A Cycling & bikes forum. CycleBanter.com

Go Back   Home » CycleBanter.com forum » rec.bicycles » Techniques
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

More About Lights



 
 
Thread Tools Display Modes
  #151  
Old March 15th 17, 08:13 PM posted to rec.bicycles.tech
AMuzi
external usenet poster
 
Posts: 8,261
Default More About Lights

On 3/15/2017 2:57 PM, Frank Krygowski wrote:
On 3/15/2017 2:48 PM, Sir Ridesalot wrote:
On Wednesday, March 15, 2017 at 2:08:49 PM UTC-4, Frank
Krygowski wrote:
On 3/14/2017 11:15 PM, Jeff Liebermann wrote:
On Tue, 14 Mar 2017 12:09:27 -0400, Frank Krygowski
wrote:
But the point I was discussing was whether too brief or
too dim
standlights really kill or seriously injure
_stationary_ bicyclists.
I've never heard of such a case. I think it's yet
another exaggerated
danger.

Bicycle lighting seems to be divided into "see where
your going" and
"be seen" parts. Standlights are in the "be seen"
part. If so, then
using a relatively narrow forward facing headlight is
inadequate and a
poor substitute for all around "be seen" type lighting.

So far, no driver has tried to kill me while I'm
stationary, but it's
possible. To help prevent such a threat, I would need
all around
illumination because I don't know from what direction
the driver might
approach and I do NOT need to see where I'm going
(because I'm not
going anywhere). Some kind of flashing headband,
flashing arm bands,
or maybe downward facing flood lights to illuminate an
area. Maybe an
LED illuminated vest, which is now popular among highway
workers:
https://www.amazon.com/HIGH-VISIBILITY-VEST-COMPLIANT-REFLECTIVE/dp/B01L2US0EY

https://www.amazon.com/SE-EP08L-Illuminated-Flashing-Feature/dp/B008WAE2XQ

https://www.amazon.com/SE-EP07L-Flashing-Illuminated-Safety/dp/B004J663A2

I don't know which type of "be seen" lighting might be
most effective,
but any of the aformentioned would be better than a dim
forward facing
standlight.

Thing is, nobody's demonstrated any need for so much
stationary "be
seen" light, beyond the usual "well, it _could_ happen"
safety inflation
mentality.

We're facing the same mentality regarding our local
forest preserve.
Some people want to cut down every dead or dying tree
within 100 feet of
any trail because, well, it _could_ fall on somebody and
kill them. Sheesh.


--
- Frank Krygowski


I remember the Soubitez (sp?) ads from the 1980s that
showed a stopped bicycle without a front light at an
intersection at night and another image of the Soubitez
dynamo light with the standlight. The ad was about how
much safer yuo were with the Soubitez dynamo because
others could see the light whilst you were stopped or just
starting up again. So this perceived need for a safety
standlight on a dynamo powered light is nothing new.


As I recall, that system failed in the marketplace. The
idea might have existed in a few minds back then, but it
wasn't common enough to be commercially successful.

The same could be said of many present "safety" devices.
You'd have gone broke trying to sell "walker safety vests"
in the 1970s or 1980s. Ditto little hammers to let you break
your car window if you were trapped inside. Or foam pads to
put on the corner of every hard object your toddler might
walk by. Or bathtub mats that say "HOT" when the water is,
well, hot. But all those things have been sold recently.



None anywhere near as lucrative as Pet Rocks (a product of
similar utility but more trendy)

Regarding Soubitez standlights of the 1980s, devastatingly
unpopular.
http://www.yellowjersey.org/photosfr...t/soustan1.jpg
http://www.yellowjersey.org/photosfr...t/soustan2.jpg




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


Ads
  #152  
Old March 15th 17, 08:27 PM posted to rec.bicycles.tech
JBeattie
external usenet poster
 
Posts: 2,281
Default More About Lights

On Wednesday, March 15, 2017 at 12:17:31 PM UTC-7, David Scheidt wrote:
jbeattie wrote:
:On Wednesday, March 15, 2017 at 7:53:52 AM UTC-7, David Scheidt wrote:
: Sir Ridesalot wrote:
:
: :I remember burning out bulbs with my bottle dynamo if I rode really
: :fast. I also remember the slipping problems when the wheels were wet even
: :when I used the rubber boot sold to go on the bottle dynamo roller. Hub
: :dynamos today really seem to fall down at slow speeds.
:
: Mine work fine from walking speeds. They produce more light at higher
: speeds, but at slow speeds you don't need it, because you're not
: moving fast.
:

:I sometimes need light most at slow speeds, when I'm creeping up hills and trying not to fall into giant pot holes.

I assure you the potholes in Chicago are as least as big as yours, and
my lights are fine for finding them as slow as I can ride a bike
upright. Perhaps your hub is defective.


Perhaps I do have a defective hub. Unlike Chicago, though, I'm riding home up little goat roads that are between a 6-10 percent grade and that are really a collection of patch and broken pavement. http://tinyurl.com/zo6hq6e

Scoll up the road. A lot of the patched sections are now holes after the snow storms. With wet pavement, it's hard to see the holes. Even when perfectly dry, it's not that great.

-- Jay Beattie.


  #153  
Old March 15th 17, 08:45 PM posted to rec.bicycles.tech
James[_8_]
external usenet poster
 
Posts: 5,513
Default More About Lights

On 15/03/17 18:07, Jeff Liebermann wrote:
On Wed, 15 Mar 2017 16:45:57 +1100, James
wrote:

On 15/03/17 16:15, Jeff Liebermann wrote:
On Wed, 15 Mar 2017 15:14:56 +1100, James
wrote:

On 15/03/17 13:43, Jeff Liebermann wrote:
On Tue, 14 Mar 2017 07:54:26 -0700, Joerg
wrote:

On 2017-03-13 20:00, Jeff Liebermann wrote:
On Mon, 13 Mar 2017 12:38:07 -0700, Joerg
wrote:
55V at 500mA. This is encouraging.

That's 27.5 watts out of a 3 watt dynamo. I was impressed, until I
converted 136 km/hr and found that it was 84.5 mph. With a rocket
assisted bicycle, I might be able to do that.

Well, yeah, they just wanted to see where the limit is. I guess the
enameled copper wire inside would smoke out if you kept that speed for long.

Only the resistive part dissipates power in the wi
P = I^2 * R = 0.5^2 * 2 = 0.5 watts
So, it won't be the wire that gets hot. However, the cores in
saturation are going to get warm. Offhand, I don't know how to
calculate how hot.

Do you mean eddy currents in the core?

Nope. I meant hysteresis losses. Eddy currents do contribute to
losses by "bucking" the build up and collapse of the magnetic field,
but most of the heat is produced by hysteresis losses:
https://www.quora.com/What-is-hysteresis-loss-Where-does-the-loss-actually-occur
See an induction heater or stove for an extreme case of heat being
generated by eddy and hysteresis currents:
https://en.wikipedia.org/wiki/Induction_heating


Hysteresis losses are different from saturation. Saturation shouldn't
occur if the core has been adequately designed to accommodate all the
permanent magnet flux & MMF.


Most (not all) dynamos are designed to provide some form of
self-regulation. This made sense back in the days when the load was
just a simple 6v incandescent light bulb. It wouldn't do to have
Kamakazi downhill speeders producing enough revolutions to have the
dynamo belch 12VAC and burn out the bulb.

Fast forward to today, and we no longer use incandescent lights on
dynamos. Most (not all) LED lamps have built in regulators and really
don't need to have the dynamo perform any additional regulation.
However, the industry is conservative, and things change very slowly.
Kinda like the automobile industry requiring 25 years to get rid of
the buggy whip socket. So, we still have dynamos that intentionally
designed to NOT produce a linear increase in output for high RPMs.

Fortunately, the problem is not universal.
http://www.pilom.com/BicycleElectronics/HubDynamo.htm
Notice the 2nd graph of Hub vs Bottle Power. The Shimano DH-3D71 hub
dynamo produces a linear increase in output power with no saturation
visible. (However, at my cruising speed of 15 km/hr, it only produces
4 watts and is therefore only a slight improvement over the common
bottle dynamo).

Hystersis loss is core saturation loss. What happens is that at some
point, adding additional current to the coil and core does produce an
increase in the magnetic field. Magnetic domains will change
direction when current is applied, but are not terribly thrilled with
the idea. Their resistance to this change in current and direction is
hysteresis loss. This additional current (and power) has to go
somewhere since it can't be used to build a changing magnetic field.
So, it gets converted into heat.

Eddy current losses are the result of changes in magnetic field, not
changes in applied current. When the magnetic field finally decides
to change direction and AFTER hysteresis losses are produced, the
resultant magnetic field breaks up into small magnetic loops or eddys.
Adjacent eddys fight each other resulting in repulsion. The energy
required to overcome this repulsive force are the eddy current losses.

As I understand it, the favored core material is some form of mu-metal
or permalloy which saturate nicely at low currents:
https://en.wikipedia.org/wiki/Mu-metal
I'm not sure this is the material as some description suggest that
it's "cold rolled dynamo silicon sheet steel" or the same stuff used
in the E/I laminations of a common AC power transformer.

It's after midnight. I give up for tonite.


You seem to be confusing current and magnetic flux.

What is used to alter the characteristics is the inductance of the
alternator coil.

--
JS

  #154  
Old March 15th 17, 09:40 PM posted to rec.bicycles.tech
James[_8_]
external usenet poster
 
Posts: 5,513
Default More About Lights

On 16/03/17 03:45, jbeattie wrote:
On Wednesday, March 15, 2017 at 7:53:52 AM UTC-7, David Scheidt
wrote:
Sir Ridesalot wrote:

:I remember burning out bulbs with my bottle dynamo if I rode
really :fast. I also remember the slipping problems when the wheels
were wet even :when I used the rubber boot sold to go on the bottle
dynamo roller. Hub :dynamos today really seem to fall down at slow
speeds.

Mine work fine from walking speeds. They produce more light at
higher speeds, but at slow speeds you don't need it, because you're
not moving fast.


I sometimes need light most at slow speeds, when I'm creeping up
hills and trying not to fall into giant pot holes.


You are an anomaly.

At creeping speeds (less than 10km/h), I could see holes with a candle
light.

--
JS
  #155  
Old March 15th 17, 10:17 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 4,414
Default More About Lights

On 3/15/2017 4:45 PM, James wrote:
On 15/03/17 18:07, Jeff Liebermann wrote:
On Wed, 15 Mar 2017 16:45:57 +1100, James
wrote:

On 15/03/17 16:15, Jeff Liebermann wrote:
On Wed, 15 Mar 2017 15:14:56 +1100, James
wrote:

On 15/03/17 13:43, Jeff Liebermann wrote:
On Tue, 14 Mar 2017 07:54:26 -0700, Joerg

wrote:

On 2017-03-13 20:00, Jeff Liebermann wrote:
On Mon, 13 Mar 2017 12:38:07 -0700, Joerg

wrote:
55V at 500mA. This is encouraging.

That's 27.5 watts out of a 3 watt dynamo. I was impressed, until I
converted 136 km/hr and found that it was 84.5 mph. With a rocket
assisted bicycle, I might be able to do that.

Well, yeah, they just wanted to see where the limit is. I guess the
enameled copper wire inside would smoke out if you kept that
speed for long.

Only the resistive part dissipates power in the wi
P = I^2 * R = 0.5^2 * 2 = 0.5 watts
So, it won't be the wire that gets hot. However, the cores in
saturation are going to get warm. Offhand, I don't know how to
calculate how hot.

Do you mean eddy currents in the core?

Nope. I meant hysteresis losses. Eddy currents do contribute to
losses by "bucking" the build up and collapse of the magnetic field,
but most of the heat is produced by hysteresis losses:
https://www.quora.com/What-is-hysteresis-loss-Where-does-the-loss-actually-occur

See an induction heater or stove for an extreme case of heat being
generated by eddy and hysteresis currents:
https://en.wikipedia.org/wiki/Induction_heating


Hysteresis losses are different from saturation. Saturation shouldn't
occur if the core has been adequately designed to accommodate all the
permanent magnet flux & MMF.


Most (not all) dynamos are designed to provide some form of
self-regulation. This made sense back in the days when the load was
just a simple 6v incandescent light bulb. It wouldn't do to have
Kamakazi downhill speeders producing enough revolutions to have the
dynamo belch 12VAC and burn out the bulb.

Fast forward to today, and we no longer use incandescent lights on
dynamos. Most (not all) LED lamps have built in regulators and really
don't need to have the dynamo perform any additional regulation.
However, the industry is conservative, and things change very slowly.
Kinda like the automobile industry requiring 25 years to get rid of
the buggy whip socket. So, we still have dynamos that intentionally
designed to NOT produce a linear increase in output for high RPMs.

Fortunately, the problem is not universal.
http://www.pilom.com/BicycleElectronics/HubDynamo.htm
Notice the 2nd graph of Hub vs Bottle Power. The Shimano DH-3D71 hub
dynamo produces a linear increase in output power with no saturation
visible. (However, at my cruising speed of 15 km/hr, it only produces
4 watts and is therefore only a slight improvement over the common
bottle dynamo).

Hystersis loss is core saturation loss. What happens is that at some
point, adding additional current to the coil and core does produce an
increase in the magnetic field. Magnetic domains will change
direction when current is applied, but are not terribly thrilled with
the idea. Their resistance to this change in current and direction is
hysteresis loss. This additional current (and power) has to go
somewhere since it can't be used to build a changing magnetic field.
So, it gets converted into heat.

Eddy current losses are the result of changes in magnetic field, not
changes in applied current. When the magnetic field finally decides
to change direction and AFTER hysteresis losses are produced, the
resultant magnetic field breaks up into small magnetic loops or eddys.
Adjacent eddys fight each other resulting in repulsion. The energy
required to overcome this repulsive force are the eddy current losses.

As I understand it, the favored core material is some form of mu-metal
or permalloy which saturate nicely at low currents:
https://en.wikipedia.org/wiki/Mu-metal
I'm not sure this is the material as some description suggest that
it's "cold rolled dynamo silicon sheet steel" or the same stuff used
in the E/I laminations of a common AC power transformer.

It's after midnight. I give up for tonite.


You seem to be confusing current and magnetic flux.

What is used to alter the characteristics is the inductance of the
alternator coil.


That's how I've seen it explained, with appropriate equations. Since AC
frequency increases with speed, the inductive reactance due to the coils
increases with speed. That fights the tendency for more voltage from
higher magnet-to-coil velocity.


--
- Frank Krygowski
  #156  
Old March 16th 17, 12:39 AM posted to rec.bicycles.tech
John B.[_3_]
external usenet poster
 
Posts: 2,121
Default More About Lights

On Wed, 15 Mar 2017 14:08:44 -0400, Frank Krygowski
wrote:

On 3/14/2017 11:15 PM, Jeff Liebermann wrote:
On Tue, 14 Mar 2017 12:09:27 -0400, Frank Krygowski
wrote:
But the point I was discussing was whether too brief or too dim
standlights really kill or seriously injure _stationary_ bicyclists.
I've never heard of such a case. I think it's yet another exaggerated
danger.


Bicycle lighting seems to be divided into "see where your going" and
"be seen" parts. Standlights are in the "be seen" part. If so, then
using a relatively narrow forward facing headlight is inadequate and a
poor substitute for all around "be seen" type lighting.

So far, no driver has tried to kill me while I'm stationary, but it's
possible. To help prevent such a threat, I would need all around
illumination because I don't know from what direction the driver might
approach and I do NOT need to see where I'm going (because I'm not
going anywhere). Some kind of flashing headband, flashing arm bands,
or maybe downward facing flood lights to illuminate an area. Maybe an
LED illuminated vest, which is now popular among highway workers:
https://www.amazon.com/HIGH-VISIBILITY-VEST-COMPLIANT-REFLECTIVE/dp/B01L2US0EY
https://www.amazon.com/SE-EP08L-Illuminated-Flashing-Feature/dp/B008WAE2XQ
https://www.amazon.com/SE-EP07L-Flashing-Illuminated-Safety/dp/B004J663A2
I don't know which type of "be seen" lighting might be most effective,
but any of the aformentioned would be better than a dim forward facing
standlight.


Thing is, nobody's demonstrated any need for so much stationary "be
seen" light, beyond the usual "well, it _could_ happen" safety inflation
mentality.

We're facing the same mentality regarding our local forest preserve.
Some people want to cut down every dead or dying tree within 100 feet of
any trail because, well, it _could_ fall on somebody and kill them. Sheesh.


I have worked in area where it is probable that no one has ever cut
down a tree until we arrived and there never was a problem with dead
or diseased trees falling down.

One problem with cutting down trees that "could" fall down is that in
a hurricane many perfectly healthy trees get blown down. Perhaps the
cutting of all trees taller than the average human "could" lives.

And, of course, banning the ownership of bicycles "could" save ~900
lives a year.
--
Cheers,

John B.

  #157  
Old March 16th 17, 12:46 AM posted to rec.bicycles.tech
AMuzi
external usenet poster
 
Posts: 8,261
Default More About Lights

On 3/15/2017 7:39 PM, John B. wrote:
On Wed, 15 Mar 2017 14:08:44 -0400, Frank Krygowski
wrote:

On 3/14/2017 11:15 PM, Jeff Liebermann wrote:
On Tue, 14 Mar 2017 12:09:27 -0400, Frank Krygowski
wrote:
But the point I was discussing was whether too brief or too dim
standlights really kill or seriously injure _stationary_ bicyclists.
I've never heard of such a case. I think it's yet another exaggerated
danger.

Bicycle lighting seems to be divided into "see where your going" and
"be seen" parts. Standlights are in the "be seen" part. If so, then
using a relatively narrow forward facing headlight is inadequate and a
poor substitute for all around "be seen" type lighting.

So far, no driver has tried to kill me while I'm stationary, but it's
possible. To help prevent such a threat, I would need all around
illumination because I don't know from what direction the driver might
approach and I do NOT need to see where I'm going (because I'm not
going anywhere). Some kind of flashing headband, flashing arm bands,
or maybe downward facing flood lights to illuminate an area. Maybe an
LED illuminated vest, which is now popular among highway workers:
https://www.amazon.com/HIGH-VISIBILITY-VEST-COMPLIANT-REFLECTIVE/dp/B01L2US0EY
https://www.amazon.com/SE-EP08L-Illuminated-Flashing-Feature/dp/B008WAE2XQ
https://www.amazon.com/SE-EP07L-Flashing-Illuminated-Safety/dp/B004J663A2
I don't know which type of "be seen" lighting might be most effective,
but any of the aformentioned would be better than a dim forward facing
standlight.


Thing is, nobody's demonstrated any need for so much stationary "be
seen" light, beyond the usual "well, it _could_ happen" safety inflation
mentality.

We're facing the same mentality regarding our local forest preserve.
Some people want to cut down every dead or dying tree within 100 feet of
any trail because, well, it _could_ fall on somebody and kill them. Sheesh.


I have worked in area where it is probable that no one has ever cut
down a tree until we arrived and there never was a problem with dead
or diseased trees falling down.

One problem with cutting down trees that "could" fall down is that in
a hurricane many perfectly healthy trees get blown down. Perhaps the
cutting of all trees taller than the average human "could" lives.

And, of course, banning the ownership of bicycles "could" save ~900
lives a year.



A bicycle ban?
How's that 100-year worldwide Heroin ban working?

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


  #158  
Old March 16th 17, 03:05 AM posted to rec.bicycles.tech
John B.[_3_]
external usenet poster
 
Posts: 2,121
Default More About Lights

On Wed, 15 Mar 2017 19:46:28 -0500, AMuzi wrote:

On 3/15/2017 7:39 PM, John B. wrote:
On Wed, 15 Mar 2017 14:08:44 -0400, Frank Krygowski
wrote:

On 3/14/2017 11:15 PM, Jeff Liebermann wrote:
On Tue, 14 Mar 2017 12:09:27 -0400, Frank Krygowski
wrote:
But the point I was discussing was whether too brief or too dim
standlights really kill or seriously injure _stationary_ bicyclists.
I've never heard of such a case. I think it's yet another exaggerated
danger.

Bicycle lighting seems to be divided into "see where your going" and
"be seen" parts. Standlights are in the "be seen" part. If so, then
using a relatively narrow forward facing headlight is inadequate and a
poor substitute for all around "be seen" type lighting.

So far, no driver has tried to kill me while I'm stationary, but it's
possible. To help prevent such a threat, I would need all around
illumination because I don't know from what direction the driver might
approach and I do NOT need to see where I'm going (because I'm not
going anywhere). Some kind of flashing headband, flashing arm bands,
or maybe downward facing flood lights to illuminate an area. Maybe an
LED illuminated vest, which is now popular among highway workers:
https://www.amazon.com/HIGH-VISIBILITY-VEST-COMPLIANT-REFLECTIVE/dp/B01L2US0EY
https://www.amazon.com/SE-EP08L-Illuminated-Flashing-Feature/dp/B008WAE2XQ
https://www.amazon.com/SE-EP07L-Flashing-Illuminated-Safety/dp/B004J663A2
I don't know which type of "be seen" lighting might be most effective,
but any of the aformentioned would be better than a dim forward facing
standlight.

Thing is, nobody's demonstrated any need for so much stationary "be
seen" light, beyond the usual "well, it _could_ happen" safety inflation
mentality.

We're facing the same mentality regarding our local forest preserve.
Some people want to cut down every dead or dying tree within 100 feet of
any trail because, well, it _could_ fall on somebody and kill them. Sheesh.


I have worked in area where it is probable that no one has ever cut
down a tree until we arrived and there never was a problem with dead
or diseased trees falling down.

One problem with cutting down trees that "could" fall down is that in
a hurricane many perfectly healthy trees get blown down. Perhaps the
cutting of all trees taller than the average human "could" lives.

And, of course, banning the ownership of bicycles "could" save ~900
lives a year.



A bicycle ban?
How's that 100-year worldwide Heroin ban working?


Works great! Allows a considerable number of common ordinary people to
make a "decent" living.

True the demand does seems to be decreasing but the widening the
demand for amphetamines, which can be made at home rather than waiting
for a crop to ripen and getting all bound up with buying futures and
warehousing raw materials.

As an aside, do you think anyone wants the "war on drugs" to be won?

Examples:

U.S. Coastguard budget (numbers adjusted to 2013 dollars):
1950 - $1,439,312,446
2013 - $ 7,051,054,000

The total DEA budget is difficult to ascertain but:
The total budget of the DEA from 1972 to 2014, according to the
agency website, was $50.6 billion. The agency had 11,055 employees in
2014. For the year 2014 the average cost per arrest made was $97,325.

An estimate by The Cato Institute, in 2010, states that the legalizing
of drugs would save roughly $41.3 billion per year in government
expenditure. Or to put it a different way, The War on Drugs is costing
the U.S. an estimated $41.3 billion dollars a year.

Do you think that anyone wants all that lovely lolly to disappear?
--
Cheers,

John B.

  #159  
Old March 16th 17, 04:12 AM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 4,414
Default More About Lights

On 3/15/2017 11:05 PM, John B. wrote:
On Wed, 15 Mar 2017 19:46:28 -0500, AMuzi wrote:

On 3/15/2017 7:39 PM, John B. wrote:
On Wed, 15 Mar 2017 14:08:44 -0400, Frank Krygowski
wrote:

On 3/14/2017 11:15 PM, Jeff Liebermann wrote:
On Tue, 14 Mar 2017 12:09:27 -0400, Frank Krygowski
wrote:
But the point I was discussing was whether too brief or too dim
standlights really kill or seriously injure _stationary_ bicyclists.
I've never heard of such a case. I think it's yet another exaggerated
danger.

Bicycle lighting seems to be divided into "see where your going" and
"be seen" parts. Standlights are in the "be seen" part. If so, then
using a relatively narrow forward facing headlight is inadequate and a
poor substitute for all around "be seen" type lighting.

So far, no driver has tried to kill me while I'm stationary, but it's
possible. To help prevent such a threat, I would need all around
illumination because I don't know from what direction the driver might
approach and I do NOT need to see where I'm going (because I'm not
going anywhere). Some kind of flashing headband, flashing arm bands,
or maybe downward facing flood lights to illuminate an area. Maybe an
LED illuminated vest, which is now popular among highway workers:
https://www.amazon.com/HIGH-VISIBILITY-VEST-COMPLIANT-REFLECTIVE/dp/B01L2US0EY
https://www.amazon.com/SE-EP08L-Illuminated-Flashing-Feature/dp/B008WAE2XQ
https://www.amazon.com/SE-EP07L-Flashing-Illuminated-Safety/dp/B004J663A2
I don't know which type of "be seen" lighting might be most effective,
but any of the aformentioned would be better than a dim forward facing
standlight.

Thing is, nobody's demonstrated any need for so much stationary "be
seen" light, beyond the usual "well, it _could_ happen" safety inflation
mentality.

We're facing the same mentality regarding our local forest preserve.
Some people want to cut down every dead or dying tree within 100 feet of
any trail because, well, it _could_ fall on somebody and kill them. Sheesh.

I have worked in area where it is probable that no one has ever cut
down a tree until we arrived and there never was a problem with dead
or diseased trees falling down.

One problem with cutting down trees that "could" fall down is that in
a hurricane many perfectly healthy trees get blown down. Perhaps the
cutting of all trees taller than the average human "could" lives.

And, of course, banning the ownership of bicycles "could" save ~900
lives a year.



A bicycle ban?
How's that 100-year worldwide Heroin ban working?


Works great! Allows a considerable number of common ordinary people to
make a "decent" living.

True the demand does seems to be decreasing but the widening the
demand for amphetamines, which can be made at home rather than waiting
for a crop to ripen and getting all bound up with buying futures and
warehousing raw materials.

As an aside, do you think anyone wants the "war on drugs" to be won?

Examples:

U.S. Coastguard budget (numbers adjusted to 2013 dollars):
1950 - $1,439,312,446
2013 - $ 7,051,054,000

The total DEA budget is difficult to ascertain but:
The total budget of the DEA from 1972 to 2014, according to the
agency website, was $50.6 billion. The agency had 11,055 employees in
2014. For the year 2014 the average cost per arrest made was $97,325.

An estimate by The Cato Institute, in 2010, states that the legalizing
of drugs would save roughly $41.3 billion per year in government
expenditure. Or to put it a different way, The War on Drugs is costing
the U.S. an estimated $41.3 billion dollars a year.

Do you think that anyone wants all that lovely lolly to disappear?


To make a sort of meta-point:

People often claim that the discussions here are worthless. In
particular, because nobody here ever changes their mind.

But it's partly because of information I've gotten here (corroborated
elsewhere) that I now believe most drugs should be legalized. I think
the U.S. should more or less follow the Portugal strategy, with perhaps
some minor modifications.

--
- Frank Krygowski
  #160  
Old March 16th 17, 05:44 AM posted to rec.bicycles.tech
Sir Ridesalot
external usenet poster
 
Posts: 3,306
Default More About Lights

On Wednesday, March 15, 2017 at 5:40:55 PM UTC-4, James wrote:
On 16/03/17 03:45, jbeattie wrote:
On Wednesday, March 15, 2017 at 7:53:52 AM UTC-7, David Scheidt
wrote:
Sir Ridesalot wrote:

:I remember burning out bulbs with my bottle dynamo if I rode
really :fast. I also remember the slipping problems when the wheels
were wet even :when I used the rubber boot sold to go on the bottle
dynamo roller. Hub :dynamos today really seem to fall down at slow
speeds.

Mine work fine from walking speeds. They produce more light at
higher speeds, but at slow speeds you don't need it, because you're
not moving fast.


I sometimes need light most at slow speeds, when I'm creeping up
hills and trying not to fall into giant pot holes.


You are an anomaly.

At creeping speeds (less than 10km/h), I could see holes with a candle
light.

--
JS


Must be nice to be blessed with such perfect vision! many of us find that we need a prety bright light in order to see where we're going and the obstacles to avoid at night. that's not to mention that it's nice to be able to see critters on theroads or trails in time to slow or stop to avoid running over them. Personally, I like a supplemental High beam light so that ican see a longer way down an unlit very dark road on a moonless night so I can see the skunks at the side of the road or on the road well BEFORE I startle them. YMMV

Cheers
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Dynamo Lights viz Battery Lights in snow qand slush? Sir Ridesalot Techniques 6 March 4th 15 10:36 PM
No lights, dark clothing, no reflectives, no street lights. Mrcheerful UK 153 November 4th 14 09:19 AM
Maybe it's safer to run red lights than to wait for green lights. SMS General 16 September 24th 08 09:51 PM
Light Theft (solutions — small pocket lights, or heavy duty well secured lights?) David Johnson UK 24 August 29th 07 02:32 PM
Break lights turn lights and handle bar lights Truepurple Techniques 30 November 17th 03 04:02 AM


All times are GMT +1. The time now is 08:36 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright 2004-2017 CycleBanter.com.
The comments are property of their posters.