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  #81  
Old March 11th 17, 01:51 AM posted to rec.bicycles.tech
SMS
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On 3/10/2017 3:30 PM, Jeff Liebermann wrote:
On Wed, 8 Mar 2017 09:39:28 -0800, sms
wrote:

On 3/6/2017 6:27 PM, Jeff Liebermann wrote:


http://www.ebay.com/itm/142066277090
$0.97 gets you a two AAA batteries packaged inside a flasher


You used to be able to get 2xAA powered flashers, but they weren't 97¢


I haven't seen any with AA batteries in many years. All the cheap
ones seems to AAA.


But you can still get at least one not-cheap one.

https://www.amazon.com/dp/B00MQPEW10
https://www.aliexpress.com/item/CATEYE-2015-New-Bike-Light-Rear-Tail-Light-Warning-Lamp-Safety-Flashlight-Red-Lights-LD1100-Bicycle/32596712188.html
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  #82  
Old March 11th 17, 01:52 AM posted to rec.bicycles.tech
Joerg[_2_]
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On 2017-03-10 11:45, jbeattie wrote:

[...]


If you're riding a lot during the day with a DRL then you really
should consider a dyno light. I was riding with my son this morning,
and we passed a guy with a DRL, and I thought that it was
unnecessarily bright for a DRL -- and goddamn if it wasn't a
round-beam Supernova E3. The two of us were DRL-less, although I was
personally in need of recharging.


To some extent. I found that when car drivers in an urban area are
particularly inattentive and I switch my front light from 3.5W to 8W
that does get their attention much better. A dynamo can't muster that
much oomph in normal city riding.

On county roads I always ride with full LED power. I found that oncoming
vehicles see me earlier and veer right a bit to give traffic in my
direction more room and thus me a better clearance. Flash mode would be
as bright and save 50% power but that is very annoying to others.

When my front rim is up I will look for a complete wheel or wheel set
with a hub dynamo as long as the cost for the front wheel is under $100.
The value of such a dynamo is limited in this day and age of powerful
Li-Ion batteries. My bigger battery has 60Wh of usable capacity which
means I can ride over 5h with the ship fully lit, music blaring and all
that. A typical dynamo goosed to 5W or so would need at least 20 hours
of solid riding to recharge such a large battery when depleted.
Realistically all a dynamo would do is extend the battery runtime and I
could reduce the size of the battery. That is an advantage but not a big
one because the weight saved by removing two or four 18650 cells is not
that great considering that the hub dynamo adds weight back.

If there'd be a way to goose a dynamo to 10W that would be a different
story. One has to keep in mind that some cyclists want more than just
light. In my case it is just an MP3 player but others have a GPS and a
smart phone. Easily another 3-5W.

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/
  #83  
Old March 11th 17, 03:11 AM posted to rec.bicycles.tech
John B.[_3_]
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On Fri, 10 Mar 2017 15:19:11 -0800, Jeff Liebermann
wrote:

On Wed, 8 Mar 2017 09:45:43 -0800, sms
wrote:

On 3/6/2017 9:22 AM, Jeff Liebermann wrote:

Kinda looks like all of them will sorta deliver 2.5 watts before the
core saturates (to provide some level of voltage regulation). Further
down the page is a "Low Speed Power" graph, which shows that most can
produce 2.0-2.5 watts at 10km/hr. One could assume that the dynamo
will deliver 4.0 watts, but that would require buying one of the few
better (hub) dynamos listed, and riding at 25-30km/hr (15-19mph).

If I were designing or sizing a lighting system suitable for my slow
style of "cruising", I would use the worst case 10km/hr (6mph) and 2.0
watt figures.


You've touched on one of the reasons why dynamo lights haven't caught on
in the U.S..


Touched? I was trying to sledge hammer the reason. Basically, one
design is not going to make everyone happy. Some riders can easily
maintain the speeds necessary to utilize the dynamo at well above it's
rated capacity. Others, like me, can barely make it spin.

I'll spare you my rant on the benefits of a hybrid battery + dynamo
system.

I wish that it were possible for inexpensive, dynamo powered lights to
provide adequate illumination for commuting, but it isn't. I recognize
that few people can afford nearly $500 for a hub dynamo wheel and a
SuperNova E3 Triple 2. For commuting, where there is no problem
charging batteries every night, a high power LED set-up is more
economical and provides better illumination. It's hard enough getting
people to spend even $25 on a bicycle light, getting them fork out $500
for a dynamo wheel and a decent dynamo light would be damn near impossible.


So how duz it cost to build one dynamo wheel and headlight?
Prices are my guess(tm) based on experience and random googling.

Shimano Nexus series hubs can be found for about $70.
Wheelsmith spokes are about $0.50/ea or 26 for $18.
Generic rim for $35.
Tire, tube, and rim tape for $20.
B&M Lumotec LUXOS B for $64.
Wiring for free.
====================================
total = $207

While $207 is not cheap, it's much less than your $500 estimate.


The logic of paying $207 dollars for something I never use is
irrefutable :-)
--
Cheers,

John B.

  #84  
Old March 11th 17, 04:40 AM posted to rec.bicycles.tech
Sir Ridesalot
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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.

Cheers
  #85  
Old March 11th 17, 09:35 AM posted to rec.bicycles.tech
Sepp Ruf
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Jeff Liebermann wrote:
On Fri, 10 Mar 2017 17:30:57 -0600, AMuzi wrote:

So how duz it cost to build one dynamo wheel and headlight?
Prices are my guess(tm) based on experience and random googling.

Shimano Nexus series hubs can be found for about $70.
Wheelsmith spokes are about $0.50/ea or 26 for $18.


Typo. That should be 36 spokes for $18.

Generic rim for $35.
Tire, tube, and rim tape for $20.
B&M Lumotec LUXOS B for $64.
Wiring for free.
====================================
total = $207

While $207 is not cheap, it's much less than your $500 estimate.


Low price but no actual German electrons. You call that a
fashion statement?


Well, Japanese and German electrons should be compatible. However,
the cost of the SON hub needed to produce genuine German electrons is
well over $200. That brings the cost of the wheel to $337. The
prices I picked out of thin air are the cheapest that I could find new
from vendors that sell component parts. I specifically did not use
Banggood and AliExpress to avoid counterfeits and junk. Modifying an
existing front wheel would save $55 for the rim, tire, and tube. Even
running on Japanese electrons, it's still a rather expensive solution
compared to a battery powered headlight and goes a long way to explain
why battery powered lights are more common.


Under strict Japanese supervision, even Indonesian electrons work:
https://www.rosebikes.co.uk/article/aid:671388

  #86  
Old March 11th 17, 04:38 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 6,016
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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/
  #87  
Old March 12th 17, 01:28 AM posted to rec.bicycles.tech
Sir Ridesalot
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Posts: 5,270
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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.

Cheers
  #88  
Old March 12th 17, 01:31 AM posted to rec.bicycles.tech
Sir Ridesalot
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Posts: 5,270
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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 at more modern stuff in North America because now many hub dynamos have standlights that are quite bright and stay on for a number of minutes if you need them to.

Cheers
  #89  
Old March 12th 17, 03:57 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 6,016
Default More About Lights

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.

--
Regards, Joerg

http://www.analogconsultants.com/
  #90  
Old March 12th 17, 09:26 PM posted to rec.bicycles.tech
SMS
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Posts: 9,477
Default More About Lights

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.

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.

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




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