Re: [APD] LEDs once more

[Jerry Baker <jerry at bakerweb_biz>]

Stuart Halliday wrote:
> I believe Jerry Baker wrote this email section below:
>> TBarber wrote:
>>> Good points.............he didn't also mention the heat output compared to
>>> metal halide.   I avoid metal halide for this reason.    Some aquarists
>>> would pay for a superior light ..........I will pass this along.  Not sure
>>> if we account for the majority of aquarists.
>> If you haven't dealt with high-power LEDs, I can tell you that they are 
>> very hot. The reason all high-power LED flashlights are aluminum is to 
>> act as a heatsink. The whole body of the lights can get up to over 
>> 100°F, and that's just for a couple hundred lumens.
> 
> Metal halides get hot too.
> These LEDs give off 1.1W each so not a huge heatsink required.
> A simple fan mounted above them is all that is required, not rocket science.
> Heatsink temperature control is a very mature technology.
> 
>> Also, the price of LED, even when factoring in its long life, is still 
>> much higher than HID or fluorescent. The technology will mature 
>> eventually, but it's not there yet.
> 
> But according to the prices today they already seem cost effective.
> Did you read my posting on this? :-)

Yes, I read it, but the prices are not correct.

See: http://fins.actwin.com/aquatic-plants/month.200709/msg00049.html

Current cost of the referenced LEDs is about 0.16 cents per thousand
lumen hours, but the cost of typical CF bulbs (assuming 5,000 hours) is
0.08 cents per thousand lumen hours. The initial investment in LED
emitters is very high at $370 for the equivalent of a 55-watt CF, but
they will last for about 11 years on a 12-hour day cycle. By then LED
manufacturers expect to achieve near theoretical limits of efficiency at
around 300 lumens per watt.

REFERENCES

Spectrum of Atlas LED NT-42D1-0425 (Daylight)
http://farm2.static.flickr.com/1384/1351994314_bd913518a7_o.png

Atlas LED Data Sheet
http://www.ledsupply.com/docs/Atlas.pdf

Atlas LED Prices
http://www.ledsupply.com/bl-nt-42d0-0426.php

CF lumen ratings
http://www.ahsupply.com/bulbs.htm

_______________________________________________
Aquatic-Plants mailing list
Aquatic-Plants at actwin_com
http://www.actwin.com/mailman/listinfo/aquatic-plants