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swedsteven said:

To reach the best efficacy ppfd/w
49cob on a 4' by 4' metal plate
no heat sink no frame
490 watts dimmeble to 245 watts
Ill be able to keep the cob at about 4 inch to 6 inch and get the best coverage and high umol at the canopy with low wattage just to build the best !
View attachment 4115589

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This might tickle your fancy. I don't know where I got these PPFD charts from exactly, but it's taken from a 20x CXB3590 setup over a 4x4' area, at 511w total

Here's 12" distance



24" distance



Pretty damn uniform, and the efficacy is decent. If he wired it all so each cob was at 350mah though, he'd go from 156 lumen/w to 177 lumen/w. Or maybe he mislabed it with 700mah, i dunno I need a coffee lol.

Strips blow that out of the water in terms of uniformity though, and mine run at the samne exact 156 lumen/w after driver losses and all that shit. And it didnt cost me $2000 lol.

skoomd said:

Strips blow that out of the water in terms of uniformity though,

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can you link a PAR map so we can see the difference?

skoomd said:

And it didnt cost me $2000 lol.

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nor would a COB rig in modern times

CobKits said:

can you link a PAR map so we can see the difference?


nor would a COB rig in modern times

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Ill try to find one and edit this post, but im just basing that off of the lux readings im getting under my newest strip build. I'm getting 48,000 to 53,000 lux pretty much everywhere at 12" away. Maybe I can make a PPFD chart using my lux meter? I know it won't be 100% accurate, but there is a huge lack of strip build PPFD charts out there.....

it dosent matter if its ppfd or lux. what matters more is getting a nice uniformly spaced grid of 100 points or more (the one you linked above was 121 points). note its pretty damn uniform except in the corners so be prepared to measure 4" from the wall. youd really need an empty tent and crawl inside and measure.

that data is really useful though. in the cob case id yank one cob from the center and crank it up to 1050 ma and have a nearly perfectly uniform 700-800 ppfd

CobKits said:

it dosent matter if its ppfd or lux. what matters more is getting a nice uniformly spaced grid of 100 points or more (the one you linked above was 121 points)

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Hmm, I might embark on doing this a bit later today then. It would take a while to plot out that many points, but it shows uniformity off much better than the normal PPFD charts using like 16-32 points.

What software do I use to make the plot?

you can do that in excel

make the cells square
use conditional formatting
"if value is between 600 and 700, make cell this color, if between 700 and 800 make it that color", etc. looks like they went a little more detailed than that but once you set it up you can save it and use it again and again

im not sure of the formula for uniformity, probably some basic statistical calculation like standard deviation, etc.

skoomd said:

but it shows uniformity off much better than the normal PPFD charts using like 16-32 points.

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by definition more data points is going to give you a more accurate number

if you felt like crunching numbers you could average those cells above into blocks of 4 or 9 and you'd see that the uniformity probably goes up

in any case, if uniformity is your measure, number of datapoints is kind of critical, because thats the nature of your measurement

The concept is good, the execution however..... do you realize how much weight you'll have hanging?? I'd put safety chains on it, would be sad to crush a grow! Might be better to use a .250" plate of Aluminum. And people get too hung up on this whole uniform coverage thing. Its just not that critical. I grew these with one, 4 COB fixture and 2 other cobs as side light running at 270 watts. . In a reflective environment, and certainly my plants were quite happy. Realistically, a 16 cob light will do what you need just fine.

swedsteven said:

To reach the best efficacy ppfd/w
49cob on a 4' by 4' metal plate
no heat sink no frame
490 watts dimmeble to 245 watts
Ill be able to keep the cob at about 4 inch to 6 inch and get the best coverage and high umol at the canopy with low wattage just to build the best !
View attachment 4115589

Click to expand...

pop22 said:

The concept is good, the execution however..... do you realize how much weight you'll have hanging?? I'd put safety chains on it, would be sad to crush a grow! Might be better to use a .250" plate of Aluminum. And people get too hung up on this whole uniform coverage thing. Its just not that critical. I grew these with one, 4 COB fixture and 2 other cobs as side light running at 270 watts. . In a reflective environment, and certainly my plants were quite happy. Realistically, a 16 cob light will do what you need just fine.


View attachment 4116154

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Yeah, fuck, 49 cobs on a frame with heatsinks, drivers, and all is gonna weigh close to 100lbs no problem.

The 1/8" rope ratchets with metal gears are rated for like 100lbs each, and the 1/4" like 200lbs each, but im not sure how much I would trust those numbers. Chains would be a good idea.

i put 9 cobs on a frame in a 3x3 tent and its stuffed with uniform light. and the heatsinks dont barely even get warm at 25-30W/cob

I had a rope ratchet fail and dropped a 22 pound light on some plants just starting to flower plants......... crushed them all.........

skoomd said:

Yeah, fuck, 49 cobs on a frame with heatsinks, drivers, and all is gonna weigh close to 100lbs no problem.

The 1/8" rope ratchets with metal gears are rated for like 100lbs each, and the 1/4" like 200lbs each, but im not sure how much I would trust those numbers. Chains would be a good idea.

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:: pours one out ::

I already have the 16 x 1212 setup running at 50 watts each cover 5' × 4.5'

I will love to see if this could work at 320 watts those 44 × 1212 wont be hot at all so the aluminium board dond need to be thick and the way i want to set it up ill be able to drop it lower without hot spot . And a good spread . High ppfd
It worth it still under 1000 $ lol

I feel like spending again those led are making me ...

shoot for 1/8" thick min heatsink even at low power on cobs

im just gonna drop these off over here..........
im a firm believer in the citi 1212s for the price. i dont see much of a difference between my 1212s and cxm22's. ideally i would have run less cxms and pushed them harder but i was new to LED and went the overkill route. live and learn. these got a bit burned. learning a new system with 12 different strains/phenotypes is a bitch. either way it was a success and the next round will be even better. if you arent striving to improve every round you're in the wrong game! im gonna simplify and do rockwool with floraflex drippers and one strain per reservoir. more work but less issues hopefully

follow me on IG if that's your thing. Desert.Hydro
quantum style builds coming soon!

so i have decided that i want to get 3 cxm22 gen 3 400k and 3 cxm22 gen 3 3000k but would like them to be on seperate drivers and be dimmable. would like to run the cobs at around 50w each and to have room to run them lower and higher. what driver would work. thanks

you could do it with (2) hlg-120-48A, but the hlg-185-48A is just a few more bucks and gives you the option of maxing out those chips later on

every driver i sell is dimmable

swedsteven said:

And will it be logical to do that or pratical

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Logical? Maybe. Practical? Not really, considering the cost of 49 citi 1212 gen 6 cobs is in excess of $700. Then you got the cost of mounting, wiring and power - nearly $1k for a 200W light is not very practical.

CobKits said:

you could do it with (2) hlg-120-48A, but the hlg-185-48A is just a few more bucks and gives you the option of maxing out those chips later on

every driver i sell is dimmable

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would those drivers be able to run the cob at 50V and 1.05A the data sheet says 1.95-3.9A?