New 10-watt(?) LED Light

[JamesE]

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.

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.

Fuzzy marketing aside I'm eager to find out more about these lights. I mean
if they really do put out the same lumens as a 10w halogen with a good beam
pattern, and the GEN3's do it with only 4 AA's, then it's a light seriously
worth considering.

The GEN3 isn't on the Performance web page yet, nor is it mentioned on Nite
Hawk's. The non-digital model can be seen at Nashbar's site -- search for
"emitter."

[LioNiNoiL_a t_Ne t s c a pE_D 0 T_Ne T]

> 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.

> 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.

http://www.luxeonstar.com/sub_category.php?id=85

[Collin]

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.

http://www.caves.org/imo/pdf/Nova%20discharge.pdf

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.

http://www.caves.org/imo/pdf/NOVA%20instructions.pdf

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 wrote:
>> 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.
>
>> 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.
>
> http://www.luxeonstar.com/sub_category.php?id=85
>

[LAN Support]

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

Nick

"JamesE" > wrote in message
...
> 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.
>
> 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.

[El Calaverada]

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 > wrote in message
...
> For a *real* 10w equivalent LED headlight, see
> http://www.nova-factory.com/headlight.html. Not cheap though.
>
> Nick
>
> "JamesE" > wrote in message
> ...
> > 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.
> >
> > 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.
>
>

[daveornee]

El Calaverada said: "Watts, in this application, is a unit of hea
dissipation. The average LED at maximum brightness produces about 1.
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 tric
designers use to make them good headlights is reflector and lens
design. I've got a Cateye Opticube and I love it. The other posts had i
right about rating output in Watts as deceptive. They should rate the
by lumens or candlepower.

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


-

[anonymous coward]

On Tue, 01 Jun 2004 01:30:16 +0000, daveornee wrote:

> 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.

> 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]

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 > wrote in message
...
> On Tue, 01 Jun 2004 01:30:16 +0000, daveornee wrote:
>
> > 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.
>
> > 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

[anonymous coward]

On Tue, 01 Jun 2004 04:26:30 +0000, El Calaverada wrote:

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

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

> 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.

> 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.

> 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

[daveornee]

Anonymous Cowar wrote:
> On Tue, 01 Jun 2004 01:30:16 +0000, daveornee wrote:
> > 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.
> > 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


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


-

[El Calaverada]

AC,
Thank you for the info. Take care -

anonymous coward > wrote in message
...
> On Tue, 01 Jun 2004 04:26:30 +0000, El Calaverada wrote:
>
> > Is there really such a thing as a 5 Watt LED?
>
> Yes - look up www.lumileds.com and www.roithner-lasertechnik.de
>
> > 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.
>
> > 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.
>
> > 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
>