All of the data you guys see on these lights is true. I know that for fact. Soon Sanjay
will be coming out with an article on these lights, PAR and SED plots, etc.. That is all I
can say for now :-)

A good friend of mine is an electrical lighting engineer, who designs such a lighting
systems, who has built his own with similar results and comments. I have his unpublished
very, very, technical article explain it all, which may appear in one of our on-line reef
magazines; the array, type of LED's circuit designs, power supplies, outputs, cost, etc.

Solairs has been working on this lighting system for 2 years. I have had phone
conversations with the owner. TRA III has some discussions on advanced lighting system in
the works and reef lighting systems of the future, to include LED's. LED's are the future
of reef lighting.

--
Boomer

If You See Me Running You Better Catch-Up

Former US Army Bomb Technician (EOD)
Member; IABTI, NATEODA, WEODF, ISEE & IPS

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"atomweaver" wrote in message
...
: "Pszemol" wrote in :
:
: "atomweaver" wrote in message
: ...
: I cannot confirm the PAR or the equivalent lighting output, but the
: 50,000 hours service time is fairly accurate for LEDs.
:
: I would guess it will depend on the type of the LED,
: and on the condition it is used at (overcurrent, temperature).
: We had already a precedence where some moon-lights were
: worn prematurelly (less than a year) due to the manufacturer
: supplying them with cheapo, unreagulated power supply driving
: them at or above their maximal tolerable current values.
: Yes, they were very bright, but they did not last long...
:
:
: Sure. Poor engineering can _always_ overcome the most robust components
::-)
:
: LEDs will fail in a "full off" manner, meaning unlike the spectral
: decay you experience with MH or HO bulbs, you'll get the full power
: of the LEDs rught up until the day they die. This is both good and
: bad. Good, in that you'll get very consistent light, and an
: incredibly long service lifetime. Bad, in that some day when the
: lights _do_ fail, you'll have to scurry around for an interim
: lighting solution, whilst waiting for your replacement/ reconditioned
: LED (note, 50,000 hours at 16 hours lighting per day, means you'll
: have this problem once every 8.5 years, on average.)
:
: There are many different LED technologies and we do not know
: what type of LED are used in this fixture. I have seen already
: white LED made with the similar principle white fluorescent
: tubes are made: native LED spectrum is UV and the LED lenses
: are covered with white phosphors, re-emiting white light when
: they receive UV rays from the LED. I could only expect the same
: kind of decay of light spectrum and similar longevity with
: this kind of LEDs.
:
: You caught me! I assumed from the claim of 50,000 hours that this was a
: visible specrum semiconductor light array, assembled without the use of
: lenses (which, as you say, will degrade just like bulbs). Such would be
: the only tech I'm aware of which could make the claim of 50K hours of
: steady output. Still, its an assumption I shouldn't have made...
:
: Assuming a white LED is made on a different principle of mixing
: base colors to get white effect - with at least three different
: color LED chips inside one "bulb" I could not imagine how can
: you get properly spread light spectrum to imitate sun-light...
: You would rather get light with three or four (depending on
: number of led chips colors per bulb) peaks in the spectrum and
: not spread spectrum like incadescent or good HQI/MH fixtures give...
:
:
: I'd expect something more like 15-60 different selected wavelengths of
: output, and thus a more complete spectrum.
:
: Claims of low heat output from hese systems are accurate.
: The load demand on a chiller may be significantly reduced.
:
: Do you have any access to the efficiency of LED light data ?
: Do they really produce more light per Watt of electricity used than MH
: ?
:
: I know from direct experience how efficient they are in terms of an
: energy source for pushing industrial chemical reactions. Spectrum of
: output is much narrower than a standard bulb, but if the catalyst you
: want to have run your reaction happens to be efficient at absorbing
: light in the wavelength of output of the LED, then Yes, the LED source
: is much more efficient, watt for watt. Same goes for visible light,
: although the light fixtures are vastly too expensive at this point to be
: reasonable for replacing typical flourescent fixtures for human use
: (althoguh I don't doubt that they'll be the standard at some point in
: the future, if they can get their costs down).
: Being an industrial chemist, I don't know nearly enough about the
: active absorption wavelengths used photosynthesis to make that same
: assesssment of these lights for use in reef aquariums. The vendor claim
: of 178 PAR vs. 133 for a 250W MH source is a starting point, but that
: kind of measurement could be an inaccurate means of assessing an LED
: source.
:
: DZ