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Originally Posted by mollydog
Are you saying each "Cree" light puts out 3600 lumens? Or is it 3600 combined for all three?
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CREE is a superconductor manufacturer near the forefront of LED technology. They currently commercially produce industry leading 10w LEDs ( http://www.cree.com/~/media/Files/Cr...g/XLampXML.pdf) that produce 1000 lumens per 10W LED.
You will never get 3600 lumens of useful visible white light out of 10 watts ... its not even physically possible. The physical limit of efficiency for white light is about 260 lumens per watt. That assumes your light source is 100% efficient (produces ZERO heat and ZERO emissions in the non visible spectrum, and a perfectly even spread of colours in the visible spectrum).
BTW ... LEDs DO produce heat, thats why they have a big heat sink and cooling fins at the back of them. The only thing that even comes close to the physical limit of efficiency for light production is low pressure sodium HIDs (often used in street lighting) that can produce 160-180 lumens per watt.
The top commercially available LEDs currently put out around 100 lumens per watt. HIDs as used in headlights (Metal Halide) put out about 90. Halogen put out about 25-30 lumens per watt. Old Skool tungsten bulbs make about 15 lumens per watt.
3600 lumens from even 3 CREE LEDs is not credible when CREE themselves say each of their 10W LEDs makes 1000 lumens, not 1200 (see link above).
For more on luminous efficiency / efficacy, see http://en.wikipedia.org/wiki/Luminous_efficacy
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