced up. Both lights got diffusor lenses
because they will otherwise blind others and the light distribution
wasn't to my liking. Big deal, you just buy diffusor lenses and
install them. Then the battery holders are lousy. This took a little
more work but nothing that can't be done with a trip to the hardware
store and basic hand tools:

http://www.analogconsultants.com/ng/bike/Battbox2.JPG


You just proved Sir's point. Well done Joerg.


Huh? I made it quite clear that my solution works. It does very well.

--
Regards, Joerg

http://www.analogconsultants.com/

Because NOTHING works for you umn.ess you modify it.


Not true. As I said before the lights on the MTB and the road bike are
standard off the shelf. The diffusor lenses I installed were also off
the shelf. Swapping the plain plastic against those is not something
that qualifies as "work" because it merely involved screwing off a ring
and then screwing that back on. Like putting relish on a sausage which
doesn't alter the sausage.

The new WTB saddle is also unmodified. And the panniers. And the
speedometers. And ...

Yes, a lot of cycling gear is designed wrong or built in an inferior
quality but not everything. Therefore, your statement "absolutely
NOTHING" is not correct :-)


"Then the battery holders are lousy. This took a little more work but
nothing that can't be done with a trip to the hardware store and basic
hand tools:"

Huh? Indeed.


Read the above again. There are lamps and then there are batteries and
then there are battery holders. Very different things.

Yes, a large chunk of bicycle accessories is flimsy and unfit for
serious use but some is fit as-is.

--
Regards, Joerg

http://www.analogconsultants.com/
  #123  
Old March 15th 17, 12:29 AM posted to rec.bicycles.tech
SMS
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On 3/13/2017 5:58 PM, Doug Landau wrote:

So he's a tweak snob. I point my saddle 1 degree to the right 'cuz my left nut is bigger.


Wow, were you using a digital vernier caliper to measure that?

  #124  
Old March 15th 17, 12:42 AM posted to rec.bicycles.tech
Doug Landau
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On Tuesday, March 14, 2017 at 5:32:39 PM UTC-7, sms wrote:
On 3/13/2017 5:58 PM, Doug Landau wrote:

So he's a tweak snob. I point my saddle 1 degree to the right 'cuz my left nut is bigger.


Wow, were you using a digital vernier caliper to measure that?


LOL Naw I knew that from years of playing with myself


  #125  
Old March 15th 17, 12:57 AM posted to rec.bicycles.tech
SMS
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Posts: 7,725
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On 3/13/2017 7:49 PM, jbeattie wrote:
On Monday, March 13, 2017 at 5:36:49 PM UTC-7, Frank Krygowski wrote:
On 3/13/2017 4:08 PM, sms wrote:
On 3/13/2017 12:50 PM, Joerg wrote:
On 2017-03-13 12:19, Frank Krygowski wrote:
On 3/13/2017 2:06 PM, Joerg wrote:

Then you'd be back to this inferior dynamo lighting which goes out at
the traffic light, or uses dimmed or short-lived light if there is a
supercap installed.

Where are the tragic tales of cyclists who are seriously injured or
killed because their dynamo standlights were too dim or too short-lived?
Somehow those tales have failed to make it into the safety literature!


As we all know reports of fatal car-cyclist collisions are notoriously
short on details.

You claim to be something like a "teacher for safe cycling" yet you
don't know or ignore the most basic safety precautions. Astounding.
Actually, sad.

Unless their is a case-controlled, double-blind, study, Frank won't
believe that increasing visibility at night, both for seeing and being
seen, is beneficial.


Oh, come on, Stephen. People getting hit because their standlights are
too dim? We don't even have anecdotes about that!


As close as I can get to an anecdote is the guy I saw a night or two ago here in SLC who was mostly invisible until his dyno light lit up. It didn't have any stand light. He was turning across traffic, and I didn't hit him -- but a little more warning would have been nice.


As a cyclists, I suspect that you do take more care in looking for
cyclists that are not legally lit.

  #126  
Old March 15th 17, 01:35 AM posted to rec.bicycles.tech
Jeff Liebermann
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Posts: 2,265
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On Tue, 14 Mar 2017 10:46:19 -0400, Frank Krygowski
wrote:

On 3/13/2017 11:00 PM, Jeff Liebermann wrote:
I was thinking of building a benchtop dynamometer sized for bicycle
lighting. I don't have the equipment to calibrate it so I could
measure overall efficiency, but certainly can make comparative
measurements of the input power(s) required to light an oversized load
or bulb. Basically, just a DC motor with a DC wattmeter on the power
leads.
http://www.ebay.com/itm/122373782338
(Yet another project that I'll never finish).


What are you intending to measure? Input power to a bike dynamo?


Ideally, overall efficiency of the lighting system and verification of
the simulation and dynamo model.

Mechanical power (watts) in, as simulated by an electric motor vs
optical power out, measured in lumens or lux. The main exercise would
be calibrating the major components so that the measurements would be
accurate and meaningful. It would be something like the
Friction-Facts chain and lubricant test fixture in:
http://www.friction-facts.com/equipment-overview
Oh swell, all the links are broken. 2nd best:
http://www.bikeradar.com/news/article/friction-facts-measuring-drivetrain-efficiency-35694/
or something like this:
http://pages.jh.edu/news_info/news/home99/aug99/bike.html
but with the gearing replaced by a dynamo.

I vaguely recall a Friction-Facts web page mumbling something about
calibrated motors and generators being rather expensive.

Initially, the simulation part didn't seem too difficult. Just some
non-linear parts, such as core saturation and LED light output, needed
to be accommodated. I added kinematics model, so that changes in
wheel diameters and gearing could be shown. Well, after entering
idealized versions of all the possible formulas and parameters into a
spreadsheet to estimate the complexity, I decided that building a
dynamometer was far too messy for my available time, work area, and
abilities.



--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #127  
Old March 15th 17, 02:43 AM posted to rec.bicycles.tech
Jeff Liebermann
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On Tue, 14 Mar 2017 07:54:26 -0700, Joerg
wrote:

On 2017-03-13 20:00, Jeff Liebermann wrote:
On Mon, 13 Mar 2017 12:38:07 -0700, Joerg
wrote:
55V at 500mA. This is encouraging.


That's 27.5 watts out of a 3 watt dynamo. I was impressed, until I
converted 136 km/hr and found that it was 84.5 mph. With a rocket
assisted bicycle, I might be able to do that.


Well, yeah, they just wanted to see where the limit is. I guess the
enameled copper wire inside would smoke out if you kept that speed for long.


Only the resistive part dissipates power in the wi
P = I^2 * R = 0.5^2 * 2 = 0.5 watts
So, it won't be the wire that gets hot. However, the cores in
saturation are going to get warm. Offhand, I don't know how to
calculate how hot.

However, this means I should be comfortably able to milk 10W or more out
of such a dynamo on a long downhill stretch and maybe north of 5W during
regular rides on flat terrain. IOW there seems to be nothing that
inherently limits things to the usual measly 3-4W.


Maybe. Let's pretend that the test demonstrates that the dynamo can
deliver 28 watts for perhaps 60 minutes before blowing up. Assuming
constant energy (Joules or watt-seconds) at any speed. That would be
10 watts for 168 minutes. Assuming 10 watts output is a comfortable
ride for you, you would have about 3 hrs of bright light before the
dynamo self-destructed. Actually, it would probably be more like 4 or
5 hrs since the system is not adiabatic and the heat radiation
efficiency of the dynamo case is time dependent.

The author is mostly correct about hubs not going into saturation as
easily and bottle dynamos. However, they do go into staturation, just
at a higher RPM.


If that happens above 84mph I shall be happy :-)


Dream on. If you look at the dynamo speed vs power curves at:
http://www.myra-simon.com/bike/dynotest.html
They all begin to go into saturation at 15 to 20 km/hr. At 136 km/hr,
the dynamo will produce 27.5 watts, but the rest of the input energy
will be wasted in core saturation heating. If you paint flames on the
fenders, maybe other riders will think the burning dynamo is normal.

http://www.ebay.com/itm/122373782338
(Yet another project that I'll never finish).


That is a neat little instrument.


Yep. I don't have one yet, but it's a real temptation to install one
on all my various unmetered power supplies and battery packs. However,
there's a catch. The common ground is positive (+), not negative.
You can see that in the schematic:
https://img.alicdn.com/imgextra/i3/121163002/TB2NoBogpXXXXahXpXXXXXXXXXX_!!121163002.jpg
where the + leads of both the "DC in" and the load are connected
together. The only ways I could make it work in a negative ground
system was either an isolated power source, isolated load, separate
isolated power supply to run the meter, or a DC-DC inverter.

Anyhow, I don't
think a dynamo can easily be simulated until you start with a mechanical
model of it and that gets into COMSOL and other really expensive
modeling software. Maybe possible with MathCad which I have but rarely
use so I became rusty there.


Yep. That was pretty much my conclusion. Jim Thomson posted this
Pspice component model:
https://groups.google.com/forum/#!topic/sci.electronics.design/yPVvclIIirQ
which I have been unable to convert to LTSpice. He seems to just put
a sharp knee where the dynamo starts to go into saturation. That's
probably good enough to get started. The rest is mechanical and
rather messy if I add nonlinearities, friction, and air resistance. I
do have one advantage with a hub dynamo. I can characterize it as a
motor on the bench and then simply invert the derived functions to
produce a generator. That might be a worthy shortcut.


--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #128  
Old March 15th 17, 02:57 AM posted to rec.bicycles.tech
Jeff Liebermann
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On Mon, 13 Mar 2017 15:19:22 -0400, Frank Krygowski
wrote:

On 3/13/2017 2:06 PM, Joerg wrote:

Then you'd be back to this inferior dynamo lighting which goes out at
the traffic light, or uses dimmed or short-lived light if there is a
supercap installed.


Where are the tragic tales of cyclists who are seriously injured or
killed because their dynamo standlights were too dim or too short-lived?
Somehow those tales have failed to make it into the safety literature!


There are no such tales because a cyclist that is not in motion could
be considered a pedestrian.

"Pedestrian Deaths Make Up a Rising Share of U.S. Traffic Fatalities"
http://usa.streetsblog.org/2016/03/09/pedestrian-deaths-make-up-a-rising-share-of-u-s-traffic-fatalities/
"In a typical year, nearly 5,000 Americans are killed while
walking".
I wonder how many of those were actually cyclists walking their
bicycles or waiting at a stop sign or signal (with or without a stand
light)?



--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #129  
Old March 15th 17, 03:15 AM posted to rec.bicycles.tech
Jeff Liebermann
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Posts: 2,265
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On Tue, 14 Mar 2017 12:09:27 -0400, Frank Krygowski
wrote:
But the point I was discussing was whether too brief or too dim
standlights really kill or seriously injure _stationary_ bicyclists.
I've never heard of such a case. I think it's yet another exaggerated
danger.


Bicycle lighting seems to be divided into "see where your going" and
"be seen" parts. Standlights are in the "be seen" part. If so, then
using a relatively narrow forward facing headlight is inadequate and a
poor substitute for all around "be seen" type lighting.

So far, no driver has tried to kill me while I'm stationary, but it's
possible. To help prevent such a threat, I would need all around
illumination because I don't know from what direction the driver might
approach and I do NOT need to see where I'm going (because I'm not
going anywhere). Some kind of flashing headband, flashing arm bands,
or maybe downward facing flood lights to illuminate an area. Maybe an
LED illuminated vest, which is now popular among highway workers:
https://www.amazon.com/HIGH-VISIBILITY-VEST-COMPLIANT-REFLECTIVE/dp/B01L2US0EY
https://www.amazon.com/SE-EP08L-Illuminated-Flashing-Feature/dp/B008WAE2XQ
https://www.amazon.com/SE-EP07L-Flashing-Illuminated-Safety/dp/B004J663A2
I don't know which type of "be seen" lighting might be most effective,
but any of the aformentioned would be better than a dim forward facing
standlight.




--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #130  
Old March 15th 17, 04:14 AM posted to rec.bicycles.tech
James[_8_]
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Posts: 5,513
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On 15/03/17 13:43, Jeff Liebermann wrote:
On Tue, 14 Mar 2017 07:54:26 -0700, Joerg
wrote:

On 2017-03-13 20:00, Jeff Liebermann wrote:
On Mon, 13 Mar 2017 12:38:07 -0700, Joerg
wrote:
55V at 500mA. This is encouraging.


That's 27.5 watts out of a 3 watt dynamo. I was impressed, until I
converted 136 km/hr and found that it was 84.5 mph. With a rocket
assisted bicycle, I might be able to do that.


Well, yeah, they just wanted to see where the limit is. I guess the
enameled copper wire inside would smoke out if you kept that speed for long.


Only the resistive part dissipates power in the wi
P = I^2 * R = 0.5^2 * 2 = 0.5 watts
So, it won't be the wire that gets hot. However, the cores in
saturation are going to get warm. Offhand, I don't know how to
calculate how hot.


Do you mean eddy currents in the core?

--
JS
 




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