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

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

Post by Androcle » Fri, 11 Dec 2009 14:01:08



Quote:

>> The latest fireflies from Nature now produce more than a million times
>> the
>> amount
>>  of light that a compact LED produces for even less electrical power.

> White LEDs can have an efficiency of 22% currently compared to a
> maximum possible efficiency for white light of 37%, fireflies are only
> 96% efficient.

They'd better change their Duracells over to Energizer Bunny cells, then.
 
 
 

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

Post by Dirk Bruere at NeoPa » Fri, 11 Dec 2009 14:48:31

Quote:


>> The latest fireflies from Nature now produce more than a million times the
>> amount
>>  of light that a compact LED produces for even less electrical power.

> White LEDs can have an efficiency of 22% currently compared to a
> maximum possible efficiency for white light of 37%, fireflies are only
> 96% efficient.

Latest record is around 190 lm/W
http://en.wikipedia.org/wiki/Luminous_efficacy

--
Dirk

http://www.transcendence.me.uk/ - Transcendence UK
http://www.theconsensus.org/ - A UK political party
http://www.blogtalkradio.com/onetribe - Occult Talk Show

 
 
 

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

Post by Androcle » Fri, 11 Dec 2009 14:55:40



Quote:


>>> The latest fireflies from Nature now produce more than a million times
>>> the
>>> amount
>>>  of light that a compact LED produces for even less electrical power.

>> White LEDs can have an efficiency of 22% currently compared to a
>> maximum possible efficiency for white light of 37%, fireflies are only
>> 96% efficient.

> Latest record is around 190 lm/W
> http://en.wikipedia.org/wiki/Luminous_efficacy

> --
> Dirk

How many watts does a firefly use, then?

 
 
 

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

Post by Dirk Bruere at NeoPa » Fri, 11 Dec 2009 16:37:50

Quote:





>>>> The latest fireflies from Nature now produce more than a million times
>>>> the
>>>> amount
>>>>  of light that a compact LED produces for even less electrical power.
>>> White LEDs can have an efficiency of 22% currently compared to a
>>> maximum possible efficiency for white light of 37%, fireflies are only
>>> 96% efficient.
>> Latest record is around 190 lm/W
>> http://en.wikipedia.org/wiki/Luminous_efficacy

>> --
>> Dirk

> How many watts does a firefly use, then?

No idea, but it is far higher efficiency than any current LED

--
Dirk

http://www.transcendence.me.uk/ - Transcendence UK
http://www.theconsensus.org/ - A UK political party
http://www.blogtalkradio.com/onetribe - Occult Talk Show

 
 
 

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

Post by Androcle » Fri, 11 Dec 2009 22:15:20



Quote:





>>>>> The latest fireflies from Nature now produce more than a million times
>>>>> the
>>>>> amount
>>>>>  of light that a compact LED produces for even less electrical power.
>>>> White LEDs can have an efficiency of 22% currently compared to a
>>>> maximum possible efficiency for white light of 37%, fireflies are only
>>>> 96% efficient.
>>> Latest record is around 190 lm/W
>>> http://en.wikipedia.org/wiki/Luminous_efficacy

>>> --
>>> Dirk

>> How many watts does a firefly use, then?

> No idea, but it is far higher efficiency than any current LED

Yeah, I figured it was much higher than 96% too. Pity you have no
idea what "none" is.
 
 
 

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

Post by Peter Col » Sat, 12 Dec 2009 01:15:25

Quote:


>> The latest fireflies from Nature now produce more than a million times the
>> amount
>>  of light that a compact LED produces for even less electrical power.

> White LEDs can have an efficiency of 22% currently compared to a
> maximum possible efficiency for white light of 37%, fireflies are only
> 96% efficient.

> --
>    Ron

According to this:
http://www.nature.com/nphoton/journal/v2/n1/full/nphoton.2007.251.html

and this:
http://www.bioluminescentbeetles.com/introduction.html

New measurements put quantum efficiency of firefly bioluminescence at 41
+/- 7.4%.

"Initially predicted to be around 88% efficient the firefly
bioluminescent quantum yield has recently been accurately identified to
be 41.0 7.4% which is still higher than those found in other forms of
bioluminescence, i.e. aequorin (17%), cypridina (28%) and bacteria (30%)
[4]."

 
 
 

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

Post by me » Sun, 13 Dec 2009 01:24:56


Quote:

> > It's obvious that the mundane "white" LED bicycle lights do not light
> > up the asphalt roads very well. ?Incandescents, halogens, and sodium
> > lights do better.

> Oh. ?Last week I had the chance to compare a well respected halogen lamp
> (BuM Lumotec Oval) to a well respected LED lamp (BuM IQ Fly) on the same
> (unlit, asphalt) road at the same time, both running from dynoubs on
> side by side bikes, and the IQ Fly did a damn site better job of
> lighting it up.

> So obvious to some, perhaps, but not me.

> Pete.
> --

ok,

So it looks like I'll have to to some unbiased testing.  It will take
a while.  Lifestyle hardships get in the way.  Just a homeless bum,
you know.

There are issues involving

1.  Spectral distribution from the emitting sources of light
2.  Spectral reflectance from whatever the light hits
3.  Reflective intensity of the individual colors
4.  Spectral perception of the individual
5.  Calibration of the reflected colors from a camera device and the
display device
6.  Mathematical dealings with superposition issues

I have the 'digital color utility' on my aging mac and an older
digital camcorder that I use for stills.  I don't have a high quality
LED lamp which costs too much for me to buy so maybe I'll be able to
borrow one to test.  I have an ancient 35mm camera with a light meter
that I will have to calibrate and buy a battery for.  I'll have to buy
a few LED's and potentiometers from a parts store.  I'll try to mount
them on a dissected cateye opticube.  I'll use my cheap digital
voltmeter to get the relation between power and illumination.  I have
a diffraction grating that might reveal something.  I'll mount it on a
toilet paper roll with a slit on the other end, and attach it to the
camera.  I'll use my set of oil crayons for color reference that I
previously used to make a panhandling sign.

I figure I'll eventually shoot around 50 still pix.  I might add a set
of fluorescent light pix.  I suppose I'll web it up eventually.

errata -

1.  many asphalt streets I've seen have varying amounts of small
exposed stones (limestone?) embedded on the surface that will reflect
yellows better than blues.  Trees and foliage have a lot of yellow
reflectance.

2.  Older people may experience yellowing of the lens in their eyes,
causing less sensitivity to blues.  Recently I recommended a 2 front-
light setup for a 60-something biker - one small blue-light flasher,
and a larger halogen with adjustable focus mounted on a flashlight
holder.  If you use the halogen only occasionally, the batteries
should last a long time :)

 
 
 

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

Post by thirty-si » Sun, 13 Dec 2009 03:17:43


Quote:


> > > It's obvious that the mundane "white" LED bicycle lights do not light
> > > up the asphalt roads very well. ?Incandescents, halogens, and sodium
> > > lights do better.

> > Oh. ?Last week I had the chance to compare a well respected halogen lamp
> > (BuM Lumotec Oval) to a well respected LED lamp (BuM IQ Fly) on the same
> > (unlit, asphalt) road at the same time, both running from dynoubs on
> > side by side bikes, and the IQ Fly did a damn site better job of
> > lighting it up.

> > So obvious to some, perhaps, but not me.

> > Pete.
> > --

> ok,

> So it looks like I'll have to to some unbiased testing. ?It will take
> a while. ?Lifestyle hardships get in the way. ?Just a homeless bum,
> you know.

> There are issues involving

> 1. ?Spectral distribution from the emitting sources of light
> 2. ?Spectral reflectance from whatever the light hits
> 3. ?Reflective intensity of the individual colors
> 4. ?Spectral perception of the individual
> 5. ?Calibration of the reflected colors from a camera device and the
> display device
> 6. ?Mathematical dealings with superposition issues

> I have the 'digital color utility' on my aging mac and an older
> digital camcorder that I use for stills. ?I don't have a high quality
> LED lamp which costs too much for me to buy so maybe I'll be able to
> borrow one to test. ?I have an ancient 35mm camera with a light meter
> that I will have to calibrate and buy a battery for. ?I'll have to buy
> a few LED's and potentiometers from a parts store. ?I'll try to mount
> them on a dissected cateye opticube. ?I'll use my cheap digital
> voltmeter to get the relation between power and illumination. ?I have
> a diffraction grating that might reveal something. ?I'll mount it on a
> toilet paper roll with a slit on the other end, and attach it to the
> camera. ?I'll use my set of oil crayons for color reference that I
> previously used to make a panhandling sign.

> I figure I'll eventually shoot around 50 still pix. ?I might add a set
> of fluorescent light pix. ?I suppose I'll web it up eventually.

> errata -

> 1. ?many asphalt streets I've seen have varying amounts of small
> exposed stones (limestone?) embedded on the surface that will reflect
> yellows better than blues. ?Trees and foliage have a lot of yellow
> reflectance.

> 2. ?Older people may experience yellowing of the lens in their eyes,
> causing less sensitivity to blues. ?Recently I recommended a 2 front-
> light setup for a 60-something biker - one small blue-light flasher,
> and a larger halogen with adjustable focus mounted on a flashlight
> holder. ?If you use the halogen only occasionally, the batteries
> should last a long time :)

You'll also want a reference grey card (shirt card) and a tape
measure..
 
 
 

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

Post by Frank Krygowsk » Sun, 13 Dec 2009 04:43:49


Quote:



> > > > It's obvious that the mundane "white" LED bicycle lights do not light
> > > > up the asphalt roads very well. ?Incandescents, halogens, and sodium
> > > > lights do better.

> > > Oh. ?Last week I had the chance to compare a well respected halogen lamp
> > > (BuM Lumotec Oval) to a well respected LED lamp (BuM IQ Fly) on the same
> > > (unlit, asphalt) road at the same time, both running from dynoubs on
> > > side by side bikes, and the IQ Fly did a damn site better job of
> > > lighting it up.

> > > So obvious to some, perhaps, but not me.

> > > Pete.
> > > --

> > ok,

> > So it looks like I'll have to to some unbiased testing. ?It will take
> > a while. ?Lifestyle hardships get in the way. ?Just a homeless bum,
> > you know.

> > There are issues involving

> > 1. ?Spectral distribution from the emitting sources of light
> > 2. ?Spectral reflectance from whatever the light hits
> > 3. ?Reflective intensity of the individual colors
> > 4. ?Spectral perception of the individual
> > 5. ?Calibration of the reflected colors from a camera device and the
> > display device
> > 6. ?Mathematical dealings with superposition issues

> > I have the 'digital color utility' on my aging mac and an older
> > digital camcorder that I use for stills. ?I don't have a high quality
> > LED lamp which costs too much for me to buy so maybe I'll be able to
> > borrow one to test. ?I have an ancient 35mm camera with a light meter
> > that I will have to calibrate and buy a battery for. ?I'll have to buy
> > a few LED's and potentiometers from a parts store. ?I'll try to mount
> > them on a dissected cateye opticube. ?I'll use my cheap digital
> > voltmeter to get the relation between power and illumination. ?I have
> > a diffraction grating that might reveal something. ?I'll mount it on a
> > toilet paper roll with a slit on the other end, and attach it to the
> > camera. ?I'll use my set of oil crayons for color reference that I
> > previously used to make a panhandling sign.

> > I figure I'll eventually shoot around 50 still pix. ?I might add a set
> > of fluorescent light pix. ?I suppose I'll web it up eventually.

> > errata -

> > 1. ?many asphalt streets I've seen have varying amounts of small
> > exposed stones (limestone?) embedded on the surface that will reflect
> > yellows better than blues. ?Trees and foliage have a lot of yellow
> > reflectance.

> > 2. ?Older people may experience yellowing of the lens in their eyes,
> > causing less sensitivity to blues. ?Recently I recommended a 2 front-
> > light setup for a 60-something biker - one small blue-light flasher,
> > and a larger halogen with adjustable focus mounted on a flashlight
> > holder. ?If you use the halogen only occasionally, the batteries
> > should last a long time :)

> You'll also want a reference grey card (shirt card) and a tape
> measure..

Alternately, you could ride your bike and look.  That's worked for
many of us.

It's a simple plan, but we like it.

- Frank Krygowski

 
 
 

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

Post by N8N » Sun, 13 Dec 2009 04:58:55


Quote:

> > It's obvious that the mundane "white" LED bicycle lights do not light
> > up the asphalt roads very well. ?Incandescents, halogens, and sodium
> > lights do better.

> Oh. ?Last week I had the chance to compare a well respected halogen lamp
> (BuM Lumotec Oval) to a well respected LED lamp (BuM IQ Fly) on the same
> (unlit, asphalt) road at the same time, both running from dynoubs on
> side by side bikes, and the IQ Fly did a damn site better job of
> lighting it up.

> So obvious to some, perhaps, but not me.

Odd, I recently replaced a standard Lumotec with an IQ Cyo and the
difference to me was astonishing - in favor of the IQ Cyo.

nate

 
 
 

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

Post by Chal » Sun, 13 Dec 2009 10:02:48

Quote:

> Buy a light. If it's not bright enough for you, buy something else.
> With the time you save from NOT doing the tests you outlined, study
> investments. You'll make much more money than you'll ever spend on
> lights.

Oy!  If only it were so!
 
 
 

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

Post by thirty-si » Sun, 13 Dec 2009 10:31:40


Quote:




> > > > > It's obvious that the mundane "white" LED bicycle lights do not light
> > > > > up the asphalt roads very well. ?Incandescents, halogens, and sodium
> > > > > lights do better.

> > > > Oh. ?Last week I had the chance to compare a well respected halogen lamp
> > > > (BuM Lumotec Oval) to a well respected LED lamp (BuM IQ Fly) on the same
> > > > (unlit, asphalt) road at the same time, both running from dynoubs on
> > > > side by side bikes, and the IQ Fly did a damn site better job of
> > > > lighting it up.

> > > > So obvious to some, perhaps, but not me.

> > > > Pete.
> > > > --

> > > ok,

> > > So it looks like I'll have to to some unbiased testing. ?It will take
> > > a while. ?Lifestyle hardships get in the way. ?Just a homeless bum,
> > > you know.

> > > There are issues involving

> > > 1. ?Spectral distribution from the emitting sources of light
> > > 2. ?Spectral reflectance from whatever the light hits
> > > 3. ?Reflective intensity of the individual colors
> > > 4. ?Spectral perception of the individual
> > > 5. ?Calibration of the reflected colors from a camera device and the
> > > display device
> > > 6. ?Mathematical dealings with superposition issues

> > > I have the 'digital color utility' on my aging mac and an older
> > > digital camcorder that I use for stills. ?I don't have a high quality
> > > LED lamp which costs too much for me to buy so maybe I'll be able to
> > > borrow one to test. ?I have an ancient 35mm camera with a light meter
> > > that I will have to calibrate and buy a battery for. ?I'll have to buy
> > > a few LED's and potentiometers from a parts store. ?I'll try to mount
> > > them on a dissected cateye opticube. ?I'll use my cheap digital
> > > voltmeter to get the relation between power and illumination. ?I have
> > > a diffraction grating that might reveal something. ?I'll mount it on a
> > > toilet paper roll with a slit on the other end, and attach it to the
> > > camera. ?I'll use my set of oil crayons for color reference that I
> > > previously used to make a panhandling sign.

> > > I figure I'll eventually shoot around 50 still pix. ?I might add a set
> > > of fluorescent light pix. ?I suppose I'll web it up eventually.

> > > errata -

> > > 1. ?many asphalt streets I've seen have varying amounts of small
> > > exposed stones (limestone?) embedded on the surface that will reflect
> > > yellows better than blues. ?Trees and foliage have a lot of yellow
> > > reflectance.

> > > 2. ?Older people may experience yellowing of the lens in their eyes,
> > > causing less sensitivity to blues. ?Recently I recommended a 2 front-
> > > light setup for a 60-something biker - one small blue-light flasher,
> > > and a larger halogen with adjustable focus mounted on a flashlight
> > > holder. ?If you use the halogen only occasionally, the batteries
> > > should last a long time :)

> > You'll also want a reference grey card (shirt card) and a tape
> > measure..

> Alternately, you could ride your bike and look. ?That's worked for
> many of us.

> It's a simple plan, but we like it.

I've already sorted that.  In conditions were road lighting could be
better and I need projection on the road, by current blue tint LED
mixes well with the available yellow sodium.  Under better road
lighting then the blueness is more noticeable to other road users.
With no road lighting, the level of illumination is relatively poor
and is best supplemented with an incandescent of normal 2-3W levels.
it would be nice to see specifically what defects are and are not
shown up by the LED without risking riding unlit roads.at speed.
 
 
 

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

Post by Ron Peterso » Sun, 13 Dec 2009 13:57:16


Quote:
> I've already sorted that. ?In conditions were road lighting could be
> better and I need projection on the road, by current blue tint LED
> mixes well with the available yellow sodium. ?Under better road
> lighting then the blueness is more noticeable to other road users.
> With no road lighting, the level of illumination is relatively poor
> and is best supplemented with an incandescent of normal 2-3W levels.
> it would be nice to see specifically what defects are and are not
> shown up by the LED without risking riding unlit roads.at speed.

The rods of the eye are most sensitive to blue light.

--
    Ron

 
 
 

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

Post by Tom Kea » Sun, 13 Dec 2009 15:55:47



Quote:



>> > Are "white" LEDs legally white. As in, a white lamp must be fitted to
>> > the front of the vehicle and a red lamp must (usually) be fitted to
>> > the rear and operational during times of darkness.
>> > ==========================================
>> > Yes, they are. If you compare older incandescent car headlights
>> > with later halogen lights one will appear to have a yellow tinge
>> > whilst the other appears bluish. Both are legally white.
>> > http://www.catdiaries.co.uk/images/photography_personal/img_1.jpg
>> > From a legal standpoint you can use a hurricane lamp if you wish,
>> > or even a candle with a glass wind shield. There is no legal requirement
>> > to use an electric light, the law was made before electric lighting
>> > became commonly available.
>> > http://img1.photographersdirect.com/img/15262/wm/pd1068794.jpg
>> > Legally the lights are required so that you can be seen, not for you to
>> > see by; in Britain a high brightness red rear fog lamp is now a legal
>> > requirement.

>> That was the issue all along - that it's based on power not brightness.
>> It's how you can have incredibly bright car headlights based on halogen
>> and other metals and really shite yellowish bulbs that are still bits of
>> coiled wire - both are perfectly legal as the power consumption is the
>> same.
>> LED's gave us the chance to 'shine', the battery life is a bonus.

> I don't think there is any point in attempting to compete with car
> headlights.

There seems to be a mindset that that is indeed what
bike riders need to do, either in terms of o/p wattage
or brightness.  In city traffic, blinking lights + speed
difference + positioning on the street does the trick
nicely -- as long as the batteries don't fade.

On lightly-driven country highways at night, just about
any kind of light sticks out like a sore thumb.

Quote:
> If we can obtain similar brightness and size to a 24W
> incandescent (not legal) reversing lamp then we have all the
> visibility requirements we need.  Experience shows this is way in
> excess of what we need to illuminate the road effevtively.  I have a
> flood type car headlamp reflector of around 3" and would like to see
> this with an LED driver fitted if possible.

It's very nice to be able to cast a luminous spot on the
city streets at night when approaching intersections in order
to announce one's approach to any possible cross traffic;
epecially at blind intersections, which should be dealt
with gingerly anyways.  'Cuz chances are, any cross-traffic
drivers there won't be alert to the approach of car
headlights, let alone bike lights.  So we have to be
alert for them.

I guess just having lights on is no excuse for having
one's guard down.

cheers,
        Tom

--
Nothing is safe from me.
I'm really at:
tkeats curlicue vcn dot bc dot ca

 
 
 

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

Post by Just zis Guy, you know » Sun, 13 Dec 2009 18:28:44

On Fri, 11 Dec 2009 20:57:16 -0800 (PST), Ron Peterson

Quote:

>> I've already sorted that. In conditions were road lighting could be
>> better and I need projection on the road, by current blue tint LED
>> mixes well with the available yellow sodium. Under better road
>> lighting then the blueness is more noticeable to other road users.
>> With no road lighting, the level of illumination is relatively poor
>> and is best supplemented with an incandescent of normal 2-3W levels.
>> it would be nice to see specifically what defects are and are not
>> shown up by the LED without risking riding unlit roads.at speed.

>The rods of the eye are most sensitive to blue light.

And the people who actually know about lighting are audax riders, who
ride in all kinds of lighting conditions right down to pitch black and
in all kinds of weathers.

I'd also suggest that anyone who judges LED lights without having
tried the most recent offerings from B&M and others, is probably not
going to be in possession of all the facts.  They have improved
dramatically in recent times.  A D-Lumotec might justly be
characterised as thirty-six described, but the IQ Cyo definitely
can't.

LEDs have definitely moved from the being-seen into the seeing-by
category.

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