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  #91  
Old March 12th 17, 09:28 PM posted to rec.bicycles.tech
SMS
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On 3/11/2017 7:38 AM, Joerg wrote:
On 2017-03-10 19:40, Sir Ridesalot wrote:
On Friday, March 10, 2017 at 7:52:30 PM UTC-5, Joerg wrote: Snipped
With or without dynamo I'll never ride without a battery because
then it's lights out when waiting at an intersection. Very bad at
night.

Now, about the bicycle air conditioner ... :-)

-- Regards, Joerg

http://www.analogconsultants.com/


Most decent dynamo ights these days have a standlight that'll run for
several minutes when the bicycle is stopped.


I have seen that in Germany. Standlight was very dim though. I prefer it
to be lit normal like it is on my bikes.


On one of my dynamo lights the light automatically dims to extend the
duration of the standlight. On another it does not dim and it stays lit
for only a very short time.

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  #92  
Old March 12th 17, 11:21 PM posted to rec.bicycles.tech
James[_8_]
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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.

--
JS
  #93  
Old March 13th 17, 01:27 AM posted to rec.bicycles.tech
JBeattie
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Posts: 5,870
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On Sunday, March 12, 2017 at 7:57:46 AM UTC-7, Joerg wrote:
On 2017-03-11 16:28, Sir Ridesalot wrote:
On Saturday, March 11, 2017 at 10:38:39 AM UTC-5, Joerg wrote:
On 2017-03-10 19:40, Sir Ridesalot wrote:
On Friday, March 10, 2017 at 7:52:30 PM UTC-5, Joerg wrote:
Snipped
With or without dynamo I'll never ride without a battery
because then it's lights out when waiting at an intersection.
Very bad at night.

Now, about the bicycle air conditioner ... :-)

-- Regards, Joerg

http://www.analogconsultants.com/

Most decent dynamo ights these days have a standlight that'll run
for several minutes when the bicycle is stopped.


I have seen that in Germany. Standlight was very dim though. I
prefer it to be lit normal like it is on my bikes.

-- Regards, Joerg

http://www.analogconsultants.com/


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

Why would I want inferior light when I can have a Cree XM-L that affords
me almost the same quality light as a motorcycle has?

This light doesn't just offer a few minutes of "standlight", it offers
north of five hours of light at full blast, whether the bike move or
not. I also have a power outlet on the bike.


Hmm, I've managed without a battery box, outlet and motorcycle light on a road bike for like 50 years. I was riding up and down narrow canyons and city streets today without so much as a blinky. The one car that pulled out in even a semi-perilous fashion did so while looking straight at my son and me. No question of our location on the road. I get cars doing the same thing when I'm in a car. They think they can beat you into traffic.

-- Jay Beattie.


-- Jay Beattie.

  #94  
Old March 13th 17, 11:14 AM posted to rec.bicycles.tech
Duane[_4_]
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Posts: 1,546
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jbeattie wrote:
On Sunday, March 12, 2017 at 7:57:46 AM UTC-7, Joerg wrote:
On 2017-03-11 16:28, Sir Ridesalot wrote:
On Saturday, March 11, 2017 at 10:38:39 AM UTC-5, Joerg wrote:
On 2017-03-10 19:40, Sir Ridesalot wrote:
On Friday, March 10, 2017 at 7:52:30 PM UTC-5, Joerg wrote:
Snipped
With or without dynamo I'll never ride without a battery
because then it's lights out when waiting at an intersection.
Very bad at night.

Now, about the bicycle air conditioner ... :-)

-- Regards, Joerg

http://www.analogconsultants.com/

Most decent dynamo ights these days have a standlight that'll run
for several minutes when the bicycle is stopped.


I have seen that in Germany. Standlight was very dim though. I
prefer it to be lit normal like it is on my bikes.

-- Regards, Joerg

http://www.analogconsultants.com/

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

Why would I want inferior light when I can have a Cree XM-L that affords
me almost the same quality light as a motorcycle has?

This light doesn't just offer a few minutes of "standlight", it offers
north of five hours of light at full blast, whether the bike move or
not. I also have a power outlet on the bike.


Hmm, I've managed without a battery box, outlet and motorcycle light on a
road bike for like 50 years. I was riding up and down narrow canyons and
city streets today without so much as a blinky. The one car that pulled
out in even a semi-perilous fashion did so while looking straight at my
son and me. No question of our location on the road. I get cars doing
the same thing when I'm in a car. They think they can beat you into traffic.


You gotta love the way he starts out telling Sir that Sir is wrong and then
doing exactly what Sir said that he does. :-)

I seem to get by with off the shelf equipment though I readily admit that I
haven't seen a mountain lion in ages.


--
duane
  #95  
Old March 13th 17, 07:06 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 6,016
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On 2017-03-12 13:26, sms wrote:
On 3/10/2017 4:52 PM, Joerg wrote:

With or without dynamo I'll never ride without a battery because then
it's lights out when waiting at an intersection. Very bad at night.


I've been doing a lot of design with Li-Ion batteries lately and I
realized that a dynamo is almost a perfect match for two series Li-Ion
batteries when I was helping a colleague charge his Magicshine pack with
a lab supply set to 8.4VDC.

Think of a dynamo putting out 6VAC, with a full wave Schottky rectifier
you'll get about 8V (8.4V - 0.4V of voltage drop. 8V is just about right
to charge two series Li-Ion batteries. Just in case of high speed
riding, stick in an VLDO like a LT3022 with 145mV drop and you're at
7.855V, still enough to get two series Li-Ion cells to full capacity.
The losses are very low, even lower than a switcher.


If I ever have a hub dynamo I'd use a buck and use a 2nd loop to control
it. The 1st loop would cut the charge if 8.2V has been reached. The 2nd
(inner) loop would set the input voltage to the point where maximum
power is achieved. At the usual brisk ride that most if not all people
in this NG are capable of that voltage level will more likely be well
north of 10V. A dynamo is essentially a current source where you can let
the voltage scoot up until a point is reached where the current drops
off so much that the total power begins to drop. Like MPPT for solar
generation.


The reality is that with protected Li-Ion cells you don't even need the
VLDO since the batteries are protected from charging over 4.2V per cell.


That's how some cheap Chinese chargers work. Not good as that is no
lomnger single-fault safe. It is as if you'd control a pump via tripping
a GFCI when a certain fill level has been reached.


At lower output levels, a dynamo could even run a 2 cell battery powered
light if the batteries were removed.



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.

--
Regards, Joerg

http://www.analogconsultants.com/
  #96  
Old March 13th 17, 07:07 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 6,016
Default More About Lights

On 2017-03-12 13:28, sms wrote:
On 3/11/2017 7:38 AM, Joerg wrote:
On 2017-03-10 19:40, Sir Ridesalot wrote:
On Friday, March 10, 2017 at 7:52:30 PM UTC-5, Joerg wrote: Snipped
With or without dynamo I'll never ride without a battery because
then it's lights out when waiting at an intersection. Very bad at
night.

Now, about the bicycle air conditioner ... :-)

-- Regards, Joerg

http://www.analogconsultants.com/

Most decent dynamo ights these days have a standlight that'll run for
several minutes when the bicycle is stopped.


I have seen that in Germany. Standlight was very dim though. I prefer it
to be lit normal like it is on my bikes.


On one of my dynamo lights the light automatically dims to extend the
duration of the standlight. On another it does not dim and it stays lit
for only a very short time.


Yeah, all they've usually got is a supercap of a few Farads. There is
only so much energy to go around, you can either achieve a dim light or
a longer duration but not both.

--
Regards, Joerg

http://www.analogconsultants.com/
  #97  
Old March 13th 17, 07:09 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 6,016
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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/
  #98  
Old March 13th 17, 07:50 PM posted to rec.bicycles.tech
SMS
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Posts: 9,477
Default More About Lights

On 3/13/2017 11:06 AM, Joerg wrote:

snip

That's how some cheap Chinese chargers work.


And a lot of non-Chinese chargers as well.

Not good as that is no
lomnger single-fault safe. It is as if you'd control a pump via tripping
a GFCI when a certain fill level has been reached.


Technically there are two safety circuits. First, with an 8.4V output
charger you're limiting the charging voltage to 4.2V per cell. Second,
the protection circuit on each battery, or on the battery pack, limits
the voltage to 4.2V per cell just in case someone plugs in a higher
voltage charger.

I think the simplest dynamo to Li-Ion 2S pack circuit would consist of
only three parts. A 2A Schottky bridge. A filter cap. An 8.2V, 5W zener
diode. I don't think you even need a current limiting resistor because
the dynamo isn't going to put out much more than 500mA.

I don't think you gain much with a buck switcher unless you're often
putting out dynamo voltage well in excess of 6VAC, or unless you want to
do 5.25V for USB charging. You're going to lose some power with the
switcher which is likely to be only 85%-90% efficient.

You could stick in a Murata LXDC55FAAA-203
http://power.murata.com/data/power/LXDC55FAAA-203_data_sheet_E.pdf
instead of the zener and do a USB version also with only three parts.
But I know that you love designing your own switchers.

I'm in shock when I see the prices of some of these dynamo to USB
adapters, since the parts cost is only a few bucks.

http://www.sinewavecycles.com/products/sinewave-revolution

Here's someone that did it DIY but using a linear regulator.
http://www.14degrees.org/diy-bicycle-dynamo-usb-charger-for-smartphones-and-battery-packs/


At lower output levels, a dynamo could even run a 2 cell battery powered
light if the batteries were removed.



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.


No, I'm more thinking of a way to have a good light but with dynamo
back-up should the batteries go flat. As well as charging the batteries
during daytime riding when all you're using is the DRL flash mode.

Unfortunately, since dynamo lights are so rare in the U.S. we end up
with sub-standard lighting with poor beam patterns, low intensity, no
flash mode, and inferior brightness when stopped or riding slowly.

I thought it was interesting that Barry Beams mentioned that his light
could work, at less than full intensity, off of dynamo output. He may
have a compelling product for dynamo users that want a brighter, safer,
light but that still want the assurance of not being caught out with
flat batteries. Even Frank realized the need for better lights and
bought an Oculus. And while the Oculus may not be a bargain battery
powered light (even though the price is still pretty reasonable), it's a
lot less than dynamo lights that are not as good.

  #99  
Old March 13th 17, 07:55 PM posted to rec.bicycles.tech
SMS
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Posts: 9,477
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On 3/13/2017 3:14 AM, Duane wrote:

I seem to get by with off the shelf equipment though I readily admit that I
haven't seen a mountain lion in ages.


Come to Cupertino.

http://www.mercurynews.com/2016/06/05/mountain-lion-prompts-park-evacuation-near-cupertino/

A multi-use trail goes right through there.


  #100  
Old March 13th 17, 07:55 PM posted to rec.bicycles.tech
Jeff Liebermann
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Posts: 4,018
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On Mon, 13 Mar 2017 11:06:18 -0700, Joerg
wrote:

A dynamo is essentially a current source where you can let
the voltage scoot up until a point is reached where the current drops
off so much that the total power begins to drop. Like MPPT for solar
generation.


Not exactly a current source. More like a resistor (coil resistance)
in series with an easily saturated inductor[1]. The problem is that
the bicycle dynamo operates over a range of frequencies, while the
typical solar charge controller operates at a fixed frequency. The
inductive reactance of the dynamo winding appears at variable series
resistance that increases as the dynamo goes faster. There are also
substantial differences in operating frequency between bottle and hub
dynamos:
http://www.pilom.com/BicycleElectronics/HubDynamo.htm
"Hubs rotate at a much lower frequency than bottles, and
though they have more poles to somewhat compensate, they still
end up delivering a much lower frequency. At 15 km/h, the
B&M Dymotec6 bottle dynamo (8 poles) outputs 168 Hz AC while
the Shimano DH-3D71 hub dynamo (28 poles) outputs only 28 Hz
at the same speed. At 8 km/h, a 28 pole hub is down to 15 Hz,
which causes visible flicker of the light"

Also, the dynamo iron and number of turns are selected so that the
dynamo saturates at some point near the operating speed and load. The
idea is not so much to regulate the AC output, as it is to reduce
mechanical resistance at higher RPM's.

I tried to build an LTSpice model that simulated a real dynamo and
failed. I couldn't make it act like my bottle dynamo bench tests and
various online graphs. Maybe I'll try again this week. I'm suppose
to be on a (medical) vacation right now.


[1] SON dynamo driving MOSFET bridge:
https://www.flickr.com/photos/kurtsj00/8480800746/in/photostream
http://www.candlepowerforums.com/vb/showthread.php?355392-Spice-code-for-dynamo-output
The author uses 0.1Hy in series with 2 ohm at 30 Hz. When I swept the
30 Hz over a 10 to 50 Hz range, it didn't look much like a dynamo.

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
 




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