Something I'm considering seriously given the potential for energy
reduction.

A feedback comment from a customer on one of the supplier sites
mentioned that he'd been able to use these 12v units connected to a car
battery in a stable without any electricity supply.

This got me thinking. Considering the frequency of power cuts where I
live, might it be a good idea to introduce a backup battery into the
circuit, with overcharge protection naturally?

What I don't know is whether this would be in violation of any safety
standards, or even if there are any standards for this new technology.

In article . com,
Jeff Mowatt wrote:
Something I'm considering seriously given the potential for energy
reduction.

There isn't any, really. Not much to pick and choose between those and
fluorescents.

A feedback comment from a customer on one of the supplier sites
mentioned that he'd been able to use these 12v units connected to a car
battery in a stable without any electricity supply.

Same as fluorescents. But they tend to give a more usable light.

This got me thinking. Considering the frequency of power cuts where I
live, might it be a good idea to introduce a backup battery into the
circuit, with overcharge protection naturally?

Can do. But you could equally as easily do this for mains stuff, or other
LV technology.

What I don't know is whether this would be in violation of any safety
standards, or even if there are any standards for this new technology.

At the moment it's just yet another new fad. Some uses for specialist
apps. But no 'killer' yet.

--
*I'm already visualizing the duct tape over your mouth

Dave Plowman London SW
To e-mail, change noise into sound.

On 21 Nov 2006 05:45:12 -0800, "Jeff Mowatt"
wrote:

Something I'm considering seriously given the potential for energy
reduction.

They use more energy than a fluorescent lamp for equivalent light
output.

What I don't know is whether this would be in violation of any safety
standards, or even if there are any standards for this new technology.

It's just a 12V lamp made up from a LED cluster, nothing unusual
about it. Used off a 12V battery a good LED lamp will probably have
better efficiency than a caravan type fluorescent with a cheap built
in inverter but there won't be much in it.

A simpler solution might be to use something like
http://www.woolworths.co.uk/ww_p2/pr...l?pid=50524567

or a maintained emergency light such as

http://www.tlc-direct.co.uk/Main_Index/Lighting_Menu_Index/Lighting_Emergency_Index/Maintained_3_Hours_1/index.html

with a modification to the mains fail side to make it switchable (as
it is the battery powered tube comes on automatically if power
fails).
--
Peter Parry.
http://www.wpp.ltd.uk/

The message
from Peter Parry contains these words:

Something I'm considering seriously given the potential for energy
reduction.

They use more energy than a fluorescent lamp for equivalent light
output.

The current record for LED efficiency is 132 Lumens/watt - something
fluorescent lamps struggle to approach.

Generally available white LEDs achieve 65 Lumens/watt. As far as I can
find, CFLs range about the same, from 45 to 70 lumens/watt.

So - while a year or three ago LEDs were less efficient than CFLs, they
are now comparable, with the likelyhood of them being much more
efficient than CLFs in the near future.

--
Skipweasel
Pay no attention to that man behind the curtain.

Guy King wrote:
The message
from Peter Parry contains these words:

Something I'm considering seriously given the potential for energy
reduction.

They use more energy than a fluorescent lamp for equivalent light
output.

The current record for LED efficiency is 132 Lumens/watt - something
fluorescent lamps struggle to approach.

Not for white.
You may as well claim 180lm/W as a figure to compare with (yellow
low-pressure sodium, as used to be seen lots in streetlights).

Generally available white LEDs achieve 65 Lumens/watt. As far as I can
find, CFLs range about the same, from 45 to 70 lumens/watt.


I assume you are talking about LEDs like the cree XLamp 7090 XR-E LED.

This does indeed claim boldly on the website that it gets 70lm
'typical'.
However.
This is with cooling, in 99% of environments, as it only hits that with
the point the LEDs are soldered to at 17C, neglecting any further
temperature rise in the heatsink.

At a Tj of 60C or so, which is a heatsink temperature of 50C, which may
be just about packagable into a normal CFL bulb shaped device (without a
fan), you're down to 90% of this figure.

Add a 90% efficient power supply, and we're at 80%.
For 70lm/w, this is 56lm/W.
However, they do not guarantee that you will get 70lm, the minimum
brightness bin is 62lm/W, which drops it a fair way.

So - while a year or three ago LEDs were less efficient than CFLs, they
are now comparable, with the likelyhood of them being much more
efficient than CLFs in the near future.

The other problem...

Now, look at the spectral distribution of this LED.
It's _horrible_ for lighting - most of the light comes out as blue, with
some yellow to make it whitish.
Putting in a better phosphor mix drops it quite a lot.

Getting there, but quite a way to go yet.

In article ,
Guy King wrote:
The message
from Peter Parry contains these words:

Something I'm considering seriously given the potential for energy
reduction.

They use more energy than a fluorescent lamp for equivalent light
output.

The current record for LED efficiency is 132 Lumens/watt - something
fluorescent lamps struggle to approach.

Be interesting to know the spectrum output of that LED versus the florry.

Generally available white LEDs achieve 65 Lumens/watt. As far as I can
find, CFLs range about the same, from 45 to 70 lumens/watt.

Again, wonder how this output is measured? A fluorescent gives
substantially 360 degree light output. LEDs don't.

So - while a year or three ago LEDs were less efficient than CFLs, they
are now comparable, with the likelyhood of them being much more
efficient than CLFs in the near future.

--
*No radio - Already stolen.

Dave Plowman London SW
To e-mail, change noise into sound.

The message
from Ian Stirling contains these words:

The current record for LED efficiency is 132 Lumens/watt - something
fluorescent lamps struggle to approach.

Not for white.

Yes, for white.
http://www.dvorak.org/blog/?p=5822

--
Skipweasel
Pay no attention to that man behind the curtain.

Dave Plowman (News) wrote:
In article ,
Guy King wrote:
The message
from Peter Parry contains these words:

Something I'm considering seriously given the potential for energy
reduction.

They use more energy than a fluorescent lamp for equivalent light
output.

The current record for LED efficiency is 132 Lumens/watt - something
fluorescent lamps struggle to approach.

Be interesting to know the spectrum output of that LED versus the florry.

Generally available white LEDs achieve 65 Lumens/watt. As far as I can
find, CFLs range about the same, from 45 to 70 lumens/watt.

Again, wonder how this output is measured? A fluorescent gives
substantially 360 degree light output. LEDs don't.

Thats down to lenses and diffusers.

actually there are some electroluminescent materials around that look
set to challenge both technologies in a few years time..likely to turn
up first behind the LCD display on your phone etc. IIRC the conversion
efficiency as better than LED, not quite so good as top notch
fluorescent, but close to it.





So - while a year or three ago LEDs were less efficient than CFLs, they
are now comparable, with the likelyhood of them being much more
efficient than CLFs in the near future.

The message
from "Dave Plowman (News)" contains these words:

Again, wonder how this output is measured? A fluorescent gives
substantially 360 degree light output. LEDs don't.

Doesn't matter - it's how much light comes out per watt in. Fluoro's
360° can be a right PITA, as much of it hits the fitting instead of
going where it's wanted. With LEDs you can shove it where the light
doesn't shine.

--
Skipweasel
Pay no attention to that man behind the curtain.

Guy King wrote:


Doesn't matter - it's how much light comes out per watt in. Fluoro's
360° can be a right PITA, as much of it hits the fitting instead of
going where it's wanted. With LEDs you can shove it where the light
doesn't shine.

Indeed, and if the pioneers of the CFL technology are now making big
investment in LED production, that's indication enough for me that
they're viable.

Meanwhile I may buy some tealights!

http://www.nam.lighting.philips.com/...lay.php?mode=2

"Dave Plowman (News)" wrote in message
...
In article ,
Guy King wrote:
The message
from Peter Parry contains these words:

Something I'm considering seriously given the potential for energy
reduction.

They use more energy than a fluorescent lamp for equivalent light
output.

The current record for LED efficiency is 132 Lumens/watt - something
fluorescent lamps struggle to approach.

Be interesting to know the spectrum output of that LED versus the florry.

Generally available white LEDs achieve 65 Lumens/watt. As far as I can
find, CFLs range about the same, from 45 to 70 lumens/watt.

Again, wonder how this output is measured? A fluorescent gives
substantially 360 degree light output. LEDs don't.

So - while a year or three ago LEDs were less efficient than CFLs, they
are now comparable, with the likelyhood of them being much more
efficient than CLFs in the near future.

--
*No radio - Already stolen.

Dave Plowman London SW
To e-mail, change noise into sound.

I thought the whole point of LED light units/clusters was that LED's last a
lot longer than conventional bulbs/CFL???
Or am I thinking of something totally different?! :-)
______________________________________
The Grim Reaper

In article ,
The Grim Reaper wrote:
I thought the whole point of LED light units/clusters was that LED's
last a lot longer than conventional bulbs/CFL??? Or am I thinking of
something totally different?! :-)

LEDs when used as panel signalling lamps have a near infinite life. Not
quite the same when you up the current to get some useful light out of
them, though.

--
*Stable Relationships Are For Horses.

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:
In article ,
The Grim Reaper wrote:
I thought the whole point of LED light units/clusters was that LED's
last a lot longer than conventional bulbs/CFL??? Or am I thinking of
something totally different?! :-)

LEDs when used as panel signalling lamps have a near infinite life. Not
quite the same when you up the current to get some useful light out of
them, though.

Agreed. Lifetime of semiconductors is very much heat related..apart from
heat/cool/expansion mechanical seal fracture stuff, the doping gradually
migrates and diffuses..transistors do 'age'..and very rapidly as the
junction temperatures increase to near the critical points - around
175-200C for silicon, less for germanium,, dunno with gallium.

Nevertheless, not used continuously I would expect 20 years or more life
out of a LED.

In article ,
The Natural Philosopher wrote:
Nevertheless, not used continuously I would expect 20 years or more life
out of a LED.

There's a surprising number of cars around with faulty LED third brake
lights. Of course it may be the resistors.

--
*Do paediatricians play miniature golf on Wednesdays?

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Dave Plowman (News) wrote:

There's a surprising number of cars around with faulty LED third
brake lights. Of course it may be the resistors.

My handbook says that repairing the third brake
light LED cluster is a main-agent job only, and
I suspect it would be a complete replacement.
Perhaps that's why they don't get seen to.

--
Tony Williams.

The message
from Tony Williams contains these words:

My handbook says that repairing the third brake
light LED cluster is a main-agent job only, and
I suspect it would be a complete replacement.
Perhaps that's why they don't get seen to.

I bet it's fairly simple inside.

--
Skipweasel
Pay no attention to that man behind the curtain.

Dave Plowman (News) wrote:
In article ,
Guy King wrote:
The message
from Peter Parry contains these words:

Something I'm considering seriously given the potential for energy
reduction.

They use more energy than a fluorescent lamp for equivalent light
output.

The current record for LED efficiency is 132 Lumens/watt - something
fluorescent lamps struggle to approach.

Be interesting to know the spectrum output of that LED versus the florry.

Cheap fluro can have terrible colour rendering, old halo p0hosphates
could go as low as 55 CRI , good fluoro will be 90+ CRI, halogen light
and daylight are CRI 100.


Generally available white LEDs achieve 65 Lumens/watt. As far as I can
find, CFLs range about the same, from 45 to 70 lumens/watt.

Again, wonder how this output is measured? A fluorescent gives
substantially 360 degree light output. LEDs don't.

Lumens is a measure of total light output regardless of direction, its
measured in an integrating sphere. Lux is delivered light in a given
direction and Candela is directed light where the number increases with
narrower angle, hence some of the ridiculous Cd figures you see for
some LEDs, narrow beam angle high Cd numbers.


So - while a year or three ago LEDs were less efficient than CFLs, they
are now comparable, with the likelyhood of them being much more
efficient than CLFs in the near future.

In the manufactures very well chilled labs perhaps. Remember also lumen
depreciation like fluros lamp dosen`t just die its output drops over
time, Lumileds puts Luxeon white dropping to approximately 70% after
50K hours, in ideal conditions.


Adam
--
*No radio - Already stolen.

Dave Plowman London SW
To e-mail, change noise into sound.

Adam Aglionby wrote:

Remember also lumen depreciation like fluros lamp dosen`t just die
its output drops over time, [...]

Cheap indicator LEDs dim with age far more than many people realise. A
demonstration can often be seen on a computer keyboard. If you keep
NumLock on all the time, but only use CapsLock now and again (and
ScrollLock never) put them all on and compare the brightness of the LEDs.

--
Andy

The message
from Andy Wade contains these words:

Cheap indicator LEDs dim with age far more than many people realise. A
demonstration can often be seen on a computer keyboard. If you keep
NumLock on all the time, but only use CapsLock now and again (and
ScrollLock never) put them all on and compare the brightness of the LEDs.

I can't see either of mine under the dirt.

--
Skipweasel
Pay no attention to that man behind the curtain.

Jeff Mowatt wrote:
Something I'm considering seriously given the potential for energy
reduction.

A feedback comment from a customer on one of the supplier sites
mentioned that he'd been able to use these 12v units connected to a car
battery in a stable without any electricity supply.

This got me thinking. Considering the frequency of power cuts where I
live, might it be a good idea to introduce a backup battery into the
circuit, with overcharge protection naturally?

What I don't know is whether this would be in violation of any safety
standards, or even if there are any standards for this new technology.

About 30 years ago, my brother was involved in the installation
of small wind turbines of about 2kWatt size. This was in Switzerland at
an area called Little Siberia. It is a farming plateau. The wind mills
just provided 12 Volt lighting for farm buildings. Their saving was not
electrically based but their INSURANCE premiums dropped because they
were using oil based lighting previously. The white mans burden,
INSURANCE.

Chris.

On 2006-11-23 13:17:07 +0000, " said:


About 30 years ago, my brother was involved in the installation
of small wind turbines of about 2kWatt size. This was in Switzerland at
an area called Little Siberia. It is a farming plateau. The wind mills
just provided 12 Volt lighting for farm buildings. Their saving was not
electrically based but their INSURANCE premiums dropped because they
were using oil based lighting previously. The white mans burden,
INSURANCE.

Chris.

Especially if you're Swiss.

Somebody once said to me that the Swiss tend to be very risk averse
with four policies to adopt when making a decision on something

- Sicherheit
- Sécurité
- Sicurezza
- Segirtad

but then just to be completely safe....

- Versicherung

In message , Andy Hall writes
On 2006-11-23 13:17:07 +0000, " said:

About 30 years ago, my brother was involved in the
installation
of small wind turbines of about 2kWatt size. This was in Switzerland at
an area called Little Siberia. It is a farming plateau. The wind mills
just provided 12 Volt lighting for farm buildings. Their saving was not
electrically based but their INSURANCE premiums dropped because they
were using oil based lighting previously. The white mans burden,
INSURANCE.
Chris.

Especially if you're Swiss.

Somebody once said to me that the Swiss tend to be very risk averse
with four policies to adopt when making a decision on something

- Sicherheit
- Sécurité
- Sicurezza


- Segirtad

That's what Romanish looks like then ?

Eastern european looking


but then just to be completely safe....

- Versicherung




--
geoff

On 2006-11-25 00:26:48 +0000, raden said:

In message , Andy Hall writes


- Segirtad

That's what Romanish looks like then ?

Eastern european looking


It does in a way. I thought the same about Romanian during a recent
trip there - interesting place. It was clear that that is a romance
language as well - anyone with a knowledge of French, Italian, etc.
could figure out a reasonable proportion of words in a written
document, although there is a definite slavic feel to it as well.

However I'm told that Romansh is one of the western group of Romance
languages so somewhat different. I suppose to a German speaker,
Swiss-German sounds pretty strange - the pronunciation of the the same
words, where they asre used, is very different.

In message , Andy Hall writes
On 2006-11-25 00:26:48 +0000, raden said:

In message , Andy Hall writes

- Segirtad
That's what Romanish looks like then ?
Eastern european looking


It does in a way. I thought the same about Romanian during a recent
trip there - interesting place. It was clear that that is a romance
language as well - anyone with a knowledge of French, Italian, etc.
could figure out a reasonable proportion of words in a written
document, although there is a definite slavic feel to it as well.

However I'm told that Romansh is one of the western group of Romance
languages so somewhat different. I suppose to a German speaker,
Swiss-German sounds pretty strange -

You misspelt "unintelligible" there

--
geoff