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SIX thousand and FIVE hundred lumens !!!!!!!!!!



 
 
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  #121  
Old October 8th 18, 05:11 AM posted to rec.bicycles.tech
Jeff Liebermann
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Posts: 4,018
Default SIX thousand and FIVE hundred lumens !!!!!!!!!!

On Sun, 7 Oct 2018 17:38:21 -0400, Frank Krygowski
wrote:

My favorite photo of him was taken when he was one year old. He couldn't
yet talk. But completely on his own, he grabbed a phillips screwdriver
from his dad's tool box, toddled over to his cousin's bike, plugged the
screwdriver into a phillips screw on the bike and tried to loosen it. I
snapped the photo and still have it on my refrigerator.


Very cool. Keep encouraging the kid. However, I have a sad story. My
guess is about 1984. I learned programming from a friend in exchange
for taking care of his computers. He ran a business doing custom
database programs and had a house full of DEC, NCR, and Plexus
computers. He needed me because he literally could not operate a
screwdriver. At first, I didn't believe that it was possible, so I
tried and failed to teach him to work with some basic hand tools. Such
things must be learned at an early age. His father had been an auto
mechanic and didn't want his son to also become an auto mechanic. So,
every time his son would pickup a tool, he would take it away from
him. The result is predictable. He became a very good programmer,
but was useless when it came to working with the hardware.

--
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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  #122  
Old October 8th 18, 05:46 AM posted to rec.bicycles.tech
Jeff Liebermann
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Posts: 4,018
Default SIX thousand and FIVE hundred lumens !!!!!!!!!!

On Sun, 7 Oct 2018 20:37:59 -0700, sms
wrote:

On 10/1/2018 6:29 PM, Jeff Liebermann wrote:

snip

Let's see what the package can do as a heat sink.
Latent heat for aluminum is 0.900 Joules/gm-K.
The light weighs 142 grams, which I'll assume is mostly aluminum.
The light dissipates 71 watts with all the LED's turned on.
I would guess that 75C would be uncomfortably warm for both the
electronics and the bicycle rider. That's a temp rise of 50C (50K).
Joules = Watts * seconds = 71 watts * seconds. Therefo
0.900 = 71 * seconds / (142 * 50)
Time(sec) = 900 seconds = 15 min
Not too horrible. One has 15 minutes of full brightness lighting, in
still air, before the LED's burn your hand or cause a thermal
shutdown.


They even admit that full power requires sufficient airflow requiring
moderate speed to prevent throttling.


Yes, and they little to improve radiation cooling by increasing the
surface area.

A long time ago, one poster here was insisting that one reason LED
lights were so wonderful was the lack of a "white-hot filament." What he
failed to understand was that a high wattage LED has a very hot
semiconductor junction and that extracting the heat from that junction
is a very difficult process, more difficult than cooling an incandescent
or HID lamp. Some LED lights for cars even have fans as part of the
thermal solution.


It doesn't matter how the heat is generated. It could be a carbide
lantern producing the heat, and it still needs to be radiated or
conducted away somewhere.

Still waiting for liquid cooled bicycle lights. I was over at the
Computer History Museum last week where they have several liquid coold
computers on display.


"liquid cooled 500W LED bike lamp"
https://www.youtube.com/watch?v=hYxrpHTEEEQ (6:23)
40,000 lumens. I suppose that dumping hot water on the trail would
work for a while. Otherwise, collect the hot water and use it to make
coffee during the ride.


--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #123  
Old October 8th 18, 07:18 AM posted to rec.bicycles.tech
Jeff Liebermann
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Posts: 4,018
Default SIX thousand and FIVE hundred lumens !!!!!!!!!!

On Sun, 07 Oct 2018 21:46:39 -0700, Jeff Liebermann
wrote:

Yes, and they little to improve radiation cooling by increasing the
surface area.


That should read:
Yes, and they did little to improve radiation cooling
by increasing the surface area.

"liquid cooled 500W LED bike lamp"
https://www.youtube.com/watch?v=hYxrpHTEEEQ (6:23)
40,000 lumens. I suppose that dumping hot water on the trail would
work for a while. Otherwise, collect the hot water and use it to make
coffee during the ride.


I'm not thinking clearly tonite. Never mind making coffee. Add a
steam engine or turbine and use the waste heat and steam to power the
bicycle. That would make it an sBike (steam bike). High power LED's
are about 20% efficient (self heating really reduces efficiency), so
80% of the 500 watts of input power goes into waste heat. That's 400
watts of heat to power the bicycle. If you don't need or want an
sBike, replace the steam engine or turbine with an alternator to
generate electricity to power the light (co-generation) and it help
produce some more runtime.

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #124  
Old October 8th 18, 08:34 AM posted to rec.bicycles.tech
Emanuel Berg[_2_]
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Posts: 1,035
Default SIX thousand and FIVE hundred lumens !!!!!!!!!!

Jeff Liebermann wrote:

Also, one other minor thing. When someone takes
the time to explain how something works,
I suggest you not repackage what they provided
and ask them if that's is what they meant.
Doing that is a trick that students sometimes
do to reverse the situation on their
instructors. Instead of the instructor asking
questions, and the student providing an
explanation or answer, the student ask the
instructor the same question repackaged, and in
effect tests if the instructor understands the
question. The process does not demonstrate that
you've learned anything more than rearranging
a question.


What is happening is the instructor is using
words, phrases and presents a flow of thoughts
and maybe half of that is understood/followed by
the student.

The student tries to explain the same thing,
but in a language and mindset he/she
understands and recognizes, and organizes the
material in a way that makes more sense for
him/her.

E.g.,

Instructor: The sum of 5 and 4 is 9.

Student: You mean if you add 4 to 5, you get 9?

Instructor: Yes.

What has happened? Then student has understood
what is going on, so he or she can sleep at
night, AND s/hes given a chance to acquire
proper terminology.

When you own a tool or piece of technology it
is often very easy to understand what it does
and how it works.. But explaining it to someone
who doest have it, maybe never saw ti, is much
more difficult.


--
underground experts united
http://user.it.uu.se/~embe8573==
  #125  
Old October 8th 18, 03:54 PM posted to rec.bicycles.tech
SMS
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Posts: 9,477
Default SIX thousand and FIVE hundred lumens !!!!!!!!!!

On 10/7/2018 9:46 AM, Jeff Liebermann wrote:

Actually, I know of several. However, they don't deal with literally
everything that walks in the front door. They work out of their
garages and tend to specialize in various areas. Within the general
area where I live, we have repair "shops" for string instruments,
music keyboards, computahs, machine tools, bicycles, mechanical
clocks, etc. They're still around, but because the cost of
maintaining a walk-in store front and hiring employees is so high,
they work out of their houses.


But not a general repair shop.

We went over to Santa Cruz a few years ago to buy a saxophone from a
garage shop. He imports used saxophones from Japan, repairs them, and
resells them, as well as repairing woodwind instruments. He said that
the instruments from Japan usually need very little work, maybe some new
pads. It's quite a business, selling used instruments for about 2/3 the
cost of a new one, and probably paying 1/3 or less. When we got there he
had just sold our first choice to UCSC.
http://stevegraysaxes.com/

Closer to me we have a woodwind repair place operated out of a spare
bedroom in a house. He'll do simple repairs while you wait. The local
music store charges about 5x, is not as skilled, and has a long wait time.
  #126  
Old October 8th 18, 04:53 PM posted to rec.bicycles.tech
SMS
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Posts: 9,477
Default SIX thousand and FIVE hundred lumens !!!!!!!!!!

On 10/7/2018 9:46 AM, Jeff Liebermann wrote:

snip

Nice. There's another difference. He had years of experience, while
you seem to be limiting yourself to what you can learn from a garage
full of old bicycles and parts. That works, to a point, but I think
you will do much better either working for someone else in order to
learn the trade, or working on a better class of bicycle. For bicycle
lighting, there is a difference between cheap junk and a light
designed specifically for a type of bicycle riding. Or, perhaps
building a clone of a high end bicycle light might be ummm...
enlightening. You can buy all the components on eBay. Never mind
what it looks like, build it in a wooden box.


Do not build a high-performance bicycle light in a wooden box!

There's a reason why high-performance bicycle lights use aluminum
enclosures, the thermal solution is the most difficult part of efficient
electronics design, whether it's laptops, phones, mainframes, or bicycle
lights.
  #127  
Old October 8th 18, 07:06 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 6,016
Default SIX thousand and FIVE hundred lumens !!!!!!!!!!

On 2018-10-07 17:08, John B. Slocomb wrote:
On Sun, 7 Oct 2018 15:02:19 -0400, Frank Krygowski
wrote:

On 10/6/2018 2:49 PM, Joerg wrote:


[...]


2. It causes oncoming motorists to see the cyclist much earlier and, for
example, if a big semi comes they can pull a bit to the right so the
semi can give the cyclist wide berth.


I do NOT believe any practical light allows a motorist to see a cyclist
_much_ earlier. In almost every case, I've seen on-road cyclists before
I noticed that they had a light. And in no case did I see the light
early enough to make any practical difference. You're fixating on a
superstitious talisman, imagining benefits that don't exist in real life.



I think I've mentioned seeing the bloke on a bike wearing bright
orange knee socks nearly a kilometer away :-) I remember the orange
socks but can't remember whether he had a light on his bike or not :-)



I wonder what the reaction would be if said bloke participated in a
business meeting wearing bright orange knee socks.

--
Regards, Joerg

http://www.analogconsultants.com/
  #128  
Old October 8th 18, 07:34 PM posted to rec.bicycles.tech
SMS
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Posts: 9,477
Default SIX thousand and FIVE hundred lumens !!!!!!!!!!

On 10/1/2018 7:18 PM, Emanuel Berg wrote:
Jeff Liebermann wrote:

Ok, let's do the math.


I put a flashlight to the handlebars the other
day with re-openable cable ties. It seems to
work OK, a pretty solid fix. I cut the cable
ties with a combination plier so it looks neat
as well.

The flashlight is 3*AAA batteries with
9 diodes. How many lumens is that, do
you think?

I think I should get a proper bicycle light
soon tho.


The problem with 3AA batteries is that the run-time of a reasonably
powered light would be very low. There are a few lights with 3AA
batteries. but not many.

By the time you buy rechargeable NiMH cells, a charger, a suitable
light, you may as well buy a purpose-built bicycle light.

I picked up a light at Interbike on the last day (when the exhibitors
try to sell the booth demos so they don't have to ship them back). I
actually didn't save much but I got it right away.

https://www.aliexpress.com/item/GACIRON-professional-Bicycle-Light-Power-Bank-Waterproof-USB-Rechargeable-Bike-Light-Side-Warning-Flashlight-1600-Lumen/32802747811.html

There are a couple of good features that I like. The "breathe mode" is a
good daytime running light, lower power and not a strobe, but a
modulated pattern. It can be used to charge a phone via the USB-A port.
It is charged via MicroUSB.

1600 lumens is sufficient for road riding. I also have a dynamo light on
the bike but it's not really sufficient for very dark paths.



  #129  
Old October 8th 18, 08:00 PM posted to rec.bicycles.tech
SMS
external usenet poster
 
Posts: 9,477
Default SIX thousand and FIVE hundred lumens !!!!!!!!!!

On 10/8/2018 11:34 AM, sms wrote:

snip

There are a couple of good features that I like. The "breathe mode" is a
good daytime running light, lower power and not a strobe, but a
modulated pattern. It can be used to charge a phone via the USB-A port.
It is charged via MicroUSB.


I also like that they sell extra mounting brackets fairly inexpensively
so you can use one light on multiple bikes without having to move the
mount between bikes.
https://www.aliexpress.com/item/GACIRON-Universal-Bicycle-Handlebar-Mount-Cell-Phone-GPS-Holder-with-3M-Back-Sticky-Pad-for-Smart/32795618775.html
  #130  
Old October 8th 18, 08:24 PM posted to rec.bicycles.tech
Jeff Liebermann
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Posts: 4,018
Default SIX thousand and FIVE hundred lumens !!!!!!!!!!

On Mon, 8 Oct 2018 08:53:19 -0700, sms
wrote:

On 10/7/2018 9:46 AM, Jeff Liebermann wrote:

snip

Nice. There's another difference. He had years of experience, while
you seem to be limiting yourself to what you can learn from a garage
full of old bicycles and parts. That works, to a point, but I think
you will do much better either working for someone else in order to
learn the trade, or working on a better class of bicycle. For bicycle
lighting, there is a difference between cheap junk and a light
designed specifically for a type of bicycle riding. Or, perhaps
building a clone of a high end bicycle light might be ummm...
enlightening. You can buy all the components on eBay. Never mind
what it looks like, build it in a wooden box.


Do not build a high-performance bicycle light in a wooden box!


The package might have an effect on cooling the LED and electronics,
but that's not an issue here, where a proper beam footprint and
battery life are more important. The exercise will be in optics,
current regulation, beam pattern optimization, measurements, testing,
and the reality of such mundane problems such as high resistance
battery contacts, lossy components, junk eBay electronics, etc. I
agree that thermal management is important, but that can be done later
or when a proper package has been designed. Think of it more like an
optical bench than a streamlined finished product.

Well, maybe you're right. Instead of a wooden box, substitute an
aluminum mini-box to take advantage of better heat dissipation:
https://www.google.com/search?q=cast+aluminium+box&tbm=isch
Or maybe a plastic box with a clear cover so he can better see what's
happening inside:
https://www.google.com/search?tbm=isch&q=plastic+project+box+clear+cover
Remember, the uglier the construction, the better it will work.

There's a reason why high-performance bicycle lights use aluminum
enclosures, the thermal solution is the most difficult part of efficient
electronics design, whether it's laptops, phones, mainframes, or bicycle
lights.


Yep. I've seen a few high power bicycle light prototypes with built
in fans to cool the LEDs. Also, one with an scoop air intake for
improved internal air flow. LED output is higher at lower
temperatures.

You might be amused with the various flashlight forums for the latest
in high fashion, errr... high performance lighting:
https://www.candlepowerforums.com
http://budgetlightforum.com
Copper packaging and cooling has been fashionable for about 2 years.
Never mind that a metallic copper finish is a worse heat radiator than
an anodized black aluminum finish. Of course, some of these are
copper plated or painted aluminum:
https://www.google.com/search?q=copper+flashlight&tbm=isch
Sometimes, the original reason for using copper is lost and the
fashion thing takes over:
https://www.edcforums.com/threads/show-your-flashlight-patina.127703/
Sigh.

Anyway, I would be quite satisfied if Emanuel Berg were to build
something resembling a bicycle light from scratch, measures the
lumens, lux, candelas, beam pattern, variation in intensity across the
beam pattern, power draw, operating temperature, and then improves the
design updating the measurements as he makes changes.


--
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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