"white" LED's vs. incandescent and halogen lights

"white" LED's vs. incandescent and halogen lights

Post by Frank Krygowsk » Thu, 17 Dec 2009 13:39:05



Quote:




> >>>>> Or you could do what sensible people do and use a battery-powered
> >>>>> LED rear light, which, unlike a front light, will run for the
> >>>>> best part of a Randonneur Round The Year season on a pair of
> >>>>> AAAs.

> >>>> No argument there, but someone in this thread was trying to find
> >>>> an LED bulb for their rear dynamo powered light. The whole thing
> >>>> is ridiculous.

> >>> Nobody at all mentioned looking for a rear dynamo bulb! You
> >>> continue to astonish us.
> >> Of late, even dedicated dynamo aficionados run head only, very few
> >> wired tail lamps now. ?Once seen as a 'freebie' unit, ?LED blinkies
> >> (especially mounted high, on the rider) have made tail lamps more
> >> 'free and worth every penny'.

> >> Not advocating here, just reporting.

> > I don't think any of the riders I know with dynamos are using a wired
> > taillight, nor do I. ?The battery powered LEDs are good enough.

> I do, but simply because I'm lazy (same reason I went with a dynamo in
> the first place.) ?I like my bike to be just like a car, hop on and go.

I've also got a generator taillight in addition to my blinky on one
bike, for several reasons:

1) Redundancy.  (I've had a blinky lose its lens and batteries on a
bad bump.)

2) Experimentation.  My generator taillight is controlled by a switch
on the handlebars, so I can examine its effect on the brightness of my
halogen headlamp.  (It's noticeably brighter with the taillight off,
one reason a person might change to an LED taillight.)

3) It's there!  I have no motivation to take it off.

But all that applies only to my utility bike.  All my other bikes do
fine with battery-powered LED blinkies.

- Frank Krygowski

 
 
 

"white" LED's vs. incandescent and halogen lights

Post by SMS » Thu, 17 Dec 2009 13:48:05

Quote:




>>> AFAICT, the best deal going in the US is the prebuilt VO front wheel
>>> at about $120ish - I bought one.  Unfortunately, the CR18 rear wheels
>>> have been unavailable for months - I suspect that they may be
>>> discontinuing them? - so the screaming dealness of the front wheel was
>>> offset by the cost of having a rear wheel built at my LBS :(
>> LOL, so it's $60 was just for a hub dynamo without the wheel? How much
>> is a whole wheel? Peter White charges quite a bit for his custom wheels
>> with a dynohub, OTOH the VO wheel is a pretty good deal at $120,
>> "http://www.velo-orange.com/vopbprimwnoh.html." I'm going to pick one up
>> for my touring bike.

> But but but, I thought you just got through explaining how it's
> impossible to light up the road for safe riding with a generator
> light?

No, I never said that. I use dynamos all the time. Under certain
circumstance they are adequate.

"In well lit cities where the cyclist is familiar with their route, a
dynamo system is often sufficient. However due to the power generation
limits of a bicycle dynamo, it simply is not possible to generate enough
power for lights that are bright enough for use on dark or unfamiliar
routes. Another factor is that as we age, our night vision deteriorates,
and brighter lighting is necessary for safety."

 
 
 

"white" LED's vs. incandescent and halogen lights

Post by Frank Krygowsk » Thu, 17 Dec 2009 13:59:58


Quote:


> > >In any case, I don't think anyone's touched on the biggest reason why it
> > >isn't practical to do drop-in replacements of a 3W LED to replace a 3W
> > >filament bulb. The 3W LEDs generate a large amount of heat at the
> > >semiconductor junction, and require very good heat sinks.

> > Yes, it's well known that incandescent "bulbs" (lamps, Steven, they
> > are called lamps) emit no heat whatsoever.

> There is a critical difference. ?Incandescent bulbs radiate out most
> of their heat instead of retaining it in the device. ?And they are
> made of glass and metals that are relatively tolerant of high
> temperatures. ?An LED dumps all its heat within the semiconductor die,
> which can easily burn itself up if it does not have an adequate path
> through which to discharge waste heat.

That's true, and a very clear explanation.  However, bulbs have their
own thermal problems.  I've had incandescent headlights fail when I
installed more powerful bulbs, because the reflectors couldn't
withstand the increased heat load.  And I'm talking about modest
increases in bulb wattage.

There are drop-in replacement LED bulbs for flashlights, auto brake
lights, auto turn signal lights, and many other applications.  They
don't require elaborate heat sinks. The thermal problems are not
always difficult to solve.

- Frank Krygowski

 
 
 

"white" LED's vs. incandescent and halogen lights

Post by Frank Krygowsk » Thu, 17 Dec 2009 14:06:40


Quote:

> Sigh, trying to explain semiconductors, physics, and thermodynamics to
> people like Guy is not something you're going to be able to do on
> Usenet. You would need to dedicate your whole life the pursuit.

:-) That was stated by the guy who holds the record for technical
mistakes in these discussions!

I haven't visited our "world's greatest expert" websites recently.  I
wonder if he's yet corrected the "data" claiming that changing the
reflector increases a bulb's lumen output?

- Frank Krygowski

 
 
 

"white" LED's vs. incandescent and halogen lights

Post by Dan » Thu, 17 Dec 2009 14:25:16


Quote:


> >> Of late, even dedicated dynamo aficionados run head only, very few
> >> wired tail lamps now.  Once seen as a 'freebie' unit,  LED blinkies
> >> (especially mounted high, on the rider) have made tail lamps more
> >> 'free and worth every penny'.

> >> Not advocating here, just reporting.

> > I wish that the riders that are forgoing good headlights would at least
> > put a white LED blinkie on the front too. If they don't need to see
> > anything, at least they should be seen by drivers. Last week my wife
> > turned right in front of a cyclist and almost hit him on the street
> > perpendicular to ours. It was totally dark, he had no front light, and
> > after he went past she noticed a ***tore quality rear flasher. He gave
> > her the finger. She shook her head. His life was not even worth spending
> > $20 on a light.

> > Fortunately, riding without good lights seems to be the exception,
> > rather than the rule, in my area. Some cyclists are so well lit up with
> > so many blinkers, as well as a good battery-powered headlight, that it's
> > almost amusing to be behind them.

> > I need to get a 3W bulb for my dynamo powered headlight so I can drop
> > the tail lamp. It's a Union system and I don't think there's any
> > protection circuit in the headlight.

> Unfortunately IME riders like you mention above aren't an exception at
> all.  Used to be most of the riders I'd see after dark, although of late
> I have been seeing more and more riders riding with at least proper
> blinkies if not real headlights.  I guess the cold weather is weeding
> out the idiots?

... and the pussies ;-)
 
 
 

"white" LED's vs. incandescent and halogen lights

Post by Frank Krygowsk » Thu, 17 Dec 2009 14:48:21


Quote:

> "In well lit cities where the cyclist is familiar with their route, a
> dynamo system is often sufficient. However due to the power generation
> limits of a bicycle dynamo, it simply is not possible to generate enough
> power for lights that are bright enough for use on dark or unfamiliar
> routes. "

In other words, it is simply not possible to use generator lighting
for audax events, or rides like Paris-Brest-Paris.

Despite the fact that hundreds of competitors do so with perfect
success.  And despite the fact that a recent survey showed generator
users in P-B-P were more satisfied with their lights than those using
battery powered lights.

- Frank Krygowski

 
 
 

"white" LED's vs. incandescent and halogen lights

Post by Chal » Thu, 17 Dec 2009 17:04:44

Quote:

> I wish that the riders that are forgoing good headlights would at least
> put a white LED blinkie on the front too. If they don't need to see
> anything, at least they should be seen by drivers. Last week my wife
> turned right in front of a cyclist and almost hit him on the street
> perpendicular to ours. It was totally dark, he had no front light, and
> after he went past she noticed a ***tore quality rear flasher. He gave
> her the finger. She shook her head. His life was not even worth spending
> $20 on a light.

> Fortunately, riding without good lights seems to be the exception,
> rather than the rule, in my area.

I really appreciate the fact that a rear flasher has become the
default minimum lighting; relatively few cyclists in my town go
entirely without lighting, as they did twenty years ago.  (I think
this is at least in part because the cops now ticket cyclists for
insufficient lighting-- even if they do it capriciously and for
reasons unrelated to lighting.)

I am less enthused about the fact that these same folks often don't
keep up with their battery needs (like, don't get a Knog Frog if
you're not cool with replacing the tiny batteries often) or even use
reflectors anymore.

Chalo

 
 
 

"white" LED's vs. incandescent and halogen lights

Post by Tom Sherman °_ » Thu, 17 Dec 2009 18:12:52

Androcles WHO? ANONYMOUSLY SNIPES:
Quote:
> [...]
> I plonked that silly *** years ago, it's still stupid enough
> to respond to one of my posts.

Indeed, responding seriously to "Androcles" would be silly. ;)

--
Tom Sherman - 42.435731,-83.985007
I am a vehicular cyclist.

 
 
 

"white" LED's vs. incandescent and halogen lights

Post by Alistair Gun » Thu, 17 Dec 2009 18:47:11

In uk.rec.cycling Nate Nagel twisted the electrons to say:

Quote:

> > I don't think any of the riders I know with dynamos are using a wired
> > taillight, nor do I.  The battery powered LEDs are good enough.
> I do, but simply because I'm lazy (same reason I went with a dynamo in
> the first place.)  I like my bike to be just like a car, hop on and go.
>   If only someone would invent an inner tube that holds air as well as a
> car tire!

I will be too.  One of the points to switching to a dynamo powered system
was to get away from the hassles of batteries, seems pointless in that
case to retain a battery light.  Particularly the rear one, given that's
the one you can't check (/can't check nearly so easily) whilst riding to
see if the batteries have died ...
--
These opinions might not even be mine ...
Let alone connected with my employer ...
 
 
 

"white" LED's vs. incandescent and halogen lights

Post by Lou Holtma » Thu, 17 Dec 2009 21:33:30


Quote:
> Tue, 15 Dec 2009 19:37:44 -0600, Tim McNamara:

> >I don't think any of the riders I know with dynamos are using a wired
> >taillight, nor do I. ?The battery powered LEDs are good enough.

> From a european point of view: The fast majority of bikes with
> (hub)-dynamos let the generator power front *and* rear light. I see no
> advantage of a battery powered rear light. Even buying and changing the
> batteries once is more effort than wiring the rear light.

From a European point of view US cyclists are a special breed. Having
a generator powered front light and a battery powered rear light on a
utility bike is something I can't understand as an European.

Quote:
> Also there is a lack of good rear lights which can be permanently mounted.
> I would not want to take my lights of at any destination (and there might
> be 3-5 at one evening). Taking the light off always (and especially with
> the ice cold hands now) has the risk of letting it fall to the ground and
> destroy it. Carrying the battery in a bag with other stuff always has the
> risk of switching it on unintentionally. Remounting the lights has the
> need to readjust the beam angle.

Agreed.

Quote:
> I measured run times of different LED-backlight sold in germany. The time
> before the light output starts to drop and the "low batt" warning LED
> lights up was between 6 and 50 hours - all with new high-quality alakline
> cells. If you look around on the streets at night you see lots of bikes
> with battery lights which only emit very little light because the
> batteries are drained.

Exactly

Quote:
> Riding my bike is my major mode of transport. I just want to use it and
> don't want to have any kind of avoidable maintenance or preparation.

Right.

Lou

 
 
 

"white" LED's vs. incandescent and halogen lights

Post by Paul » Fri, 18 Dec 2009 00:08:29

Chalo wrote, On 12/15/2009 7:38 PM:
Quote:
> <snip>
> I used to get VistaLite 5-LED rear flashers because they used AAs.
> When I discovered that VistaLite was owned by the anti-cyclist company
> Bell Sports, I started buying Planet Bike blinky lights instead.  I
> don't prefer the AAA battery size, but in practice it does not seem to
> be a problem.

> Chalo

Chalo,
Mind if I ask why you consider Bell Sports to be an "anti-cyclist
company". Is there something going on with Bell Sports that I'm not
aware of?

--

Paul D Oosterhout
I work for SAIC (but I don't speak for SAIC)

 
 
 

"white" LED's vs. incandescent and halogen lights

Post by Clive Georg » Fri, 18 Dec 2009 00:13:10


Quote:
> Chalo wrote, On 12/15/2009 7:38 PM:
>> <snip>
>> I used to get VistaLite 5-LED rear flashers because they used AAs.
>> When I discovered that VistaLite was owned by the anti-cyclist company
>> Bell Sports, I started buying Planet Bike blinky lights instead.  I
>> don't prefer the AAA battery size, but in practice it does not seem to
>> be a problem.

>> Chalo

> Chalo,
> Mind if I ask why you consider Bell Sports to be an "anti-cyclist
> company". Is there something going on with Bell Sports that I'm not aware
> of?

It's pretty obvious to anybody who's read these NGs for more than a couple
of months.
 
 
 

"white" LED's vs. incandescent and halogen lights

Post by Paul » Fri, 18 Dec 2009 00:25:34

Clive George wrote, On 12/16/2009 10:13 AM:
Quote:


>> Chalo wrote, On 12/15/2009 7:38 PM:

>>> <snip>
>>> I used to get VistaLite 5-LED rear flashers because they used AAs.
>>> When I discovered that VistaLite was owned by the anti-cyclist company
>>> Bell Sports, I started buying Planet Bike blinky lights instead.  I
>>> don't prefer the AAA battery size, but in practice it does not seem to
>>> be a problem.

>>> Chalo

>> Chalo,
>> Mind if I ask why you consider Bell Sports to be an "anti-cyclist
>> company". Is there something going on with Bell Sports that I'm not aware
>> of?

> It's pretty obvious to anybody who's read these NGs for more than a couple
> of months.

I think I know what you are getting at and I will just drop the matter
here...

--

Paul D Oosterhout
I work for SAIC (but I don't speak for SAIC)