What cobs are good cobs?

CobKits said:

clu048 drilling works for luminus. id go with the cxm22

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Ok I'll check them out, thanks! Also what would be the difference in the watts/ma. Say I want to push a Vero or clu or cxm at 80 to 95w would it be better for 1400ma or 2100ma and why? Still trying to learn and have read a ton of your reply and comments on these forums and know your the one to ask if it relates to led cobs!

Depends on the forward voltage of the COB.
A 36v COB(? parallel strings with 12 diodes in series) like a CXB would be ~50w at 1,4A and ~75w at 2,1A.
A CXM22 is a 50v COB(unknown number of parallel strings with 18 diodes), at 1,4A it would be ~70w and with 2,1A it would be ~107w.
To get 85w from Luminus CXM22 you need ~1,7A per COB.
You could use a HLG-320H-48A to power 4pcs CXM22 in parallel. Each COB would get 1675-1750mA and the whole lamp would have up to 350w. That's ~38-39w per ft² and almost perfect intensity for indoor growing. And don't worry about parallel wiring its completely fine with HLG CV/CC drivers. These drivers have build-in poti's for voltage regulation(left one) and dimming(right) you can dimm the light within 50 and 106%/driver maximum.

Each COB or LED has its own forward voltage. For white and blue single diodes it's for example 2,7-3,5v, for red and deepred diodes its 2,1-2,6v and 2,5-3,0v.
COB's have lots of diodes in a series-parallel circuit. The number of diodes in series determines the voltage a COB need. COB's like CXB's have 12 diodes in series and need ~34-38v depending on the current running thru the COB. With high 2,1mA it's probably 37v at only 1050mA it's ~35v.
COB's with 18 diodes like the CXM22 or Vero29b need ~48-52v.
The current running thru a COB determines his brightness. The more current the brighter the COB. But you will loose some effiency compared to more low driven COB's. When you get 160lm/w from a CXM22 at 2,1A(107w) you would get around 17,120lm total. At 1050mA you would get ~51,5w but 180lm/w, thats 9.270lm but you need two COB's to get better brightness.(18.540lm from only 103w). The more COB's you use the better the efficiency of the fixture..

Randomblame said:

When you get 160lm/w from a CXM22 at 2,1A(107w) you would get around 17,120lm total. At 1050mA you would get ~51,5w but 180lm/w, thats 9.270lm but you need two COB's to get better brightness.(18.540lm from only 103w). The more COB's you use the better the efficiency of the fixture..

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CXM22 are not that efficient, Randomblame. I think they're in 140-160 lm/W range at 1050mA and 1400mA. Same as Citi 1212.
CXM32 is another story.

Greenman218 said:

Say I want to push a Vero or clu or cxm at 80 to 95w would it be better for 1400ma or 2100ma and why?

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depends on the voltage. all the chips 'model numbers' you list actually represent multiple products with different specs. dont get hung up on current, rather overall wattage (voltage x current)

KonopCh said:

CXM22 are not that efficient, Randomblame. I think they're in 140-160 lm/W range at 1050mA and 1400mA. Same as Citi 1212.
CXM32 is another story.

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cxm22 are substantially more efficient than 1212s. they are just above 1818s/vero C/vero B below 75W. 1818 and veroC start to pull ahead above 100W

Best CXM22 3000K 80 CRI is 153 lm/w:
CXM-22-30-80-54-AC30-F4-3 22 3000K 80 8384 52.2 54.8 153 45.7

Citi 1212 gen 5 3000K 80 CRI is 155 lm/W. Gen 6 is even more efficient.

Both under Tc 55°C.

KonopCh said:

CXM22 are not that efficient, Randomblame. I think they're in 140-160 lm/W range at 1050mA and 1400mA. Same as Citi 1212.
CXM32 is another story.

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Yea, it was more thought as an example to show how it works. I've not used them till now because they are too expensive here(incl. VAT/custom fees and shipping). But I believe cobkits when he says they are underestimated in the datasheets and he has measured them brighter in his own sphere. And especially the 1212 from Citizen seems to be overestimated at lower currents.
For him it does not matter which COB one buy because he determines the profit margin of all COB's equally. Below 75w it's hard to beat them with the same money.
Cobby has a few threads with lots of performance charts where you can see them compared to other COB's.

Lol you can't compare the lm/w off datasheet and call that an acurate comparison.

Cxm22 @1400ma , you would have to drive a 1212 at 2100ma to match it. You get 2.1 vs 1.7 umol/j. 1212 aren't even 2 umol/J at 1400ma.

KonopCh said:

Best CXM22 3000K 80 CRI is 153 lm/w:
CXM-22-30-80-54-AC30-F4-3 22 3000K 80 8384 52.2 54.8 153 45.7

Citi 1212 gen 5 3000K 80 CRI is 155 lm/W. Gen 6 is even more efficient.

Both under Tc 55°C.

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the lack of parity between different manufacturer's datasheets and actual chips in service has been demonstrated time and time again.

i would only ever use datasheets of a given single mfr to compare their different offerings. mfr to mfr always seems to be biased one way or another

diyled said:

Lol you can't compare the lm/w off datasheet and call that an acurate comparison.

Cxm22 @1400ma , you would have to drive a 1212 at 2100ma to match it. You get 2.1 vs 1.7 umol/j. 1212 aren't even 2 umol/J at 1400ma.

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Yea, one is 36V, other is 48V.
But you can compare lm/W, why not.

Btw, Citi 1212 is 2.17 umol/J at 1.4A under above conditions I mentioned. You can get 2x 1212 for the same price of CXM22, so better spread, efficiency, coverage...

I like them, 6x 1212 at 1050mA (220W, 155 lm/W) get me to 450g dry with only two autos. I guess I can get much more with new chips like 561C or 301B.

Theres an old saying, "U get what U pay for"

Im running a 400 watt Vero 29 V7 Color temp 3000 K from Timber,

All U could ask for in a light

KonopCh said:

Yea, one is 36V, other is 48V.
But you can compare lm/W, why not.

Btw, Citi 1212 is 2.17 umol/J at 1.4A under above conditions I mentioned. You can get 2x 1212 for the same price of CXM22, so better spread, efficiency, coverage...

I like them, 6x 1212 at 1050mA (220W, 155 lm/W) get me to 450g dry with only two autos. I guess I can get much more with new chips like 561C or 301B.

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It just doesnt work like that. compare them watt for watt. And system costs

That's a great result btw. It's not the light, it's the grower.

KonopCh said:

Btw, Citi 1212 is 2.17 umol/J at 1.4A

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where did you get that number from?

blowincherrypie said:

Nice.. but you need to get some more plants in there to increase your gpw! and thems some funky lookin leaves on the little ones lol

I just placed an order from Omega a couple days ago. Lookin forward to see what he put together. Ive wired up my last few cobs but his pricing wasnt that much more than if I pieced the shits together myself..

https://www.omegalight.net

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Man, which ones look funny? Not being a dik, just being proactive, if i missed something.

That is fire OG, it always grew funky leafs, lol..

I guess Im going to get flamed for saying i expect 2.5GPW off these 2 plants?

InTheValley said:

Man, which ones look funny? Not being a dik, just being proactive, if i missed something.

That is fire OG, it always grew funky leafs, lol..

I guess Im going to get flamed for saying i expect 2.5GPW off these 2 plants?

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gotcha. I thought they were throwing singles but looking closer it looks like theyre mostly the funny lookin OG 3

Bitches are growin fast. I just started watering 9 times a day, yesterday, so going to be interesting to see the speed they grow. These are in cocoloco. also, I wont be defoliating these. Trying realllllllly hard not to take a leaf off,lol.
these are 2 weeks from solo cup transplant, and running out of room. Chopping the fruited plants down in 2 days. Going thru last watering, to dry out, split stalk tonight, then 24 hours dark. So, in a couple days i can scrog them out. My scrog is 31in-37in, 152 openings for colas. I plan to fill them. going to flip in 2 weeks hopefully. I have to drag these chicks out everynight to keep in veg state, and they dont fit thru the doorway almost.

the flowering ones were 12/12 from seed, and the same strain i crossed the FireOG with, last grew out at 12/12 from seed, and the cola dry was 16g, just the top. so I crossed it with my FireOG that was short and squat, and is growing like the Father, which i wanted.

InTheValley said:

Man, which ones look funny? Not being a dik, just being proactive, if i missed something.

That is fire OG, it always grew funky leafs, lol..

I guess Im going to get flamed for saying i expect 2.5GPW off these 2 plants?

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So you're expecting 625 grams?

625g off them 2

Yeah man's, I know high expectations, but this strain is no joke. I dont have popcorn sht, every bud is bigger then a golf ball, and rock hard dense. add the fact, grown in 1 gallon pot, 12/12 from start, no root growth time, i was impressed. Ive been around thr green for 25 years and tons of sht, to never seen buds this big and dense. Im also being selective in what tops i let grow, the thicker the stem the better. SO cutting out alot of the thin branches and GMLin the tops of the fast climbers in the center. Every branch is micro supercropped. I dont bend them, i just slightly crush them to rush oxins to fix. Right now, i have about 140 tops. alot you cant see because I move the leafs around 5-6 times a day to adjust for light.