Cree CXA analysis

SupraSPL said:
Unfortunately the 630nm 660nm chips we have are getting outdated. They are 38-40% efficient and cost $6/PAR W, but the CXA3070 3000K Z2 is 48% efficient at $6/PAR W. The AB bin is 55% efficient at $6/ PAR W. So for now, 3000K is the best bet we have available to us IMO.
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Don't you think the
 
But if we leave the invested $ out of the equation, don't you think the high photosynthetic activity of the reds could make up for their poor efficiency? Guess it depends on how much you value the green and yellow spectrums from the whites.. I've read a bit your and stardustsailors writings about carotene, lutein etc., but find it hard to tell how much green/yellow that actually is well utilized by MJ. If 5000+3000k gives an unnecessary abundance in the middle- spectras thats also a sort of waste.. Ok. I'm opening a lot of doors here and understand if it's hard to give a short answer.
 
So lets say you were allotted a certain amount of $ to build a lamp, at the end of the day the lamp built with the 3000K will beat the lamp that used the 5000K + reds. You could use the extra capability of the 3000K to increase overall yield or to increase overall efficiency, or both. In other words, there is no way to leave the invested $ out of the equation unless you already have the components on hand, and in that case I say, use what you have. So if one LED comes along and can match the efficiency of another, but is cheaper, then you can afford to run it softer and create a superior lamp.

As long as the spectral distribution is in good balance for flowering, all wavelengths will be used very efficiently by the plant and you can just crank it up. If red LEDs improved significantly, then we might have a case for 5000K + red + deep red and we might be able to make a flowering lamp superior to the best 3000Ks.
 
I really don't know wtf I'm talking about, I've only been looking at LEDs for a few days. Just a simple observation from your charts. The spectral intensity of 5k and reds would be superior in useable light produced and therefore more effecient, but the 3k is cheaper and easier to build since you only have to worry about one driver type.

The 3k negates one of the major benefits of LEDs, being able to produce light on the specific bands plants need to grow. It essentially acts as a better HPS, just bathing plants in huge amounts of light most of which it can't use. Or at least wouldn't be able to compare with the high spikes of spectral intensity from using LEDs on plant-specific spectrums.
 
If you're only looking for efficiency and don't care about the cost I think you could leave the $ out of it.. Probably a bit stupid, but reasons I can think about is beeing more environment friendly or wanting to break your gram/watt record no matter the cost..

There is a an old thread on another forum where a "mrX" gets 2 G/W with 30% 10000K and 70% 630nm. I almost find it hard to believe, but the guy seems honest.. So I really don't know what to think.

I know that you have so much more knolwledge and practical experience than me, so I'm absolutely not calming to have a better recipe for success! Actually starting to doubt my choice of cobs right now. I bought 8 4000 K cree 2530 because they emitted 140 l/watt, instead of buying 3000K's that emitted 129 l/w. My logic told me that adding a few high binned 630-660 nm 3 watter would give me a better spectrum with about the same l/w output.. More total cost and more hassle. That's for sure, but I said to my self that it was worth it.. Will probably drive the the cobs at 300-500 mA instead of 800, hoping that it will leave me with 150-160 l/w..

Would have been a bit cleaner to only have white cobs, with no "tweak-the-spectrum-reds", so that's another reason to just go with the 3000K..
 
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AirAnt said:
If you're only looking for efficiency and don't care about the cost I think you could leave the $ out of it..
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If your design criteria was aiming for efficiency, you would still have to take cost into account to find out which COB would allow you to achieve the maximum. The CXA3070 3000K AB bin running at 300mA (10W) is 54.9% efficient and cost $6.81/ PAR Watt. So you really could build a working flowering lamp and get cheap drivers with very high efficiency. Unfortunately the ABs are scarce at the moment but you can get CXA3590 3000K BD bin. If you ran them at .25A (17W) they would be 50% efficient and cost $6/ PAR W, cheap drivers are available so it really could be done.

Fiveleafsleft said:
There is a an old thread on another forum where a "mrX" gets 2 G/W with 30% 10000K and 70% 630nm. I almost find it hard to believe, but the guy seems honest.. So I really don't know what to think.
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I remember Mr X. All I can say is, if he was able to pull 2gr/W with those no name LEDs (15% efficient) he can pull 6 gr/W with COBs that are 45% efficient :)

Fiveleafsleft said:
I know that you have so much more knolwledge and practical experience than me, so I'm absolutely not calming to have a better recipe for success! Actually starting to doubt my choice of cobs right now. I bought 8 4000 K cree 2530 because they emitted 140 l/watt, instead of buying 3000K's that emitted 129 l/w. My logic told me that adding a few high binned 630-660 nm 3 watter would give me a better spectrum with about the same l/w output.. More total cost and more hassle. That's for sure, but I said to my self that it was worth it.. Will probably drive the the cobs at 300-500 mA instead of 800, hoping that it will leave me with 150-160 l/w..

Would have been a bit cleaner to only have white cobs, with no "tweak-the-spectrum-reds", so that's another reason to just go with the 3000K..
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I didn't know Mr.X but found the original thread here. He's using a SoG with low intensity lighting, which is a good way to get a high GPW. His results look perfectly credible to me.

About the efficiency of no name LEDs, in my experience they do a lot better than 15%, typically around 30%. Here's a picture of a very crude caloric measurement that I did last year
IMG_5704.jpg
The light from the LED heats up a black target and the temperature of that target is then measured. It's calibrated against a halogen bulb of known wattage.
 
SupraSPL said:
If your design criteria was aiming for efficiency, you would still have to take cost into account to find out which COB would allow you to achieve the maximum. The CXA3070 3000K AB bin running at 300mA (10W) is 54.9% efficient and cost $6.81/ PAR Watt. So you really could build a working flowering lamp and get cheap drivers with very high efficiency. Unfortunately the ABs are scarce at the moment but you can get CXA3590 3000K BD bin. If you ran them at .25A (17W) they would be 50% efficient and cost $6/ PAR W, cheap drivers are available so it really could be done.
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That was/is my wet dream! But even the z4's are hard to find if you don't wanna buy 20 of them.. My choice stood between 2 3590 or 8 smaller cobs. The 2530's costed me 22$ So it allowed me to have more of them for the same price, with decent efficiency, and better coverage and spread.. (ok, $ matters a bit to me to) Think going with several light driven cobs is a good choice in my small cabinet 1,5x3 f. maybe 4000k wasn't the optimal spectrum.. they look pretty good par-efficiency wise when i study the analyses provided by MrFlux.. But more reading tells me they lack a bit in the far red spectrum compared to 3000k.. (not so much in 630)

We'll see how the lights perform. My current plan is to supplement with ≈ 7% 630nm in early bloom and ≈15% 630-660nm after stretch has stopped. Feel free/please criticize my choice of spectrum if you feel for it.

My research tells me MrX used evoled, and that they used high quality cree leds at the time... But still sounds a bit to good to be all true.. I agree on that.. I don't know if it's allowed, but i can post a link to the thread if it is.
 
MrFlux said:
I didn't know Mr.X but found the original thread here. He's using a SoG with low intensity lighting, which is a good way to get a high GPW. His results look perfectly credible to me.

About the efficiency of no name LEDs, in my experience they do a lot better than 15%, typically around 30%. Here's a picture of a very crude caloric measurement that I did last year
View attachment 3192377
The light from the LED heats up a black target and the temperature of that target is then measured. It's calibrated against a halogen bulb of known wattage.
Click to expand...

I have read in that thread that it was a Chinese product, I can hardly believe it. This is the link they posted: http://www.alibaba.com/product-detail/90W-LED-Grow-light-EVO-light_503317672.html.
 
Yes mr x grows where awesome..........but unfortunately not legit according to the Spanish forums?? still can't find the link or proof of that anymore........was a loooong time ago. Hope someone can correct me if I'm wrong, don't wanna spread misinformation.

He used the real EVO v1 not some chinese clone..........I think the original spanish company went under after the evo V3 "starlight" fiasco.
 
guod said:
those no name LEDs have a name
Cree XP-E red 630nm.Cree XP-E cool whiteView attachment 3192358
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The grow I was referring to was on Cannabis Cafe 2009-2010 and he was using chinese no-namers (UFOs etc) with white russian and chronic and claimed 1.7 - 2 gr/W. That must have been before he tried the EVO.
http://www.420magazine.com/forums/completed-journals/105950-led-grow-test-35.html#post943071

MrFlux said:
About the efficiency of no name LEDs, in my experience they do a lot better than 15%, typically around 30%.
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I would not be surprised to see 30% efficiency in generic blues, but not in the reds or whites (at operating temp).

Back in those days we were using the best OSRAM golden dragon plus that KNNA could find and running them soft ~500mA. 26% was the best we could do (at operating temp). Our blues were about 38%, the whites were about 23% and our 630 reds were 26%. At the time the best whites were the Cree XRE Q5 bin 6500K and they were only about 25%. So you can imagine what kind of efficiency those generic LEDs must have been running at, 15% was probably being generous. The lower the efficiency, the hotter they run, lowering efficiency further. So that is why I claim, if Mr X can do 2gr/W with generic 2009, he should be able to triple that with modern COBs.

I continued to use those old golden dragons as vegging lamps and only retired them this year. They got updated with golden dragon 660nm when we finally got them in top bins.
DSC06872a.jpg
 
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SupraSPL said:
So that is why I claim, if Mr X can do 2gr/W with generic 2009, he should be able to triple that with modern COBs.
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That seems logical. Taking this a bit more general, one would expect the GPW that ppl get to be somewhat following Haitz's law. But somehow this doesn't happen. It's a bit of a mystery to me why. Why aren't we seeing spectacular GPW's today.
 
MrFlux said:
That seems logical. Taking this a bit more general, one would expect the GPW that ppl get to be somewhat following Haitz's law. But somehow this doesn't happen. It's a bit of a mystery to me why. Why aren't we seeing spectacular GPW's today.
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Could it be that most of us are more limited by space than electricity and keep jamming in the same watts per square meter in order to get the most out of our spaces. Maybe we are therefore seeing more THC and better quality instead of more gr/w. As you said growing Sog with more low intense light probably is the way to go to maximize gr/w. If you wanna maximize yield per plant/space more, on the other hand.. BRIGHT LIGHT!
 
SupraSPL said:
-increased electric bill due to reduced efficiency
-finding a 1950mA driver at a competitive price. We have access to cheap 700, 900, 1050 and 1400mA drivers but nothing above that (yet)
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Thank you Supra. I agree about efficiency.
1950 mA might be tough to get, I like that 3590 needs less current and more voltage. may be the drivers will be cheeper for 3590 after a while.
See attached comparison for 3590 at 0.6A and 1.4A.
If you get $100 2 * 3590 at 0.6A a or $50 1 *3590 at 1.4A you will get same light output.
Using lower current and 2 chips we can save $26 in power each year. It will pay for itself in 2 years.
If you consider extra cost of double heatsink, double power etc you will still likely breakeven at 4-5 years.
BUT you are right using 2 piece underpowered designed it will increase the lifetime. But then CREE will have better emitters and we young generation like to play with new stuff
I guess its a matter of choice. Ideally current should be variable so that you can use it anywhere between 0.7 to 1.4Amps
Question: When you choose constant current driver. Do i just look at Watts, Voltage around Vf and Current (as desired)
Or should i look for anything else. Thank you

Got 3590 efficiency from your thread Supra. Not sure where did you find this.
Also 1 watt running 14hrs a day for 365 days at 0.20 cents per killo watt is Aprox$1 per year
CXA3590.png
 

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To clarify what I meant about needing more heatsink and driver to do the same job, at first glace it seems like design 1 would cost more because you need twice the heatsinks and twice the drivers, but because design 2 is dissipating 112W, it needs even more heatsink surface area than design 1. That extra expense would have to be deducted from the cost of design 1 up front cost. The same goes for the drivers, a 25% increased up front cost for design 2 in order to match the productivity of design 1. So once you take that into consideration, the electrical savings of design 1 pays for its up front cost much sooner.

On a larger scale, air conditioning and ventilation come into play making it even more in favor of running soft. Choosing drive current for a DIY build can be tricky business. For the CXA3070 I like everything between 700mA and 1400mA. For the CXA3590 I like 350-700mA.
 
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If you choose to put the different low-driven cobs on several smaller heat sinks, you would also have the advantage of better spread, coverage and flexibility. I think that having all your plants in optimal distance from the light source can be a tremendous advantage... Maybe not worth the extra hassle if you're running a really big grow op, but for the small scale enthusiast it could actually be a part of the fun!
 
I agree. Funny how all this stuff comes into consideration just from choosing your drive current. This is also the reason why I suspect the CXA3590 might over concentrate the power for a 115 degree beam angle. Some of my (25W) CXA3070s are only 6" from the canopy. It is more work to keep them in close but it is well worth the effort IMO. When it comes down to it, I only spend an hour or 2 on canopy management each cycle.
DSC07351a.jpg
 
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