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

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

Post by thirty-si » Thu, 17 Dec 2009 06:04:31



Quote:



> >>> ?Especially because for a rear LED light you want one
> >>> with multiple LEDs, at least two of which are side pointing. Buy a
> >>> CatEye TD-LD1100 for $28 and be done with it.
> >>> "http://www.lickbike.com/productpage.aspx?PART_NUM_SUB=%273340-00%27"
> >> Run it on 2900 mAh NiMHs and you are sorted.

> > Actually, a rear blinky is a great application for a low internal
> > discharge NiMH like the Rayovac Hybrid or Sanyo Eneloop. ?Even though
> > they hold 2000-2200mAh, which is less than a conventional NiMH, they
> > usually need less less frequent charging. ?They won't be ruined if you
> > forget about them for a year. ?A regular NiMH can easily lose more
> > juice to self-discharge than to running the blinky for a short time
> > each day.

> This is true. But in reality, a rear LED light lasts so long on a set of
> batteries that even alkalines are okay.

> One thing to be sure of is to get a rear flasher that uses AA cells, not
> AAA cells. The Blackburn Mars also has side pointing LEDs like the
> CatEye TD-LD1100, but it uses AAA batteries.

So use lithiums.
 
 
 

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

Post by Frank Krygowsk » Thu, 17 Dec 2009 06:26:24


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.

- Frank Krygowski

 
 
 

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

Post by AMuz » Thu, 17 Dec 2009 06:32:24

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.

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

 
 
 

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

Post by SMS » Thu, 17 Dec 2009 07:12:06

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.

 
 
 

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

Post by SMS » Thu, 17 Dec 2009 07:47:55

Quote:

>> One thing to be sure of is to get a rear flasher that uses AA cells, not
>> AAA cells. The Blackburn Mars also has side pointing LEDs like the
>> CatEye TD-LD1100, but it uses AAA batteries.

> So use lithiums.

Lithium non-rechargeables are fine. Also you can use a 14500 AA sized
lithium-ion rechargeable in conjunction with a dummy AA cell in most
stuff that takes two AA cells. It's 3.6V but it works.

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. If you've ever
seen the modules to upgrade a Maglite to an LED, you'll notice the heat
sinking they do to prevent heat from destroying the LED, i.e.
"http://ecx.images-amazon.com/images/I/51BsS5W756L._SL500_AA280_.jpg" or
  "http://ecx.images-amazon.com/images/I/41O-qT14XNL._AA280_.jpg".

For a dynamo bulb, the replacement module also needs to house a bridge
rectifier and a voltage regulator, both of which generate additional heat.

 
 
 

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

Post by Just zis Guy, you know » Thu, 17 Dec 2009 07:49:20

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'.

Unless the lighting is factory fitted (as with many European utility
bikes and also the Brompton folder)

Guy
--
http://www.chapmancentral.co.uk/urc
GPG public key at http://www.chapmancentral.co.uk/pgp-public-key.txt

 
 
 

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

Post by Just zis Guy, you know » Thu, 17 Dec 2009 08:21:06



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.

Guy
--
http://www.chapmancentral.co.uk/urc
GPG public key at http://www.chapmancentral.co.uk/pgp-public-key.txt

 
 
 

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

Post by Nate Nage » Thu, 17 Dec 2009 08:57:29

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?

nate

--
replace "roosters" with "cox" to reply.
http://SportToday.org/

 
 
 

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

Post by Chal » Thu, 17 Dec 2009 09:38:43

Quote:


> > Actually, a rear blinky is a great application for a low internal
> > discharge NiMH like the Rayovac Hybrid or Sanyo Eneloop.  Even though
> > they hold 2000-2200mAh, which is less than a conventional NiMH, they
> > usually need less less frequent charging.  They won't be ruined if you
> > forget about them for a year.  A regular NiMH can easily lose more
> > juice to self-discharge than to running the blinky for a short time
> > each day.

> This is true. But in reality, a rear LED light lasts so long on a set of
> batteries that even alkalines are okay.

Sure.  In fact, it would be very difficult to amortize the added
expense of NiMH cells during the median lifespan of a rear blinky.
But if you're going to use rechargeables, low internal discharge ones
are the way to go.

Quote:
> One thing to be sure of is to get a rear flasher that uses AA cells, not
> AAA cells. The Blackburn Mars also has side pointing LEDs like the
> CatEye TD-LD1100, but it uses AAA batteries.

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

 
 
 

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

Post by Chal » Thu, 17 Dec 2009 10:00:01


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.  LEDs are damaged by relatively
low temperatures-- for example, residual heat from soldering their
leads can harm them if joints are not soldered quickly enough.

Chalo

 
 
 

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

Post by Tim McNamar » Thu, 17 Dec 2009 10:37:44


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.
 
 
 

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

Post by Nate Nage » Thu, 17 Dec 2009 10:39:43

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.
  If only someone would invent an inner tube that holds air as well as a
car tire!

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

 
 
 

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

Post by Clive Georg » Thu, 17 Dec 2009 10:58:02


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.

Me too. It helps that my home-brew LED rear lamps have been very reliable
over the past ten or so years. Also due to the way they're wired (in
series), I can see if my back lamp is on by looking at the front. (well, bar
a short of the wires going to the rear).

My wife's folder has a battery driven rear lamp. It's on its third now in
under two years :-(

 
 
 

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

Post by Patrick Lam » Thu, 17 Dec 2009 11:37:41



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?

If you're just going to try it once and declare it unsafe, can you
order a Cyo R Plus to go with it, and give me first dibs when you
re-sell the package?

Pat

Email address works as is.

 
 
 

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

Post by SMS » Thu, 17 Dec 2009 13:27:21

<snip>

Quote:
> 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.  LEDs are damaged by relatively
> low temperatures-- for example, residual heat from soldering their
> leads can harm them if joints are not soldered quickly enough.

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.

There are people that believe that LEDs don't generate heat like the
"white hot filament" of an incandescent bulb, and they're partially
write--the LEDs generate heat in an entirely different way.

There's other problems with LED lights related to thermal issues as
well, as many cities that switched to LED traffic lights have found. The
heat that LEDs generate is, as you stated, retained in the device, while
heat from incandescent bulbs radiates out. This heat has a critical
function in traffic lights.