DiY LED - Cree CXA3070

RedCarpetMatches

Well-Known Member
I think I came across who you're talking about. He's killing it in a 4x4 with just a 315w Agro. He also has air pots with blue mats ;) I've always wondered about that combo, and he's the only one I've seen do it.

I plan on bare vert CMH, light mover, and 2700 COBs behind/above plants. Best of both worlds me thinks.
 

MrFlux

Well-Known Member
The 1.9 umol/J figure is including infrared and UV unless I misunderstand?
There is is no UV or IR included that figure, only from 400-700nm. Btw this is specified by Philips and not something that I calculated. I hope that the LED panel manufacturers will also start to publish their PPF figures because this makes it super easy to compare, also against totally different lighting technologies.

If our math is correct, the CXA3070 3000K Z2 bin at 900mA is 2.56 umol/J in the PAR range.
The CXA 3000K, top bin, at default current and 25C, is doing 1.73 umol/J in the PAR range. When running at half the default current there is about a 20% bonus, so it would become something like 2.08 umol/J. Which is insanely great.

Would it be possible to extract an LER from this data considering the PAR range alone:
It would be a bitch to digitize all the spikes... so would rather pass on this one :-)
 

SupraSPL

Well-Known Member
Gotcha they specified ppf, more helpful data than most lol. Although just like with radiometric efficiency, even with ppf we cannot make a direct comparison unfortunately due to the photosynthetic efficiency of the spectrum.

OK I think I see where I went wrong. I was using 6.29 umol/s and I should have been using 4.88. So if the radiometric efficiency of the 3000K CXA3070 mid bin @ 900mA Tj 50C is 40.7% then 4.88 * .407 = 1.986 umol/J

I dont blame you for wanting to pass on digitizing that. Too bad we dont have software that can handle that for us. Care to wager a guess at the radiometric efficiency of CMH in the PAR range? Based on the umol/S and the fact that the CMH has more violet and red, it seems you are correct, the efficiency of output may actually be similar when the cmh bulb is brand new. So at that point the only advantage the LED has is regarding reflector losses.
 

RedCarpetMatches

Well-Known Member
Gotcha they specified ppf, more helpful data than most lol.

To get the ppf figure for the currently available CXA3070, I used your earlier numbers for the CXA 3000K curve. I know most of the data does not apply but I thought the umol/S is specific to that curve.

CXA 3000K
Power in : 3.76 W (9.40V x 0.40A)
Luminous flux : 423 lumen
Efficacy : 112 lumen/W
LER : 328 lumen/W
Radiometric eff.: 34.3%
Radiant flux : 1.29 W
Photon flux : 6.29 umol/s

So I multiplied 6.29 X .407 (40.7% is the radiometric efficiency of the 3000K CXA3070 mid bin @ 900mA Tj50C) = 2.56 umol/J
Did I get that right?


I dont blame you for wanting to pass on that. Too bad we dont have software that can handle that for us. Care to wager a guess at the radiometric efficiency of CMH in the PAR range? Based on the umol/S and the fact that the CMH has more deep blue and red, my guess is 85% of the Cree mentioned above so 34%, same as HPS.
CMH is an indoor sun. Every run gives me a boost in potency, appeal, health, vigor, etc. I've tried all light (except induction) and love it all. Just can't beat a CMH IMO. Stats can be deceiving eh. I'd still like to add some extra 600/730 to my 860w CMH.
 

SupraSPL

Well-Known Member
Ya CMH + deep red seems like it would be the perfect flowering spectrum. I had to make a correction to the post you quoted to agree with Mr Flux, it seems like the radiometric efficiency of CMH when brand new really is similar to a 3000K CXA3070 Z2 running soft, very impressive numbers.
 

nestor

Well-Known Member
Hopefully one of you can help me with this. If I wanted to run a 4 cxa25XX @ 700mA each what kind of power supply would I need to run those chips in series? I'm trying to utilize a tiny amount of space and only have room for a single driver. I've looked at the inventronics, and while I like the simplicity I'm pretty sure it can done cheaper.
 

RedCarpetMatches

Well-Known Member
What would you guys recommend for 660nm supplementation in a vert grow. I'm a DIY type guy, so I'm trying to get it done cheap and simple. I was thinking the luxeons. Reflector or no is my big question. I want them close...around a foot above/angled behind. Any answers will be much much appreciated.
 

smokey the cat

Well-Known Member
What would you guys recommend for 660nm supplementation in a vert grow. I'm a DIY type guy, so I'm trying to get it done cheap and simple. I was thinking the luxeons. Reflector or no is my big question. I want them close...around a foot above/angled behind. Any answers will be much much appreciated.
iirc http://shop.stevesleds.com/Philips-Luxeon-ES-Deep-Red-3-Watt-LEDs-Luxeon-ES-Deep-Red.htm for $3.40 is as good as it gets atm, Steve certainly talks it up as the best red out there.
 

Positivity

Well-Known Member
That's what I've been using...the steves 660. They definitely get the job done

my 80 degree reflector had to be like 2' up, otherwise seems better with no reflector
 

RedCarpetMatches

Well-Known Member
Glad to read you guys are liking them. I will be supplementing my CMH, and the stars will be fairly close due to space. How many stars per foot? Will 700ma be too much, or should I drive them less. This is where the DIY confuses me.
 

Bueno Time

Well-Known Member
This thread is great. Over the last 2 days I read through the whole thread and have gained some good knowledge.

Last time I was looking into building a small DIY LED, there were only the stars available and the prices and searching for correct wavelengths in good bins drove me away. Now these COBs are pretty kick ass and seem so simple to setup. Im very close to buying a 3070 3000k and a driver to play with.

I was originally thinking about running the 3070 on a meanwell 60w 1400mA driver for about $23 but those $11 30w 900mA drivers being 90% efficient might be a good route and save a few dollars. I just feel like I would not BE getting as much as I can out of the relatively expensive $40 COB if I run it at a lower amperage. I know they are more efficient at lower amperages but if I was more concerned with output and wasnt particularly concerned with efficiency and just wanted to get a lot of output from a COB in a small space wouldnt it be better to run it at 1400mA instead of 900mA in my case? I would be building a small ~1 sq ft cab for the single 3070 COB experiment.

I have a nice CPU heat sink and plenty of fans and adapters to test different size fans at different voltages on the heat sink and I even have thermal paste already and all soldering tools and whatnot needed to build it so my only expense would be buying the cob and driver if I stick with just one COB for now to test it out (if I went with more than 1 COB I would need to purchase a larger heat sink or separate heat sinks).

If they were cheaper, I would get 4 COBs for my 1.5x2.5 ft tent that I currently run a 150hps in but I cant justify that cost yet to switch over to COBs in the tent especially since I tend to get ~100 grams from the 150hps per flowering cycle, I am not sure the cost to upgrade would be worth the results. I think having a smaller cab with a COB or two would be a lot of fun to play with though and a good test to see how many grams I get per sq ft with the COBs to see if it really might be worth it to spend $200 or more on converting the tent to LED.
 

Positivity

Well-Known Member
700ma seems fine to me. I like the brightness level they hit at that current

all ol my leds are just a inch or so apart...but my heatsink is beefy and the fans are fast. So I'd spread them a bit more otherwise..

wish I could give more exact numbers, maybe supra or someone will chime in. Still learning myself..
 

smokey the cat

Well-Known Member
Or for more satisfying tweaking get an lpf-60d from MeanWell for $33 odd bucks - and use it at a range of different outputs. :success: lol
 

SupraSPL

Well-Known Member
CXA3070 3000K Z2 bin:
43% @ 700mA
40.7% @ 900mA
39.42% @ 1050mA
36.6% @ 1400mA

Nothing wrong with running at 1400mA, you get almost twice as many photons for your dollar, but on the other hand you get 17.5% increase in efficiency at 700mA which is a large improvement in grams/W. In a large grow that is a lot less heat to deal with. Since the drivers are so cheap you could always swap them in an out as needed.
 

Bueno Time

Well-Known Member
700ma seems fine to me. I like the brightness level they hit at that current

all ol my leds are just a inch or so apart...but my heatsink is beefy and the fans are fast. So I'd spread them a bit more otherwise..

wish I could give more exact numbers, maybe supra or someone will chime in. Still learning myself..
Or for more satisfying tweaking get an lpf-60d from MeanWell for $33 odd bucks - and use it at a range of different outputs. :success: lol
CXA3070 3000K Z2 bin:
43% @ 700mA
40.7% @ 900mA
39.42% @ 1050mA
36.6% @ 1400mA

Nothing wrong with running at 1400mA, you get almost twice as many photons for your dollar, but on the other hand you get 17.5% increase in efficiency at 700mA which is a large improvement in grams/W. In a large grow that is a lot less heat to deal with. Since the drivers are so cheap you could always swap them in an out as needed.
Thank you for the replies guys!

Im about to order a driver or two and try to find a place with 3070 3000k z2 that is in stock.

Would one of these work?

http://www.fasttech.com/products/1612/10004218/1320600


Its rated 50w 1600mA. If it would, Im going to grab one of these and one of the 30w version so I can play with different watt/amperage drivers.

edit: found the answer while reading a different thread.

I tested the 1.6A fasttech cheapo driver. Actual current was 1.3A and is regulated throughout its vF range which is 19-36vF. Efficiency was 90-91.5%. If you go under 19vf it will flash, if you go over 36.5Vf, the current drops off to nothing very quickly.

Unfortunately these are not guaranteed to work with the CXA3050, CXA3070 or Vero 29 but it would work for the Vero18. I was able to get it to work on my CXA3070 at 36.57vF, but if there is any variation in the vF of the COB or in the driver itself the current could be drastically reduced.
 

Positivity

Well-Known Member
Bueno>> I was answering redcarpets question on deep reds at 700ma. Sorry..should have been clearer.

I'll let supra answer your driver questions, he has much more experience than me. Good luck with your DIY project..it is very rewarding and worthwhile.
 

PeterFox

New Member
Gentleman,

after spending 25+ hours reading on LEDs in this forum I have some questions in choosing an appropriate LED setup. But first let me thank you for your time and efforts in researching and providing all the informations.
Specs and setup so far: Starting my first indoor grow with one old 70 watt 830 CDM-TD powerball-in-a-crappy-cheap-floodlight, I have plans for upgrading my lightning before buying an appropriately sized flightcase for permanent <100 Watt stealth and quiet microgrowing. Plant height including distance from lamp but without pot shall be somewhere in the range of 1-2 foot, the smaller the better.
The CDM-T is specified with 6500 lumen when new, so as the lamp is second-hand maybe 620 , resulting in probably no more than 5000 lm at the 10 by 10 inches sized canopy when the lightsource is within a distance of 3 inches above the latter. Venting is done through a 160 cbm/h carbon filter with a Papst type 4184 NXH 11W 12-25V-DC starting reliably from 4.5 V on (->no PWM fan). Quiet and powerful at 12 V. BTW, SupraSPL, thanks for linking the efficent 5$ 12V 2A power supply with adjustable voltage, ordered. Air circulation is provided by one 2.5 Watt Crest Mini USB Powered Desktop Cooling Fan SY-ACC65055, works nicely.

Aiming at 2 plants in flowering (perpetual, i.e. one ~4 weeks younger than the other) with each one not exceeding 10x10 sq inch horizontal size, I thought on two CXA3070-0000-000N00Z230F-ND powered with either 700 or 900/1050 mA. I already ordered three 9.99 $ pure copper CPU heatsinks for passive cooling (each 2x3x3.5 inches, 1.2 kg weight:hump:, estimated surface area ~5050 sq cm, but small fin distance) http://www.primelec.com/ibm-xseries-passive-copper-networking-accessories-p8842071.


So coming to the questions that arised:
(1) Is there any better bin or spectra suggestion for a pure flowering panel than CXA3070-0000-000N00Z230F-ND or are different spectra/bins for the older and younger lady advised?
(2) Any better option than CXA3070?
(3) One COB powered at 900-1050 mA shall be able to replace the 70 W cdm-TD that seems to supply adequate light. When kindly gazing in your crystal balls, will I be able to supply sufficent (semi-)passive cooling when running with 900 or 1050 mA per COB? Which driver when aiming at the lower end, around 900 mA?
(4) Is it (ben)efficient to add 1-4 red or blue or XML stars to a CXA !in series! on the heat sink to optimize the spectra and/or slightly increase wattage and efficency. As of my concerns under (3), a ~50V 700 mA power supply would power the cob with a 5-9% increased efficency while the LED stars could compensate the missing wattage. Downside is that I have no glue which parts to source and will not have the time to dig deep enough into the topic. Have to build a light, now:hump::
(5) A pure bonsai mother/vegging/cloning light is urgently needed. What is your advise, Cree XM-L2 U2-4C (How many?) and which red/blue for good spreading and the option to change the chain length depending on the amount of plants that need to be illuminated. Or simply a CXA3070-0000-000N00Z450F-ND or CXA3070-0000-000N00Z240F-ND? Will a 350 mA power supply provide sufficent energie to provide an adequately trained (scrog or better, twice tipped) small plant every 4 weeks, what wattage to aim at?

Cheers
 
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