Cheap bright tail light

On 9/1/2014 10:44 PM, David Scheidt wrote:
Frank Krygowski wrote:
:On 9/1/2014 2:44 PM, David Scheidt wrote:
: Frank Krygowski wrote:
: :On 9/1/2014 1:53 PM, David Scheidt wrote:
: : Frank Krygowski wrote:
: : :On 9/1/2014 3:28 AM, Phil W Lee wrote:
: : : Remember that all of the
: : : light a red LED produces is already red, so it doesn't have it's light
: : : output reduced to between 25 and 40% of what comes out of the filament
: : : bulb by putting it straight through a filter. So you are already 250
: : : to 400% up on a filament, even without any efficiency gain at all.
: : : Multiply that by the efficiency gain, and you can have something very
: : : bright for a power budget that is very low.
: :
: : :To vouch for that:
: :
: : :I was given some very high output LEDs by an engineer friend who works
: : :for a company producing architectural LED products. I used two of the
: : :red LEDs to upgrade incandescent taillights on two bikes.
: :
: : :After observing them in the dark, I decided to point both taillights
: : :downward a bit, below horizontal. I was afraid that otherwise, the
: : :glare would be too much for oncoming motorists - not to mention any
: : :bicyclists that might be following me.
: :
: : Which is a big clue you don't have the optics right.
:
: :I suppose you could say that. I barely succeeded in cramming LED, heat
: :sink, etc. into the old taillight housings. There was no way to work on
: ptics. But really, the beam pattern requirements for a taillight are
: retty minimal. That's one place a Scharfian fog of light actually works.
:
: No, not really. While the pattern isn't as defined as for a
: headlight, there's little point putting light somewhere it's not going
: to be seen.

:I agree in principle, but as in so many things, there's a
:benefit-vs-detriment consideration. The LEDs that were given to me are
:extremely bright. I didn't get specs with them, but I doubt the rear
ne was consuming 1 Watt before I put the resistors in series on the one
:bike, to dim it down. How much effort is appropriate to a) reduce the
:light output from a free LED and also b) direct the reduced number of
:lumens in exactly the proper direction? IMO, the answer is "Not much."

:Now if I were designing a commercial taillight, I suppose I might judge
:the effort to be worthwhile.

I'm riding a bike, on roads with other people. My goal with a taillight
is "not get killed". Doing it right, with good quality comerical light
cost $40. If you value your time at minumum wage, you're likely to have
more than that in your defective light. (Big clue: you have parts
whose only purpose is to waste part of your very small power budget.)

I say that, and I like making things, including things that make zero
eonomic sense. Bike lights are just not worth
my time: good examples are readily available, cheap enough, and work
btter than anything I can come up with.

The cool thing about being retired (and being lucky enough to get decent
retirement checks) is that I get to spend my time on what's interesting
to me. Sure, I could pay $40 and get a good taillight. And I could
spend, oh, $800 and get a "city bike" that's as good as my 3-speed
"retro-tech" project, the one built almost entirely out of stuff I
already had. But I wouldn't have had as much fun, and I wouldn't have
learned as much.

Oh, and "not get killed" isn't high on my list of objectives! Why?
Because I know from national data, plus from observations and tests that
I've run with other folks, that getting killed on my bike is
fantastically unlikely. Things are just not that bad out there, despite
all the propaganda. "Not get killed on a bike" ranks with "Not get
killed by accidentally inhaling poisonous gas."

And one doesn't need SuperBlinderLights to be adequately safe - again,
despite all the propaganda. Get a friend to help you test your bike.
If you've done a halfway competent job with lights and reflective bits,
you'll see.

--
- Frank Krygowski

Phil W Lee wrote:
Joerg considered Sun, 31 Aug 2014
13:43:49 -0700 the perfect time to write:

Phil W Lee wrote:
Joerg considered Fri, 29 Aug 2014
17:37:38 -0700 the perfect time to write:

Frank Krygowski wrote:
On 8/29/2014 7:01 PM, Joerg wrote:
Frank Krygowski wrote:
The problem is that (at least in the U.S.) few people ride at night.
People think it's hideously dangerous. And of course they all have
cars. So the market is small.

And most of those who do ride at night tend to do it pretty rarely, only
in near-ideal conditions, because they're doing it only for fun. So
they tend to be pretty easy on their equipment. If it lasts only 50
hours, they'll get perhaps ten years use out of it.

That is because hardly anyone commutes anymore which is sad.
Oh, but that's not true! Everyone knows that bike use is surging! Why,
as this article states,
http://www.slate.com/blogs/the_slate...t_popular.html

"Bicycle Commuting Rates Rocket From 0.5 Percent to 0.6 Percent in Only
32 Years!"

According to the League of American Bicyclist's usual modus operandi,
that should be trumpeted as a 20% increase!!! ;-)

:-)

But I do have to say that since they started putting in more bike paths
and bike lanes it has picked up more than that here in the last 7-8
years. To the point where new bike dealers are opening while until 2005
they were dying left and right.

I also see some more longhaul commuters in road bikes.

What is sad is that some beautiful trails out here are barely used. When
I see another montain biker there we great each other enthusiastically
because that happens maybe once a month and I ride them 2-3 times a week.

I don't find it all that surprising that few people commute on
mountain bike trails, particularly ones which (by your own evidence)
are so brutal on the bike.

But they are fun :-)


Serious
commuting means including winter and then one or both trips will require
lights. So 50 hours would be gone in a month or two. I run through
batteries as if it was popcorn. Environmentally not so cool. Luckily the
front one on the MTB is Li-Ion but one of them already starts to fade.
Yep. Another couple reasons to love generators or dynamos. They last
damned near forever, and low temperatures don't bother them.

Only as long as there is also a sizeable rechargeable battery.

Sizeable enough for the whole half hour that you are moving slow
enough to need it?

With a dynamo, yes. But ...


I'm sure it wouldn't be hard to bleed off the spare power when you are
going over 15kmh to recharge it ready for the next hill.
You need to rectify it for an LED anyway.
It's so easy that B&M have already done it - the Ixon IQ has a pack of
four NiMH AAs and a charge socket on the bottom, into which you can
plug the ride & charge cable from a hub dynamo.
That would give you 5 hours of use at full power without any input
from the dynamo at all, and any time you are doing more than 15kmh,
it's charging, even with the light on full power.

That is good, four NiMH are ok. However, dynamos pretty much zonk out
around 4-5W. If you want a 2W tail light (and I do) and in order to see
enough trail a 5-10W front light, that's going to be a challenge. So
I'll be going the Li-Ion route and no dynamo, or maybe a small bottle
dynamo for emergency like I have on the road bike.


Also, regarding one of your specific complaints, most people don't see a
need to run wires from a central battery to a taillight. AA or AAA
batteries in taillights last a long, long time and are easy to buy and
change.

You cannot get any serious light out of AAA and that's all you normally
find. A 2W LED will suck AAA dry in very few hours.
Do you really need 2 Watts into a rear red LED?
Oh yeah.
Why?
In Germany it is standardised on 0.6w even for filament bulbs, and
they don't seem to have any serious problems with rear-end collisions.

They do. One of my former class mates ended up losing a kidney, the
other landed in the hospital with a ruptured spleen. And I personally
witnessed a side swipe accident in Germany. But I live in the US so I am
not bound by this stupid 3W total dynamo power law.

You can have 6w right now, and fully legal in all respects.
Any approved dynamo ( 3w or 6w) is tested to that power under lab
conditions, which don't take account of the wonderful nature of LEDs
driven by constant current devices - even a standard 3w dynamo will
power two of those German standard lights in series at over 15kmh.
And of course, if your dipped beam is an Ixon, ...


Nice light but on my usual trails which I often also use to get from A
to B it would not likely last more than a month:

http://www.peterwhitecycles.com/b&m.asp

Anything that isn't similar to aircraft aluminum tends to break rather
quickly. I had lights that didn't even survive their first ride.


... you can re-purpose that
generator output to a high beam while leaving the Ixon on battery
power - giving anything up to 6w available for your high beam alone
(on a 3w generator - double that for a 6w one, although that won't
drive the Ixon charge circuit (which doesn't need to overlap the areas
covered by the Ixon, either).


6W could (though barely) be enough for high-beam on a trail.


Regardless of your opinion on the value of eyeball searing rear lights
on the roads, I take it you accept that off road a relative glow-worm
is acceptable, which means (in terms of LEDs), that the power
consumption can be more or less ignored.


Yes, on the trail all I need is a flashing rear light that can be
detected by night-sight gear. Just in case I screw up badly. Which I
almost did about 10 days ago before my flight to Germany. A Manzanita
branch grabbed my hydration pack and yanked me off the mountain bike at
a clip of 20mph. My bad, I was in a rush and should have slowed down.


... Remember that all of the
light a red LED produces is already red, so it doesn't have it's light
output reduced to between 25 and 40% of what comes out of the filament
bulb by putting it straight through a filter. So you are already 250
to 400% up on a filament, even without any efficiency gain at all.
Multiply that by the efficiency gain, and you can have something very
bright for a power budget that is very low.
LED rear lights are used with 3w front lights, incandescent rear
lights (0.6w) are paired with 2.4w front lights. so LED power
consumption disappears in the noise and variation that is inherent in
any variable speed production system produced to a low budget - as
it's less than the variation in generator output.


If I have to build my own LED light I'd rather go for 10W in front and
at least 1W in back, preferably 2W. Then the lights will compete with
motor vehicle lights and the front light wold become very useful on
trails, or I could ride faster on trails at night.

I was just in Germany and saw some of their modern bike lights. Not
super impressive when it comes to light output but ok for non-trail
usage. However, they were plastic and that stuff doesn't last with my
kind of riding.


Mind you, the design is fairly tightly controlled, so light output is
well distributed in the areas where it is needed, instead of projected
down a narrow beam.

Well, in the bush you need a bit more, including a good overhead
illumination to spot branches that could snap your helmet. On the road
I'd turn that off. Some lights have that feature but it's often
implemented crudely via 3-4 LEDs instead of just one, and so far I only
found cheap Chinese lights like that. Possibly I'll have to buy one and
try to ruggedize it like I did with my current light.

So something like an E3 for high beam and any of the current crop of
good German approved front lights as a low beam.


If they had sturdy metal ones which are also somewhat crashworthy. The
Magnus light I have right now survived a nasty one around 10 days ago.
Things got scraped up a bit (including myself) and I am very sure a
plastic light would have come home in a bag, in pieces.

[...]

--
Regards, Joerg

http://www.analogconsultants.com/

Jeff Liebermann wrote:
On Sun, 31 Aug 2014 14:00:38 -0700, Joerg
wrote:

Works with bulbs but LEDs have very narrow spectral bands. I've tried a
red filter in front of my fairly powerful LED front light and it made it
rather dim.

I'm surprised that you saw anything through the red lens. It doesn't
work because, unlike an incandescent lamp, the light from a typical
phosphor LED is not uniformly spread across the visible spectrum.
There are some rather sharp peaks at various colors. For example:
http://en.wikipedia.org/wiki/Light-emitting_diode#Phosphor-based_LEDs
Note the graph of the spectra. A red LED filter would peak at about
635nm. There's almost no output at that wavelength on the white LED
spectrum.


They often use conversion phosphors but a white LED will not be
efficient at all in this mode. It was just a test. On a mountain bike
you can't have a long big light in back anyhow. It has to be compact and
withstand the occasional Chapparal or Manzanita branches shredding
through the rear wheel and smacking into the light. Which is why
anything palstic just isn't good enough. Currently I have two
aluminum-body lights back there but they aren't super bright.

--
Regards, Joerg

http://www.analogconsultants.com/

James wrote:
On 01/09/14 08:34, Joerg wrote:
James wrote:


My rear light is on the seat post and not far above the frame. I can
easily see the light is flashing at night. During twilight I put my
hand behind the light and see the light on my hand while I'm riding.

https://www.flickr.com/photos/55102679@N05/14948765991


I had one like that on my MTB. It lasted about half a ride.

Someone gave me that tail light well over 15 years ago, and it has
_never_ failed. I use it at least 3 nights a week for 2 hour rides.
It's been on my MTB as well.


Depends on how and where you ride. I just put a major gash into the side
of a $50 tire. It needs to be replaced. Darn.


Now I have
this kind but two of them because there is no low-batt warning and you
can't see them by bending over:

http://www.amazon.com/LIFETIME-GUARA...nus+Innovation



I can turn mine on and off while riding. It's not difficult to put my
hand behind and look to see the light flashing on my hand.

I usually check the light before I go out and keep a stock of cheap AA
batteries at home. I think just once I bought a couple of AA batteries
from a service station because the light was getting a bit weak after
the first hour of riding.


It's ok but I'd still like a brighter light. Portland Works has one but
it's plastic.

--
Regards, Joerg

http://www.analogconsultants.com/

Phil W Lee wrote:
Joerg considered Sun, 31 Aug 2014
14:02:58 -0700 the perfect time to write:

Phil W Lee wrote:
Joerg considered Sat, 30 Aug 2014
09:39:24 -0700 the perfect time to write:

Sir Ridesalot wrote:
[...]

Many AA or AAA tail lights are quite bright especially on trails and
some are too bright for a following rider.

But you never know when they run out of juice because the manufacturer's
engineers can't get it into their heads that there should be a charge
level indicator. Technically a piece of cake, you measure the voltage
sag upon pulsing and when that exceeds the 80% or whatever discharge
mark let the light flash a bit more irregular than usual. Then the rider
would still have time to get homes safely but would know that a fresh
set of batteries or a Li-Ion recharge is required soon. When do they
wake up?
They have.
Bettery level indicators are so common that they've made them a
mandatory requirement (on those few bikes where it's legal to not have
a dynamo system) in Germany.

For the rear light? So why are all those sold over here in the US sans
low-batt warning? Including expensive ones.

Only on the front.
But if you look after your batteries, carry spares, and have redundant
lights (I go for one flashing and one solidly on, as a minimum) you
shouldn't have a problem since battery drain is so low on a rear
light.


I always have tqwo independent tail lights because aside from batteries
one could vibrate itself inoperable on a gnarly trail section.


You can easily make (as Frank suggested) a fibre-optic tell-tale if
your rear light(s) are mounted too far back to be able to see.
Interestingly, the British Standard stipulates that a small portion of
the light should be visible forward and upward from the lighting unit,
for exactly the same purpose.


If I ever get around to making my own electric system for the bike it'll
have sensors and an alert for that. Pretty easy to do if using a 3rd
wire to the lights.

--
Regards, Joerg

http://www.analogconsultants.com/

Am 13.09.2014 00:34, schrieb Joerg:

I was just in Germany and saw some of their modern bike lights. Not
super impressive when it comes to light output but ok for non-trail
usage. However, they were plastic and that stuff doesn't last with my
kind of riding.

So something like an E3 for high beam and any of the current crop of
good German approved front lights as a low beam.

If they had sturdy metal ones which are also somewhat crashworthy. The
Magnus light I have right now survived a nasty one around 10 days ago.
Things got scraped up a bit (including myself) and I am very sure a
plastic light would have come home in a bag, in pieces.

The good German approved front lights do exist in sturdy metal
http://www.nabendynamo.de/, they are just a bit more expensive.

Rolf

On 9/12/2014 3:34 PM, Joerg wrote:

If they had sturdy metal ones which are also somewhat crashworthy. The
Magnus light I have right now survived a nasty one around 10 days ago.
Things got scraped up a bit (including myself) and I am very sure a
plastic light would have come home in a bag, in pieces.

There is an Edelux II with an aluminum body and a glass lens. Around
$200 in the U.S. (plus the cost of a mount).

There's also this one:
http://www.dx.com/p/3w-3-led-270-lumen-waterproof-flood-light-projection-warm-white-lamp-12v-47572
which works fine directly off of a hub dynamo. It has a better beam
shape than the Edelux II for night riding in the U.S. where you want a
more symmetrical beam in order to illuminate street signs and overhead
obstacles. It's gone way up in price since I bought one, but it's still
not bad at $16.39.

Cue the "Chinese lights" schtick!

On 9/15/2014 11:33 AM, SMS wrote:
On 9/12/2014 3:34 PM, Joerg wrote:

If they had sturdy metal ones which are also somewhat crashworthy. The
Magnus light I have right now survived a nasty one around 10 days ago.
Things got scraped up a bit (including myself) and I am very sure a
plastic light would have come home in a bag, in pieces.

There is an Edelux II with an aluminum body and a glass lens. Around
$200 in the U.S. (plus the cost of a mount).

There's also this one:
http://www.dx.com/p/3w-3-led-270-lumen-waterproof-flood-light-projection-warm-white-lamp-12v-47572
which works fine directly off of a hub dynamo. It has a better beam
shape than the Edelux II for night riding in the U.S. where you want a
more symmetrical beam in order to illuminate street signs and overhead
obstacles.

:-) I hope our European readers don't seriously believe Scharf's
implications that U.S. roads are places where vehicles must crash
through tree branches, and where people routinely get lost by not seeing
street signs at night!


--
- Frank Krygowski

Rolf Mantel wrote:
Am 13.09.2014 00:34, schrieb Joerg:

I was just in Germany and saw some of their modern bike lights. Not
super impressive when it comes to light output but ok for non-trail
usage. However, they were plastic and that stuff doesn't last with my
kind of riding.

So something like an E3 for high beam and any of the current crop of
good German approved front lights as a low beam.

If they had sturdy metal ones which are also somewhat crashworthy. The
Magnus light I have right now survived a nasty one around 10 days ago.
Things got scraped up a bit (including myself) and I am very sure a
plastic light would have come home in a bag, in pieces.

The good German approved front lights do exist in sturdy metal
http://www.nabendynamo.de/, they are just a bit more expensive.


$200, ouch. I think they offer a handlebar mount, probably costing an
arm and a leg. But that ring switch in the back isn't going to last on
mountain bike. You can't have any protrusions upward or on either side,
it's going to shear off.

After a Manzanita tree yanked me out of the saddle a couple weeks ago
and my bike continued its journey until it hit something and rolled over
(like I did), the light on my handlebar got royally scraped on top. But
.... still works.

However, I believe the Edelux II has only around 300 lumens and no
high-beam. Other than that it's a nice light but not very useful for
trail riding where you need a rounder beam pattern:

http://www.peterwhitecycles.com/edel...PWC08-02-4.pdf
http://www.peterwhitecycles.com/schmidt-headlights.asp

--
Regards, Joerg

http://www.analogconsultants.com/

Frank Krygowski wrote:
On 9/15/2014 11:33 AM, SMS wrote:
On 9/12/2014 3:34 PM, Joerg wrote:

If they had sturdy metal ones which are also somewhat crashworthy. The
Magnus light I have right now survived a nasty one around 10 days ago.
Things got scraped up a bit (including myself) and I am very sure a
plastic light would have come home in a bag, in pieces.

There is an Edelux II with an aluminum body and a glass lens. Around
$200 in the U.S. (plus the cost of a mount).

There's also this one:
http://www.dx.com/p/3w-3-led-270-lumen-waterproof-flood-light-projection-warm-white-lamp-12v-47572

which works fine directly off of a hub dynamo. It has a better beam
shape than the Edelux II for night riding in the U.S. where you want a
more symmetrical beam in order to illuminate street signs and overhead
obstacles.


Unfortunately that doesn't look like it would survive the first five
trail miles.

Amazon has some high-intensity (1000 lumen) lights. I wish someone
could point out which model(s) are super-rugged. Ok, and I really do not
want to spend $200 on a light that might get smashed during the next endo.


:-) I hope our European readers don't seriously believe Scharf's
implications that U.S. roads are places where vehicles must crash
through tree branches, and where people routinely get lost by not seeing
street signs at night!


In the bush you can easily break your neck if you don't see a branch
jutting out. After I got a new (thicker) helmet I misjudged branch
heights a couple of times and man, that really gives you a jolt in the
neck. It's a real danger.

About crashing through tree branches, some trails out here require that.
They are not well traveled and overgrow quickly. I took one of those a
bit fast a couple weeks ago. It got late and I stepped on it, whatever
my muscles could do. 15mph, 17mph, 19mph, 20mph ... *THWOCK* ... bike
disappeared from underneath me. A large Manzanita branch that I didn't
see in time grabbed a loop on my hydration pack.

http://analogconsultants.com/ng/bike/estavista4.JPG
http://analogconsultants.com/ng/bike/estavista5.JPG

Maybe now it also becomes clear why we need a somewhat circular
high-beam illumination at night out here. An innocently looking 1/2"
Manazanita branch would be capable of towing a truck and you really
don't want that to get in your face or, worse, snag your helmet with
your head being strapped into it.

--
Regards, Joerg

http://www.analogconsultants.com/