Why are Cree LEDs considered the best?
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swannyson7
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Lower kelvin rating lighting spectrum is ideal for growth, although it isn't appealing to the eye. When offset by the blue diodes at a 1:1 ratio, you will get about a 12-14k look and 2 blue:1 white ratio will yield about a 20k spectrum. I think they are considered the best because they are tried and true, versus many of the new companies that don't have enough use under their belts to be fully trusted.
Troylee
all about the diy!!!!!
Its a long drawn out process but Cree have the most lumen per watt Or something along those lines it made it best for heat, waisted energy etc... Pretty much Cree are the most efficient and best for the buck bang you can buy... I read a big debate about it long ago maybe I kind find it again lol...
Hahnmeister
Active Member
The K ratintgs are usually marketing terms, in particular when talking about Halies and T5's. Often times the CCT is not what the maker says it is because of their own desire to appeal to a certain market. LED's are more efficient the bluer they are, but they are trying to appeal more to the home lighting crowd, so they dont want to mark them as any bluer than they have to. Halides made for the reefing crowd wanted to be bluer, so they named them things like 20,000K or even 50,000K, values that dont really exist (the CCT scale tops out at 10,000K). The Kelvin rating or CCT is an attempt to sum up a three-dimensional or 3-axis plot of Red, Green, and Blue axes known as the CIE scale with a number that represents a point on a 2-d line (Red to Blue). There are obvious problems with this since you lose some detail of how much there is of each color your eye can see.
To further complicate things, your eyes are not the best means to measure what the corals "see" (lumen or photometric scale), and they are sensitive to specific frequencies that cant be represented in any way other than an actual spectral graph (radiometric or "PAR" scale). This way, you can make sure that that a very blue looking light actually has that actinic 410-420nm spectrum that you wouldn't otherwise be able to tell apart from a light that just makes alot of blue and red. Trying to sum up every little spike and spectrum of a light source with a single number, or even three coordinates is a bit like saying that since an car took 1 hour to travel 60 miles, it must be travelling 60mph the whole time. In a similar way, two lights may really be 5000K, yet have totally different spectral outputs.
Color temperature - Wikipedia, the free encyclopedia
CIE Lab: Information from Answers.com
As for Cree, well, they have the highest lumen output per watt of any maker for daylight LED's, up to 160 lumens per watt, and conidering how much the lumen scale neglects blue spectrums compared to red and green, the PAR or blue outputs of LED's may scale much higher than other technologies since it is more efficient in the blue spectrums (much like T5's). The lumen scale, based on how our eyes see light, weighs the light with about 40-50 percent of our cones being sensitive to first green, then red, and only about 10% are sensitive to blue. Considering the efficiency of the optics as well compared to the reflectors used to deliver halides, T5's, and other radial or linear bulbs (a led's lens can easily hit 85% efficiency, sometimes as high as 95% while an everyday halide reflector will often lose more than 40% of the bulbs output, sometimes as high as 60% when you add in corrosion and deposits. Next look at the efficiency of halides in general, a 250watt ushio 10-14,000K puts out only about 42 l/w, and a 20,000K puts out half of that at 20l/w. Sure, halides CAN hit just over 100 l/w, and T5HO about 85, but NOT the spectrums reefers use! So between comparing the delivery system & optics (lens or reflector) and the ACTUAL efficiencies of LED's and other technologies, LED's are the easy winner even with efficiencies like the 80 lumens per watt for the Edistar LED's in the Photon Cannons. Then add in how fast a halide (in particular a bluer one) dims over a year (its not unusual to have a 20,000K as low as 10 lumens/watt after a year, even worse if say, a probe start bulb on a HQI ballast)compared to the 70% drop that LED's will have over 10 years, and its not hard to say even some less efficient LED's may still be worth it.
HERO-LED 50 Watt High Power BLUE Led 1000 Lumen [50WHPL-B] - $79.50 : Led Strips Hero-ledstore.com
HERO-LED 50 Watt High Power Led Cold White 12000K 4000 Lumen [50WHPL-12K] - $79.50 : Led Strips Hero-ledstore.com
HIGH POWER 50W WHITE 12000K LED LAMP 4000-4500LM 24-26V HIGH POWER 50W WHITE 12000K LED LAMP 4000-4500LM 24-26V [LD50W4500120-W12K] - US$45.00 : LED-DNA
I know other places that sell that chip for less than $50... as long as you can cool that sucker its a great DIY!
To further complicate things, your eyes are not the best means to measure what the corals "see" (lumen or photometric scale), and they are sensitive to specific frequencies that cant be represented in any way other than an actual spectral graph (radiometric or "PAR" scale). This way, you can make sure that that a very blue looking light actually has that actinic 410-420nm spectrum that you wouldn't otherwise be able to tell apart from a light that just makes alot of blue and red. Trying to sum up every little spike and spectrum of a light source with a single number, or even three coordinates is a bit like saying that since an car took 1 hour to travel 60 miles, it must be travelling 60mph the whole time. In a similar way, two lights may really be 5000K, yet have totally different spectral outputs.
Color temperature - Wikipedia, the free encyclopedia
CIE Lab: Information from Answers.com
As for Cree, well, they have the highest lumen output per watt of any maker for daylight LED's, up to 160 lumens per watt, and conidering how much the lumen scale neglects blue spectrums compared to red and green, the PAR or blue outputs of LED's may scale much higher than other technologies since it is more efficient in the blue spectrums (much like T5's). The lumen scale, based on how our eyes see light, weighs the light with about 40-50 percent of our cones being sensitive to first green, then red, and only about 10% are sensitive to blue. Considering the efficiency of the optics as well compared to the reflectors used to deliver halides, T5's, and other radial or linear bulbs (a led's lens can easily hit 85% efficiency, sometimes as high as 95% while an everyday halide reflector will often lose more than 40% of the bulbs output, sometimes as high as 60% when you add in corrosion and deposits. Next look at the efficiency of halides in general, a 250watt ushio 10-14,000K puts out only about 42 l/w, and a 20,000K puts out half of that at 20l/w. Sure, halides CAN hit just over 100 l/w, and T5HO about 85, but NOT the spectrums reefers use! So between comparing the delivery system & optics (lens or reflector) and the ACTUAL efficiencies of LED's and other technologies, LED's are the easy winner even with efficiencies like the 80 lumens per watt for the Edistar LED's in the Photon Cannons. Then add in how fast a halide (in particular a bluer one) dims over a year (its not unusual to have a 20,000K as low as 10 lumens/watt after a year, even worse if say, a probe start bulb on a HQI ballast)compared to the 70% drop that LED's will have over 10 years, and its not hard to say even some less efficient LED's may still be worth it.
HERO-LED 50 Watt High Power BLUE Led 1000 Lumen [50WHPL-B] - $79.50 : Led Strips Hero-ledstore.com
HERO-LED 50 Watt High Power Led Cold White 12000K 4000 Lumen [50WHPL-12K] - $79.50 : Led Strips Hero-ledstore.com
HIGH POWER 50W WHITE 12000K LED LAMP 4000-4500LM 24-26V HIGH POWER 50W WHITE 12000K LED LAMP 4000-4500LM 24-26V [LD50W4500120-W12K] - US$45.00 : LED-DNA
I know other places that sell that chip for less than $50... as long as you can cool that sucker its a great DIY!
Last edited:
greg0385
Valuable Member
does everybody here still think that they may not last 10years? i know that most people that are using them are using them with a dimmable driver set at like70% power. im waiting on more growth info and a little more time to see if they get cheaper or if the leds fail over a longer time.
greg
greg
wld1783
Well-Known Member
The Crees are considered the best because of their Cool White Spectrum. This is my opinion based on Sanjays MH testing and spectral analysis of numerous MH Bulbs compared to numerous LEDs....This information allows us to duplicate almost any MH Bulb with LEDs.
Most suppliers of the Cree LED will not specify or provide an aquarium beneficial Bin. Also The quality on which the LED is mounted on stars or strips varies greatly. I've found that the Domestic Manufacturers offer the best quality and provide the Bin of the LED at only a slightly higher cost....Along with English proficiency it is well worth it to stay domestic.
With out a bin your Cool White or Royal Blue "is like a box of chocolates"...."You dont know what you will get."
Here are a few PDFs from Cree that may help.
http://www.cree.com/products/pdf/xlamp7090xr-e_b&l.pdf
http://www.cree.com/products/pdf/xlamp7090xr-e.pdf
http://www.cree.com/products/pdf/XLampXP-E.pdf
Bill
Most suppliers of the Cree LED will not specify or provide an aquarium beneficial Bin. Also The quality on which the LED is mounted on stars or strips varies greatly. I've found that the Domestic Manufacturers offer the best quality and provide the Bin of the LED at only a slightly higher cost....Along with English proficiency it is well worth it to stay domestic.
With out a bin your Cool White or Royal Blue "is like a box of chocolates"...."You dont know what you will get."
Here are a few PDFs from Cree that may help.
http://www.cree.com/products/pdf/xlamp7090xr-e_b&l.pdf
http://www.cree.com/products/pdf/xlamp7090xr-e.pdf
http://www.cree.com/products/pdf/XLampXP-E.pdf
Bill
wld1783
Well-Known Member
Thermal Management is key....If they get too ho they will not last.
You can drive them full....most dont (700mA works for most) just keep them cool.
Bill
Hahnmeister
Active Member
From the OSRAM Laboratory: Efficiency Record for Warm White — LED professional - LED Lighting Technology and Design for LED, LEDs, OLED, OLEDs Lighting Applications
Sylvania/OSRAM isnt really behind, they are just going after a larger market.
Sylvania/OSRAM isnt really behind, they are just going after a larger market.
wld1783
Well-Known Member
Nice for street lights...True a much larger market...
Most consider 6.5K the lowest for the marine environment. Past 30 Feet most of the warmer spectrum is blocked.
LEDs, their colour and their efficiency is rather complex. Given a specific LED....Say the Cree XR-E Royal Blue, you have specific Bins which change the colour slightly.
The Q5 Cool White has many bins which greatly affect looks.
http://www.cree.com/products/pdf/xlamp7090xr-e_b&l.pdf
IMHO its best to use what has provided good growth and looks.
Bill
Most consider 6.5K the lowest for the marine environment. Past 30 Feet most of the warmer spectrum is blocked.
LEDs, their colour and their efficiency is rather complex. Given a specific LED....Say the Cree XR-E Royal Blue, you have specific Bins which change the colour slightly.
The Q5 Cool White has many bins which greatly affect looks.
http://www.cree.com/products/pdf/xlamp7090xr-e_b&l.pdf
IMHO its best to use what has provided good growth and looks.
Bill
Hahnmeister
Active Member
Well, I just wanted to make the point that Cree isn't always the best. For Royal Blue LED's, the Luxeon PRO2's seem the best. And for actinic, they dont even have an entry. But for LED's that are high efficiency AND of a spectrum that the reefers would like, it seems Cree is the way to go (for the primary light at least, maybe not blue and actinic).
