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Dynamo/LED power conditioning



 
 
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  #51  
Old May 8th 18, 04:18 AM posted to rec.bicycles.tech
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Default Dynamo/LED power conditioning

On Sunday, May 6, 2018 at 2:19:52 PM UTC-5, AMuzi wrote:
On 5/6/2018 12:50 PM, wrote:
On Sunday, May 6, 2018 at 12:01:24 PM UTC-5, Joerg wrote:

For me the only proper way of lighting a bicycle is with a rechargeable
battery. The LEDs get clean DC and the battery can be recharged from any
source, even a pulsating one. That way the lights will not dim to "stand
light" or go out when waiting at a traffic light. Why should bicycle
lighting be inferior to car lighting?

--
Regards, Joerg


What F-ing world do you live in where you recharge the lights on your car? It must be a pretty F-ed up world. On all the cars I have driven, you turn the switch and the lights come on. There ain't no recharging the car lights. Rechargeable lights and batteries. Why not just duct tape a flashlight to your bars. Then you can stop at any convenience store and buy some new D batteries and ride forever.


I think Joerg meant that the automobile current from a
12~14VAC alternator source gets run through a diode bride
and then (as switched by the regulator) through a lead-acid
pile.

It's a lot of hardware for a bicycle I agree, but Joerg's
seems to work for Joerg's values of performance and
efficiency. Frank & I prefer a simple 6VAC tire drive dynamo
and others extoll USB-LiIon sets or hub dynamos. World's a
big place and people have their own criteria, which are
often inscrutable.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971


I'm a hub dynamo kind of guy. It just works. Don't even have to remember to flip the roller against the tire. As long as the front tire is rolling forward, it works. I agree with this "their own criteria, which are often inscrutable."
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  #52  
Old May 8th 18, 04:23 AM posted to rec.bicycles.tech
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Default Dynamo/LED power conditioning

On Sunday, May 6, 2018 at 5:15:51 PM UTC-5, James wrote:
On 07/05/18 03:01, Joerg wrote:


Note the three big 470uF capacitor in the schematic. That's the "flicker
reduction trick" :-)

Problem is, electrolytic capacitors do not live long in harsh climate
conditions such as the black light enclosure baking in the glistening
Arizona desert sun for hours every week or riding around the Klondike in
a harsh winter.

For me the only proper way of lighting a bicycle is with a rechargeable
battery.


Bull**** alert!

We all know how reliable rechargeable batteries are, especially in harsh
environments, right?

OTOH, here is an electrolytic cap from Vishay, that has a "useful life"
of 1,000,000 hours at 40C, and 8000 hours at 125C.


If I remember my metric system correctly from elementary school or whenever I learned about it. 100C is boiling, 212Fahrenheit. So 125C would be about 250F? At 250F, I'm not sure I'd be worrying about whether my electric cap light was working or not.




https://www.vishay.com/docs/28334/118aht.pdf

(The useful life approximately halves for every 10C increase.)

If the temperature inside the electronics enclosure was much more than
80C for most of the time the light is in operation (E.g. while you're
riding and the light has forced air cooling), the engineer ought to be
shot, and that still gives a useful life of over 62500 hours.

--
JS

  #53  
Old May 8th 18, 04:30 AM posted to rec.bicycles.tech
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Default Dynamo/LED power conditioning

On Sunday, May 6, 2018 at 11:11:14 PM UTC-5, Frank Krygowski wrote:
On 5/6/2018 11:46 PM, bob prohaska wrote:
Joerg wrote:
Why should bicycle lighting be inferior to car lighting?


Does anybody make a bicycle dynamo that produces more than 3 watts
at 10 mph?


The power produced by many (most?) dynamos depends on the load, in a
counterintuitive way. Most dynamos are approximately constant current
(about 0.5 Amp) sources, in the same way that batteries are
approximately constant voltage sources. So if you present more
resistance to the dynamo, its output voltage will rise so as to pump
that same 0.5 Amp through the higher resistance. The result is more
power. Putting two lamps in series does this.

I did this for quite a while as an experiment back in the halogen lamp
days. With my Soubitez roller dyno of the day, I needed something like
14 mph to get both lights brightly lit, so I suppose that was putting
out about six Watts. (A bottle dyno would slip doing that.)

I wouldn't bother with it today, though. What you need for night riding
is not a certain number of Watts, nor a certain number of lumens. You
need sufficient illumination of the road. The better B&M lamps certainly
give that, in spades. Those are so good there's no need to play around
with two lamps or other homebrew tricks, IMO.

--
- Frank Krygowski


I might disagree with you. I have two B&M Cyo LED lights mounted either side of my front hub, driven by a Shimano hub generator. I think they are better than just one Cyo light. You can aim one of them close and one of them far. Good coverage. Its not like one of the Cyo is a spotlight that blinds you. Its OK and usable. But more light at night is good.
  #54  
Old May 8th 18, 04:41 AM posted to rec.bicycles.tech
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Default Dynamo/LED power conditioning

On Monday, May 7, 2018 at 10:31:48 AM UTC-5, Jeff Liebermann wrote:

More problematic is the tail light, which usually runs on alkaline AA
or AAA cells. I haven't seen one with a SoC indicator and would not
expect to see one as the added circuitry and display would probably
cost more than the tail light. So, I run the alkalines until they
die, and carry a few spare NiMH cells which I rotate as needed. With
LSD (low self discharge) NiMH cells, they remain mostly charged for
months.

While just jumping onto the bicycle and going for a ride is a nice
thought, the reality is that we all do some manner of pre-flight check
before riding. So, why is it so painful to add a headlight battery
test to the checklist?


I ride with three tail lights. All powered by AAA batteries. One light clips on the back of my helmet on a zip tie. Its always there because I always wear a helmet. The other two lights are clipped onto my seatbag. I always put the seatbag on the bike I am riding. So I never ever check whether my taillights are working. I always have plenty. Sometimes I stop to turn on my taillights and notice one does not work. Batteries are dead. OK fine. I just turn on the other two and ride home safely. Put new batteries in the bad light when home.

As for pre ride checklists for riding a bike. I check tire pressure with a squeeze or pump up my tires before each ride. That is the total extent of my checking. If something does not work while riding, I fix it on the side of the road (gears not shifting right and need a adjuster turn) or fix it immediately when I get home (chain worn out and skips on cogs). There is never ever a reason to do a pre check on any of my bikes. They are always 100% functional, ready to ride.
  #55  
Old May 8th 18, 04:51 AM posted to rec.bicycles.tech
Andre Jute[_2_]
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Default Dynamo/LED power conditioning

On Tuesday, May 8, 2018 at 2:32:57 AM UTC+1, Jeff Liebermann wrote:
On Mon, 7 May 2018 14:44:34 -0700 (PDT), Andre Jute wrote:

https://swhs.home.xs4all.nl/fiets/tests/verlichting_analyse/dynamos/vergelijking/index_en.html
https://swhs.home.xs4all.nl/fiets/tests/verlichting_analyse/dynamos/dynamos.gif
At 16 km/hr these deliver 3.5 to 4.5 watts, which seems rather high.


Mmm. I measured the hub dynamo in the Shimano Di2 "Smover" full auto group, admittedly a hub dynamo tuned to power not only the lamps but also the sensors and controller unit, plus the switching units for the full-auto gearbox and the electronically active suspension as well. It produced 3.6W at 6kph (1) and 4.8W at 25kph, after which the line flattened sharply; that's a notable performance for a hub dynamo from around the turn of the century that seemed no bigger than the standard top-end dynamo hub then, Shimano's 3DH72.

(1) This is what I meant when I said that in comparison to the slow SON, the Shimano spun up useful lamp output from only a little over walking, keep-your-balance pace.

AJ
Constant load, calmly
  #56  
Old May 8th 18, 11:21 AM posted to rec.bicycles.tech
John B.[_3_]
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Default Dynamo/LED power conditioning

On Mon, 7 May 2018 20:23:54 -0700 (PDT), "
wrote:

On Sunday, May 6, 2018 at 5:15:51 PM UTC-5, James wrote:
On 07/05/18 03:01, Joerg wrote:


Note the three big 470uF capacitor in the schematic. That's the "flicker
reduction trick" :-)

Problem is, electrolytic capacitors do not live long in harsh climate
conditions such as the black light enclosure baking in the glistening
Arizona desert sun for hours every week or riding around the Klondike in
a harsh winter.

For me the only proper way of lighting a bicycle is with a rechargeable
battery.


Bull**** alert!

We all know how reliable rechargeable batteries are, especially in harsh
environments, right?

OTOH, here is an electrolytic cap from Vishay, that has a "useful life"
of 1,000,000 hours at 40C, and 8000 hours at 125C.


If I remember my metric system correctly from elementary school or wheneverr I learned about it. 100C is boiling, 212Fahrenheit. So 125C would be about 250F? At 250F, I'm not sure I'd be worrying about whether my electric cap light was working or not.


257C actually :-) But with electronic stuff it is quite possible for
internal temperatures inside the various electronic devices to be at
much higher temperatures then ambient temperature inside the
enclosure.

Jeff can probably describe LED (for example) temperatures versus
ambient at greater length then the life of the LED at these
temperatures :-)




https://www.vishay.com/docs/28334/118aht.pdf

(The useful life approximately halves for every 10C increase.)

If the temperature inside the electronics enclosure was much more than
80C for most of the time the light is in operation (E.g. while you're
riding and the light has forced air cooling), the engineer ought to be
shot, and that still gives a useful life of over 62500 hours.

--
JS

--
Cheers,

John B.

  #57  
Old May 8th 18, 01:13 PM posted to rec.bicycles.tech
Tosspot[_3_]
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Posts: 1,199
Default Dynamo/LED power conditioning

On 05/07/2018 08:25 PM, Ian Field wrote:

snip

The open voltage on a bottle dynamo can give an impressive belt, not too
sure about hub types.


I can confirm that is in fact the case for hub dynamos :-(

  #58  
Old May 8th 18, 01:23 PM posted to rec.bicycles.tech
Tosspot[_3_]
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Posts: 1,199
Default Dynamo/LED power conditioning

On 05/08/2018 04:18 AM, wrote:
On Sunday, May 6, 2018 at 2:19:52 PM UTC-5, AMuzi wrote:
On 5/6/2018 12:50 PM,
wrote:
On Sunday, May 6, 2018 at 12:01:24 PM UTC-5, Joerg wrote:

For me the only proper way of lighting a bicycle is with a
rechargeable battery. The LEDs get clean DC and the battery can
be recharged from any source, even a pulsating one. That way
the lights will not dim to "stand light" or go out when waiting
at a traffic light. Why should bicycle lighting be inferior to
car lighting?

-- Regards, Joerg

What F-ing world do you live in where you recharge the lights on
your car? It must be a pretty F-ed up world. On all the cars I
have driven, you turn the switch and the lights come on. There
ain't no recharging the car lights. Rechargeable lights and
batteries. Why not just duct tape a flashlight to your bars.
Then you can stop at any convenience store and buy some new D
batteries and ride forever.


I think Joerg meant that the automobile current from a 12~14VAC
alternator source gets run through a diode bride and then (as
switched by the regulator) through a lead-acid pile.

It's a lot of hardware for a bicycle I agree, but Joerg's seems to
work for Joerg's values of performance and efficiency. Frank & I
prefer a simple 6VAC tire drive dynamo and others extoll USB-LiIon
sets or hub dynamos. World's a big place and people have their own
criteria, which are often inscrutable.

-- Andrew Muzi www.yellowjersey.org/ Open every day since 1
April, 1971


I'm a hub dynamo kind of guy. It just works. Don't even have to
remember to flip the roller against the tire. As long as the front
tire is rolling forward, it works. I agree with this "their own
criteria, which are often inscrutable."


Hubdynamo+senso lights. Don't even have to worry about turning them on
and off.


  #59  
Old May 8th 18, 06:50 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 5,536
Default Dynamo/LED power conditioning

On 2018-05-06 15:15, James wrote:
On 07/05/18 03:01, Joerg wrote:


Note the three big 470uF capacitor in the schematic. That's the
"flicker reduction trick" :-)

Problem is, electrolytic capacitors do not live long in harsh climate
conditions such as the black light enclosure baking in the glistening
Arizona desert sun for hours every week or riding around the Klondike
in a harsh winter.

For me the only proper way of lighting a bicycle is with a
rechargeable battery.


Bull**** alert!

We all know how reliable rechargeable batteries are, especially in harsh
environments, right?


I tend not to visit hell or the inside of an erupting volcano while on
my bikes. I also do not find cycling in Siberia in Januray very enticing.


OTOH, here is an electrolytic cap from Vishay, that has a "useful life"
of 1,000,000 hours at 40C, and 8000 hours at 125C.

https://www.vishay.com/docs/28334/118aht.pdf

(The useful life approximately halves for every 10C increase.)

If the temperature inside the electronics enclosure was much more than
80C for most of the time the light is in operation (E.g. while you're
riding and the light has forced air cooling), the engineer ought to be
shot, and that still gives a useful life of over 62500 hours.


I have started using dynamo/battery combo solutions more than four
decades ago. Works fine. Except now that we have high capacity Li-Ion
technology I no longer use a dynamo (though my road bike still has one)
because one charge allows me to ride for 4-5h with the ship lit at full
power. I ride with daytime lights all the time except on bike paths.

--
Regards, Joerg

http://www.analogconsultants.com/
 




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