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Dynamo/LED power conditioning



 
 
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  #41  
Old May 7th 18, 07:24 PM posted to rec.bicycles.tech
Sepp Ruf
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Posts: 217
Default Dynamo/LED power conditioning

Jeff Liebermann wrote:
bob prohaska wrote:
Joerg wrote:
Why should bicycle lighting be inferior to car lighting?


Easy one: Because Joerg messed with it.

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


Shimano; .... Does this link
http://www.pilom.com/BicycleElectronics/DynamoCircuits.htm look familiar??

I couldn't find any, but they might exist. What I found were plenty
that claimed as high as 15 watts, but didn't bother mentioning what
rpm, mph, or kph was required.


How come rbt's trade fair expert Scharfie hasn't yet gotten ahold of a Neco
Rove to guerilla_market? Andreas Oe. has:
https://fahrradzukunft.de/26/steckdose-unterwegs-6/
Ads
  #42  
Old May 7th 18, 08:11 PM posted to rec.bicycles.tech
Jeff Liebermann
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Posts: 2,907
Default Dynamo/LED power conditioning

On Mon, 7 May 2018 20:24:58 +0200, Sepp Ruf
wrote:

Jeff Liebermann wrote:
I couldn't find any, but they might exist. What I found were plenty
that claimed as high as 15 watts, but didn't bother mentioning what
rpm, mph, or kph was required.


How come rbt's trade fair expert Scharfie hasn't yet gotten ahold of a Neco
Rove to guerilla_market? Andreas Oe. has:
https://fahrradzukunft.de/26/steckdose-unterwegs-6/


Looking at the graph in Fig 13, 16 kph produces 1 to 3.5 watts. What's
different is that this dynamo does not saturate and continutes to
produce higher power output when spun faster.

If my German is still functional, Fig 4 says in the caption 15 watts
at 12 km/h. However, the English language text in Fig 4 says "With
riding speeds up to 12 km/h... can supply 0.5 to 2.5A. That makes no
sense and contradicts the numbers from Fig 13.

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #43  
Old May 7th 18, 08:25 PM posted to rec.bicycles.tech
Ian Field
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Posts: 250
Default Dynamo/LED power conditioning



"David Scheidt" wrote in message
news
sms wrote:
:On 5/2/2018 7:49 PM, bob prohaska wrote:
: I finally caved and bought a Shimano dh-3n72 hub for use on my
: exercise bike. It works fine, but the LEDs flicker quite noticeably
: at all speeds. The circuit puts series trios of LEDs in inverse
: parallel across the dynamo, so each trio lights on alternate half-
: cycles. The flicker wasn't visible with the old Soubitez roller,
: because it was working at about 6x higher frequency. The circuit is at
: http://www.zefox.net/~bob/bicycle/schematic.gif
: The point of the design is to eliminate rectifier losses, which are
: substantial at low voltage.
:
: The new setup might be ok for fast riding. At low speeds and in traffic
: I'm less sure I'll like it and fairly certain bystanders won't like it
: at all, especially at night. As a DRL it certainly aids conspicuity 8-)
:
: Can anybody point me to a discussion of what outfits like B&M use in
: their dynamo-powerd LED headlights? I've searched intermittenly but
: never hit the right keywords.
:
: Thanks for reading, and any guidance.
:
: bob prohaska

:I suspect that they use a Schottky Bridge Rectifier, with a capacitor
:across the DC output, plus a couple of farads for any standlight that
:switches in when stopped.

I would not be at all surprised if the better stuff (where better
needn't mean 'more expensive' just 'better design' or maybe just
'newer design') is using a MOSFET brige. One for a bike light
wouldn't be terribly expensive, and they're substantially more
efficent than a schottky is.


SB rectifiers are rarely rated more than 60V - anything higher gets
seriously expensive.

Most of that type of AC generator vaguely resemble constant current
sources - the off load voltage can get a bit naughty.

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

Clearly; an intermittent fault in the load would kill the rectifier.

  #44  
Old May 7th 18, 10:41 PM posted to rec.bicycles.tech
Sepp Ruf
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Posts: 217
Default Dynamo/LED power conditioning

Jeff Liebermann wrote:
On Mon, 7 May 2018 20:24:58 +0200, Sepp Ruf wrote:


https://fahrradzukunft.de/26/steckdose-unterwegs-6/


Looking at the graph in Fig 13, 16 kph produces 1 to 3.5 watts. What's
different is that this dynamo does not saturate and continutes to
produce higher power output when spun faster.

If my German is still functional, Fig 4 says in the caption 15 watts
at 12 km/h. However, the English language text in Fig 4 says "With
riding speeds up to 12 km/h... can supply 0.5 to 2.5A. That makes no
sense and contradicts the numbers from Fig 13.


Looks like a triple complication the

a) Fig 4's Chinese marketing English;
b) the anti-functional German grammar putting the key verb at the very end;
c) the caption author's consumer-friendly (mis)interpretation of a), as his
caption reads "... which is claimed ["verspricht" does not solely mean
"promises"] to deliver an impressive 15W at just 12 km/h."

The paragraph beneath Fig 14 reads:

The Neco Rove hub dynamo with ballast electronics only starts to deliver
significant charging current from 15 km/h in the 28" wheel. The 12 km/h
mentioned in the Neco advertising are thus to be understood as the minimum
speed for a loading process in the 26" wheel. There, however, not - as can
easily be misunderstood - 15 watts, but only 0.15 watts are supplied. Only
at over 20 km/h can you reach the range of over 2 watts that a modern
smartphone needs in operation. The advertised 15 watts of USB are only
reached at 50 km/h. (....)

(Translated with www.DeepL.com/Translator, which Elon Musk would not
hesitate to call Multi Language Auto Pilot.)
  #45  
Old May 7th 18, 10:44 PM posted to rec.bicycles.tech
Andre Jute[_2_]
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Posts: 8,783
Default Dynamo/LED power conditioning

On Monday, May 7, 2018 at 5:05:52 PM UTC+1, Jeff Liebermann wrote:

From the graphs:
http://www.myra-simon.com/bike/dynotest.html
at 16 kph, the range of output power is 2.5 to 3.4 watts.


That data was already ancient when I first saw it, c2002. One would hope that present-day hub dynamos are a spot more efficient.

With a hub dynamo, you're kinda stuck with the available products,
most of which max out at 3 watts at 10 mph.


A spot under, actually, 15kph, which isn't quite 10mph; it's the highest speed a lady commuter cyclist or housewife doing her shopping was assumed to aspire to. This is another example of thick German legislators setting a "standard" hostile to cyclists in cement. The EU, within which all nations generally follow the German bicycle legislation, is such a large market for hub dynamos, that even Shimano, a Japanese company, follows the German standard -- and of course doesn't want the costs of making two different classes of hub dynamos. That's how the 6V/0.5A/3W standard arose, not by conspiracy but by ignorant Teutonic lack of foresight (1). By now there's too much invested in that "standard" for it to change, so we can only hope that the lighting elements have another sudden splurge of development.

I am of the opinion, though, that an up-to-date hub dynamo (a correctly scaled SON, a Shimano, any of the latest contenders) attached to a BUMM Cyo or better makes the first adequate bicycle lamp, at the level of an old 6V VW Beetle from around the time you were in college, Jeff. A blinkie, verboten by the German "standard", is easily and cheaply added with a Chinese LED torch and a fish mouth or tiewrap mounting.

AJ
Rage, rage against the dying of the light -- Dylan Thomas

(1) Mind you, we should probably be grateful that those dim dead Germans didn't define some output equivalent to incandescent filaments back then, because in that case by now the only available hub dynamos would put out 0.5W.
  #46  
Old May 7th 18, 10:47 PM posted to rec.bicycles.tech
Andre Jute[_2_]
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Posts: 8,783
Default Dynamo/LED power conditioning

On Monday, May 7, 2018 at 10:41:18 PM UTC+1, Sepp Ruf wrote:
Jeff Liebermann wrote:
On Mon, 7 May 2018 20:24:58 +0200, Sepp Ruf wrote:


https://fahrradzukunft.de/26/steckdose-unterwegs-6/


Looking at the graph in Fig 13, 16 kph produces 1 to 3.5 watts. What's
different is that this dynamo does not saturate and continutes to
produce higher power output when spun faster.

If my German is still functional, Fig 4 says in the caption 15 watts
at 12 km/h. However, the English language text in Fig 4 says "With
riding speeds up to 12 km/h... can supply 0.5 to 2.5A. That makes no
sense and contradicts the numbers from Fig 13.


Looks like a triple complication the

a) Fig 4's Chinese marketing English;
b) the anti-functional German grammar putting the key verb at the very end;
c) the caption author's consumer-friendly (mis)interpretation of a), as his
caption reads "... which is claimed ["verspricht" does not solely mean
"promises"] to deliver an impressive 15W at just 12 km/h."

The paragraph beneath Fig 14 reads:

The Neco Rove hub dynamo with ballast electronics only starts to deliver
significant charging current from 15 km/h in the 28" wheel. The 12 km/h
mentioned in the Neco advertising are thus to be understood as the minimum
speed for a loading process in the 26" wheel. There, however, not - as can
easily be misunderstood - 15 watts, but only 0.15 watts are supplied. Only
at over 20 km/h can you reach the range of over 2 watts that a modern
smartphone needs in operation. The advertised 15 watts of USB are only
reached at 50 km/h. (....)

(Translated with www.DeepL.com/Translator, which Elon Musk would not
hesitate to call Multi Language Auto Pilot.)


You expect too much, Sepp. Precision, honesty in advertising, even common sense -- any economist will tell you that today those are unpriceable commodities because they are so rare that they are beyond price.

AJ
Dismally yours
  #47  
Old May 7th 18, 10:49 PM posted to rec.bicycles.tech
James[_8_]
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Posts: 5,767
Default Dynamo/LED power conditioning

On 07/05/18 23:43, Theodore Heise wrote:
On Mon, 7 May 2018 13:21:02 +0000 (UTC),
David Scheidt wrote:
Theodore Heise wrote:

:Someone noted elsethread the great variation in user requirements,
:and the choice between dynamos and rechargeables is certainly
:affected by them. I need a light only infrequently, so for me a
:dynamo would largely be wasted weight and clutter on the bike. On

Ah, but it would just work. Get on the bike, and ride. a
rechargable light would have to be found, put on the bike, and
discover the batteries are dead.


Sure, I get that--and don't disagree. But for me, the effort to
find the light, have a charged battery, and mount it is small. I
keep things in established places, and plan ahead. The risk of
failure is acceptable (to me).

On the other hand, I rarely need the light, and like having the
handlebar real estate available for other things.


I don't clutter my handlebars with a lighteither. The light is mounted
on the fork crown using the front brake centre bolt.

I rarely use a light, but the other morning I found it was a bit foggy
_after_ I had left home, so I turned my lights on for the first hour.

--
JS
  #48  
Old May 8th 18, 02:32 AM posted to rec.bicycles.tech
Jeff Liebermann
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Posts: 2,907
Default Dynamo/LED power conditioning

On Mon, 7 May 2018 14:44:34 -0700 (PDT), Andre Jute
wrote:

On Monday, May 7, 2018 at 5:05:52 PM UTC+1, Jeff Liebermann wrote:

From the graphs:
http://www.myra-simon.com/bike/dynotest.html
at 16 kph, the range of output power is 2.5 to 3.4 watts.


That data was already ancient when I first saw it, c2002.
One would hope that present-day hub dynamos are a spot more efficient.


Well if you insist:
http://pilom.com/BicycleElectronics/HubDynamo.htm
At 16 km/hr, the Shimano DH-3D71 hub dynamo delivers 4.0 watts, while
the B&M Dymotec 6 bottle dynamo delivers 2.8 watts. Notice that the
graphs were generated with different constant current loads
(simulating an LED).

http://pilom.com/BicycleElectronics/Dynamo.htm
At 15 km/hr (slightly less than 10 mph), the various dynamos deliver
between 2.2 and 3.0 watts.

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.

With a hub dynamo, you're kinda stuck with the available products,
most of which max out at 3 watts at 10 mph.


I am of the opinion, though, that an up-to-date hub dynamo (a
correctly scaled SON, a Shimano, any of the latest contenders)
attached to a BUMM Cyo or better makes the first adequate bicycle
lamp, at the level of an old 6V VW Beetle from around the time
you were in college, Jeff. A blinkie, verboten by the German
"standard", is easily and cheaply added with a Chinese LED torch
and a fish mouth or tiewrap mounting.


I'm not that old. VW "bugs", the preferred transportation of
impoverished students, were all 12V when I attended college.

My rule of thumb is currently 100 lumens/watt for cheap LED lights and
150 lumens/watt for the very best, bin selected, LED lights. At 10
mph (16 km/hr), I would expect an average of about 3.5 watts from the
various dynamos, thus delivering an average of:
150 * 3.5 = 525 lumens
The light manufacturer claims more, then they're probably doing
something clever, stupid, or evil.

Rage, rage against the dying of the light -- Dylan Thomas


Now that you mention it, LED's do age and decrease in output:
http://www.climateactionprogramme.org/images/uploads/documents/Philips_Understanding-Power-LED-Lifetime-Analysis.pdf
Or, maybe it's my eyes that are rapidly deteriorating? However, at
the runtime and power level of bicycle headlights, aging shouldn't be
a problem unless you plan to deliver megalumens.





--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #49  
Old May 8th 18, 03:08 AM posted to rec.bicycles.tech
Frank Krygowski[_4_]
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Posts: 6,316
Default Dynamo/LED power conditioning

On 5/7/2018 11:31 AM, Jeff Liebermann wrote:
On Mon, 7 May 2018 13:21:02 +0000 (UTC), David Scheidt
wrote:

Theodore Heise wrote:

:Someone noted elsethread the great variation in user requirements,
:and the choice between dynamos and rechargeables is certainly
:affected by them. I need a light only infrequently, so for me a
:dynamo would largely be wasted weight and clutter on the bike. On

Ah, but it would just work. Get on the bike, and ride. a rechargable
light would have to be found, put on the bike, and discover the
batteries are dead.


Assuming you own an automobile, what do you check before you go for a
ride or drive? Got enough gasoline? Fluid levels within limits? Tire
pressure look normal? Engine warning light on? For fanatics, does
the add-on OBD II display panel show anything unusual? Having driven
rolling wrecks during college, walking around the vehicle to see what
has fallen off or was stolen in the night was a regular ritual.

Same with my bicycles. Do you check the air pressure in your tires
before riding? I don't, but I give the tires a good squeeze as a
crude pressure check and pump as needed. My favorite mistakes are a
loose quick release, a loose nut from an unfinished repair, and my
folding pedals in the folded position. I take a quick look at the
frame and gears for any sign of damage. I check for my seat bag of
tricks, which contains tools, parts, munchies, and a few dollars.

Batteries do not provide a visual or mechanical indication of SoC
(state of charge), but you can add something like this:
https://www.ebay.com/itm/Lithium-ion-Charging-Battery-Voltage-Capacity-Percent-Level-LED-Indicator-18650/181692946263
Some headlights have a similar indicator built in. I use a DVM
(digital voltmeter) instead.

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?


Oddly enough, with both the car and the bike (and the motorcycle) I
don't have a checklist, at least for ordinary day-to-day trips. I just
get moving.

I used my utility bike today to go out to get some food for dinner. I
clipped on my eyeglass mirror, used safety pins to contain the cuffs of
my jeans, and pedaled off. I suppose I may have glanced down as I left
the drive to be sure my tires weren't low on air, but maybe not.

It was not long before sunset. I didn't even think about lights, because
I never have to on the bike, except that when it gets dark, I turn them
on. Just like the car and the motorcycle.

Tomorrow we'll be taking our folding bikes with us on a little trip. I
won't check anything before I pack them, because we used them a few days
ago and they were fine. I certainly won't check the lights. They just work.

--
- Frank Krygowski
  #50  
Old May 8th 18, 03:27 AM posted to rec.bicycles.tech
Frank Krygowski[_4_]
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Posts: 6,316
Default Dynamo/LED power conditioning

On 5/7/2018 5:49 PM, James wrote:
On 07/05/18 23:43, Theodore Heise wrote:

On the other hand, I rarely need the light, and like having the
handlebar real estate available for other things.


I don't clutter my handlebars with a light either.* The light is mounted
on the fork crown using the front brake centre bolt.


I find that lamp position is best for several reasons.

1) It seems to be optimum height for lighting the road and displaying
potholes or obstacles via their shadows. (If the light beams coincide
with the line of one's vision, as with a head-mounted lamp, shadows are
not visible. The image looks flat.)

2) It leaves room for a cyclometer, a bell, and I suppose a smartphone
if you're into that.

3) It doesn't interfere with handlebar bags. As a bonus, the bag helps
prevent any irritation from glare from the edge of the lenses, if your
lamp has that defect.

4) It's bolted on, so it can be precisely and permanently aimed.

5) It's bolted on, so there is much less worry about it being nicked.


--
- Frank Krygowski
 




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