New 10-watt(?) LED Light

Quoted message said:

The new Summer Performance catalog is featuring their new
"ViewPoint GEN3" single Luxeon LED headlight. They claim
"10 watts plus" coming out of 4 AA NiMH batteries that run
5 hours.

Here's why their claim is hard to believe:

(10 watts) x (5 hours) / (4 cells) = 12.5 watt-hours per
cell

Four watt-hours per AA cell is about the best you can
expect. I'm thinking they're using a Luxeon 5-watt LED [URL
below] and running the batteries dead flat, long after the
light dims below full output (in about three hours), to get
five hours out of them.

Quoted message said:

I think what they really mean is the LED light is
equivalent in brightness to a typical 10-watt
halogen light.

From my experiments with bike lights, I'd say there seems
to be about a two-to-one ratio of apparent brightness
between LED and halogen lights, so the 5-watt LED may well
look as bright as a 10-watt halogen.

luxeonstar.comsub category.phpOpen ↗

I thought this was reaching a bit in the 10-watt claim as
well. For comparison, here is a discussion on the
performance of a caving lamp using a similar Luxeon LED.
They claim it's 5 watts. It may be the same emitter.

caves.orgNova%20discharge.pdfOpen ↗

It's kind of vague, but in general it demonstrates that
Speleotechnics claims about half the life for half the
wattage of the Performance light. Also there are some
instruction for its use.

caves.orgNOVA%20instructions.pdfOpen ↗

Then again, it would be really nice if companies would start
describing their lights in comparable terms, like using
"Lux" or "lumens" to describe the actaul amount of light
output by the light. Not many people understand these terms
(I have to look it up all the time because I forget), but
many companies are now using fake "Wattage" values in an
attempt to compare LEDs with filament bulbs.

Incidentally, the digital versions are the best thing in
the world for caving. They do such a good job of
flattening out the voltage curve that you never notice a
drain on the battery, and you get maximum life out of the
battery as well.

-Collin

LioNiNoiL_a t_Ne t s c a pE_D 0 T_Ne T said:

Quoted message said:

The new Summer Performance catalog is featuring their new
"ViewPoint GEN3" single Luxeon LED headlight. They claim
"10 watts plus" coming out of 4 AA NiMH batteries that
run 5 hours.

Here's why their claim is hard to believe:

(10 watts) x (5 hours) / (4 cells) = 12.5 watt-hours
per cell

Four watt-hours per AA cell is about the best you can
expect. I'm thinking they're using a Luxeon 5-watt LED
[URL below] and running the batteries dead flat, long
after the light dims below full output (in about three
hours), to get five hours out of them.

Quoted message said:

I think what they really mean is the LED light is
equivalent in brightness to a typical 10-watt
halogen light.

From my experiments with bike lights, I'd say there seems
to be about a two-to-one ratio of apparent brightness
between LED and halogen lights, so the 5-watt LED may
well look as bright as a 10-watt halogen.

luxeonstar.comsub category.phpOpen ↗

For a *real* 10w equivalent LED headlight, see
nova-factory.comheadlight.htmlOpen ↗. Not cheap though.

Nick

"JamesE" <[email hidden]> wrote in message
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Quoted message said:

The new Summer Performance catalog is featuring their new
"ViewPoint GEN3" single Luxeon LED headlight. They claim
"10 watts plus" coming out of 4 AA NiMH batteries that run
5 hours. There's a "Digital" model with 6 power modes and
5 flashing modes ($140) and a "Non-Digital" model that
runs 8 hours on "high" and 4 day on "low" ($60). The
lights are made by Nite

Hawk.

Quoted message said:

I think what they really mean is the LED light is
equivalent in brightness to a typical 10-watt halogen
light. By my math 4 NiMH AA at 1.2 volts each will put out
about 0.4 amps for 5 hours, which is really about 2 watts
of power.

Watts, in this application, is a unit of heat dissipation.
The average LED at maximum brightness produces about 1.4
milliWatts. You'd need over 7000 LED's to produce 10 Watts.
Another draw-back is the light produced by an LED is very
directional. The trick designers use to make them good
headlights is reflector and lense design. I've got a Cateye
Opticube and I love it. The other posts had it right about
rating output in Watts as deceptive. They should rate them
by lumens or candlepower.

LAN Support <[email hidden]> wrote in message news:40ba71e4$0$58512$c30e37c6@lon-
reader.news.telstra.net...

Quoted message said:

For a *real* 10w equivalent LED headlight, see nova-nova-Open ↗
factory.com/headlight.html. Not cheap though.

Nick

"JamesE" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

The new Summer Performance catalog is featuring their
new "ViewPoint

GEN3"

Quoted message said:

Quoted message said:

single Luxeon LED headlight. They claim "10 watts plus"
coming out of 4

AA

Quoted message said:

Quoted message said:

NiMH batteries that run 5 hours. There's a "Digital"
model with 6 power modes and 5 flashing modes ($140) and
a "Non-Digital" model that runs 8 hours on "high" and 4
day on "low" ($60). The lights are made by Nite

Hawk.

Quoted message said:

I think what they really mean is the LED light is
equivalent in

brightness

Quoted message said:

Quoted message said:

to a typical 10-watt halogen light. By my math 4 NiMH AA
at 1.2 volts

each

Quoted message said:

Quoted message said:

will put out about 0.4 amps for 5 hours, which is really
about 2 watts

of

Quoted message said:

Quoted message said:

power.

El Calaverada said:
"Watts, in this application, is a unit of heat dissipation.
The average LED at maximum brightness produces about 1.4
milliWatts. You'd need over 7000 LED's to produce 10 Watts.
Another draw-back is the light produced by an LED is very
directional. The trick designers use to make them good
headlights is reflector and lense design. I've got a Cateye
Opticube and I love it. The other posts had it right about
rating output in Watts as deceptive. They should rate them
by lumens or candlepower."

P = IE
Power equals current in amps times Voltage in Volts.
Heat disapation isn't part of the equation.
There are many different rated Light Emitting Diodes... some up to 5 Watts. Since they disapate very little heat, most of the energy is radiated in light.
Yes, designers need to make the reflector aim the light in a most useful pattern. Lumens or candlepower can help understand the light output, but you also need to know the intensity across the pattern.... like a pencil beam or a wide angle beam.

daveornee said:

P = IE Power equals current in amps times Voltage in
Volts. Heat disapation isn't part of the equation.

Unfortunately it is very much part of the equation. Even the
best LEDs are not much more efficient than high-efficiency
filament lamps and to a first approximation all of their
power input is given out as heat.

One of the reasons there has just been such a quantum leap
in LED light output, is that in newer LEDs, the LED die
(semiconductor part) is mounted on a metal die that conducts
heat away from the die much more efficiently than can happen
in old-style plastic-packaged LEDs that we are so familiar
with. They still have a plastic window to let the light out,
of course. New LEDs typically need to be mounted on metal
heatsinks - like power transistors.

Quoted message said:

There are many different rated Light Emitting Diodes...
some up to 5 Watts. Since they disapate very little heat,
most of the energy is radiated in light.

Red LEDs are typically much brighter than green LEDs with
the same wattage, even though our eyes are more sensitive to
green - yellow light.

AC

Is there really such a thing as a 5 Watt LED? What materials
are they made from? Has someone come up with a new junction
material capable of producing 5 Watts without applying a
huge current? I haven't been involved in design in quite a
while, now I'm curious.

anonymous coward <[email hidden]> wrote in
message
"]news:[email hidden]...

Quoted message said:

daveornee said:

P = IE Power equals current in amps times Voltage in
Volts. Heat disapation isn't part of the equation.

Unfortunately it is very much part of the equation. Even
the best LEDs are not much more efficient than high-
efficiency filament lamps and to a first approximation all
of their power input is given out as heat.

One of the reasons there has just been such a quantum leap
in LED light output, is that in newer LEDs, the LED die
(semiconductor part) is mounted on a metal die that
conducts heat away from the die much more efficiently than
can happen in old-style plastic-packaged LEDs that we are
so familiar with. They still have a plastic window to let
the light out, of course. New LEDs typically need to be
mounted on metal heatsinks - like power transistors.

Quoted message said:

There are many different rated Light Emitting Diodes...
some up to 5 Watts. Since they disapate very little
heat, most of the energy is radiated in light.

Red LEDs are typically much brighter than green LEDs with
the same wattage, even though our eyes are more sensitive
to green - yellow light.

AC

El Calaverada said:

Is there really such a thing as a 5 Watt LED?

Yes - look up www.lumileds.com and www.roithner-
lasertechnik.de

Quoted message said:

What materials are they made from?

Pretty much the same materials as the old LEDs. One point is
that these LEDs actually contain multiple junctions on each
die. So in one sense they're parallel LEDs. I think the
major innovations are in the packaging and thermal
management.

Quoted message said:

Has someone come up with a new junction material capable
of producing 5 Watts without applying a huge current?

No... LEDs used to use such a small current, because their
light output was quite low. They were bright enough to see,
but not bright enough to be seen by... Now that they produce
a lot of light, they use a lot of current to match. Power
(watts) = Volts x Amps. 'owt for nowt, alas.

Quoted message said:

I haven't been involved in design in quite a while, now
I'm curious.

They will take over the world. (I use them, but have no
connection with the company).

AC

Quoted post said:

Originally posted by Anonymous Cowar

BOn Tue said:

P = IE Power equals current in amps times Voltage in
Volts. Heat disapation isn't part of the equation.

Unfortunately it is very much part of the equation. Even the
best LEDs are not much more efficient than high-efficiency
filament lamps and to a first approximation all of their
power input is given out as heat.

One of the reasons there has just been such a quantum leap
in LED light output, is that in newer LEDs, the LED die
(semiconductor part) is mounted on a metal die that conducts
heat away from the die much more efficiently than can happen
in old-style plastic-packaged LEDs that we are so familiar
with. They still have a plastic window to let the light out,
of course. New LEDs typically need to be mounted on metal
heatsinks - like power transistors.

Quoted message said:

There are many different rated Light Emitting Diodes...
some up to 5 Watts. Since they disapate very little heat,
most of the energy is radiated in light.

Red LEDs are typically much brighter than green LEDs with
the same wattage, even though our eyes are more sensitive to
green - yellow light.

AC [/B]

P = I*E are all electrical terms that do NOT include heat in the equation. The input power... power required from the source is measured in Watts. You arrive at the input power by multiplying Volts times Amps. The frequency of the light and human perception of the brightness are also important, but not part of the input power equation. Distribution of the light is also important, but not part of the input power equation.
Point taken on LED efficiency compared to incandescents, and the need to disapate heat.
Light output and heat disapation are very important, but not part of the equation.... that's my point.
I stand ready for more "illumination" on the subject.

AC, Thank you for the info. Take care -

anonymous coward <[email hidden]> wrote in
message
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Quoted message said:

El Calaverada said:

Is there really such a thing as a 5 Watt LED?

Yes - look up www.lumileds.com and www.roithner-
lasertechnik.de

Quoted message said:

What materials are they made from?

Pretty much the same materials as the old LEDs. One point
is that these LEDs actually contain multiple junctions on
each die. So in one sense they're parallel LEDs. I think
the major innovations are in the packaging and thermal
management.

Quoted message said:

Has someone come up with a new junction material capable
of producing 5 Watts without applying a huge current?

No... LEDs used to use such a small current, because their
light output was quite low. They were bright enough to
see, but not bright enough to be seen by... Now that they
produce a lot of light, they use a lot of current to
match. Power (watts) = Volts x Amps. 'owt for nowt, alas.

Quoted message said:

I haven't been involved in design in quite a while, now
I'm curious.

They will take over the world. (I use them, but have no
connection with the company).

AC