Cxm22 questions

CobKits

CobKits

Well-Known Member
oilfield bud said:
Ok so is one of the reasons they are less efficient because they create more heat when ran harder?
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yes thats fundamental with all LEDs, its all about heat dissipation. even with super cooled heatsinks, there is still thermal resistance that must be overcome between the diode junction and the case, and then the case and the heatsink. You can play around with the simulators on the manufacturers site, and see the effect of junction temp (Tj) and case temp (Tc)

With equal heat removal from the heatsink, more current, is always going to result in a drop of efficacy because its about MOVING that waste heat to the heatsink
 
oilfield bud

oilfield bud

Well-Known Member
Man I got a 2 ton ac in a 9x12 room and was told I had to run a cob grow warmer then my hps grows. And I'm trying to max my yeild from that space. I was running 3 to 4 1000w as cool as possible and it was working pretty well but my buddy who is running Les watts with cobs was killing it. So that's why I'm trying to figure out not really what's most efficient. But how I can yield the most in my garden you know.
 
Go go n chill

Go go n chill

Well-Known Member
oilfield bud said:
Man I got a 2 ton ac in a 9x12 room and was told I had to run a cob grow warmer then my hps grows. And I'm trying to max my yeild from that space. I was running 3 to 4 1000w as cool as possible and it was working pretty well but my buddy who is running Les watts with cobs was killing it. So that's why I'm trying to figure out not really what's most efficient. But how I can yield the most in my garden you know.
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24 cobs would be the number for me at 3500 ran between 70-80 watts each. but listen to Cobby
 
Renfro

Renfro

Well-Known Member
I would plan my lighting based on a wattage per square foot of canopy. So if you want to light a whole 9x12 area thats 108 sqft. 35 - 40 watts per sqft. 3780 - 4320 watts is what you want to be putting out (total DC wattage from the drivers to cobs). Now spread that evenly and you have your room lit. If you wanna build modules that have a driver and some cobs with optimized spacing then you can hang them wherever you need and set heights / dim individually. I even have some 55w autocobs running around that I hang to boost the light in areas that don't get enough direct light. The autocob is just a cob/heatsink with a dedicated driver, just dangle them where you need them. Not the cheapest way to do it but it just shows that you don't have to build a big light, you can use several smaller ones. Whatever is easier for you to do to get your light where you need it.

Go go n chill said:
24 cobs would be the number for me at 3500 ran between 70-80 watts each. but listen to Cobby
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24 cobs at 80 watts is 1920 watts, IMO only enough for half of the area he has, 54 of 108

If he ran 4000 watts (37 watts per sqft):

Cob Watts - # of cobs
60 - 66 or 67
70 - 57
80 - 50
 
oilfield bud

oilfield bud

Well-Known Member
Lol ya 4000w would be killer in that room. But my budget won't allow 4000w to start with. And I need room to get in there lol. But I can swing 2400w with 32 cobs over a 8x8 area running 75w a cob. That would give me 37w a square foot. After the first or second run I can add more cobs and more wattage
 
Renfro

Renfro

Well-Known Member
The lights I am building consist of 72 CXM-22 gen 4's running at a max of 60 watts each. Total watts 4320

I am hanging them over "rows" that have trellis rigs in a 4 x 8' area but the plants do get wider and I rely on my existing lights to hit a little more area. So 96 sqft in the trellis rigs puts me at 45 watts per sqft (high) but I am hanging them high enough and spreading the cobs such as to cover a little more than just 4x8.

All in all it's always a game of figuring out how to best place the light sources so as to provide adequate and even coverage of your canopy. The more powerful the sources the farther apart they will be.

oilfield bud said:
Lol ya 4000w would be killer in that room. But my budget won't allow 4000w to start with. And I need room to get in there lol. But I can swing 2400w with 32 cobs over a 8x8 area running 75w a cob. That would give me 37w a square foot. After the first or second run I can add more cobs and more wattage
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Good plan, cover what you can with the wattage you can afford, not spreading it too thin. Later add more lights. You never know, maybe they will have a gen 5 chip when you buy more lol. I have gen 3 in my tent light and gen 4 in my current build.
 
Go go n chill

Go go n chill

Well-Known Member
Renfro said:
I would plan my lighting based on a wattage per square foot of canopy. So if you want to light a whole 9x12 area thats 108 sqft. 35 - 40 watts per sqft. 3780 - 4320 watts is what you want to be putting out (total DC wattage from the drivers to cobs). Now spread that evenly and you have your room lit. If you wanna build modules that have a driver and some cobs with optimized spacing then you can hang them wherever you need and set heights / dim individually. I even have some 55w autocobs running around that I hang to boost the light in areas that don't get enough direct light. The autocob is just a cob/heatsink with a dedicated driver, just dangle them where you need them. Not the cheapest way to do it but it just shows that you don't have to build a big light, you can use several smaller ones. Whatever is easier for you to do to get your light where you need it.


24 cobs at 80 watts is 1920 watts, IMO only enough for half of the area he has, 54 of 108

If he ran 4000 watts (37 watts per sqft):

Cob Watts - # of cobs
60 - 66 or 67
70 - 57
80 - 50
Click to expand...
Well I run 4 at 73watts each in a 2x3 and it kicks ass. I just ramped my grow up to match his room size. I consistently get a pound harvest dried cured.
 
Renfro

Renfro

Well-Known Member
So have you decided what power level you want to crank them at? Given what cobby says there is a sweet spot but IMO unless you get really far away from that by cranking it to the max the pros (more light for less money) will still outweigh the cons (little less efficient, little more heat). If I was on a limited budget I would probably be driving mine harder like @Go go n chill is doing just so I could cover more space with less cobs, spreading them out a little more. I would have to keep the plants just a little shorter since the light needs to be a little farther away.
 
Go go n chill

Go go n chill

Well-Known Member
Renfro said:
I would plan my lighting based on a wattage per square foot of canopy. So if you want to light a whole 9x12 area thats 108 sqft. 35 - 40 watts per sqft. 3780 - 4320 watts is what you want to be putting out (total DC wattage from the drivers to cobs). Now spread that evenly and you have your room lit. If you wanna build modules that have a driver and some cobs with optimized spacing then you can hang them wherever you need and set heights / dim individually. I even have some 55w autocobs running around that I hang to boost the light in areas that don't get enough direct light. The autocob is just a cob/heatsink with a dedicated driver, just dangle them where you need them. Not the cheapest way to do it but it just shows that you don't have to build a big light, you can use several smaller ones. Whatever is easier for you to do to get your light where you need it.


24 cobs at 80 watts is 1920 watts, IMO only enough for half of the area he has, 54 of 108

If he ran 4000 watts (37 watts per sqft):

Cob Watts - # of cobs
60 - 66 or 67
70 - 57
80 - 50
Click to expand...
I’m stoned!!! My bad, my math was retarded
 
Renfro

Renfro

Well-Known Member
Driving them at 73 watts, to cover all 108 sqft he would want 55 cobs. So if he buys part now (say 30 - 33 for the 8 x 8) and the rest later he's good to go.
 
oilfield bud

oilfield bud

Well-Known Member
Man coming from hps I've never turned a light down. I've started seeds under 1000w but just started them super high and brought them down as the plant matured. I'll probably be cranking the cobs at the full 75w each until I figure the hight out.
 
oilfield bud

oilfield bud

Well-Known Member
If I can pull your numbers I'll be stoked. I'll be working my way into a much larger space and then I'll definitely be more concerned about efficiency


Go go n chill said:
Well I run 4 at 73watts each in a 2x3 and it kicks ass. I just ramped my grow up to match his room size. I consistently get a pound harvest dried cured.
Click to expand...
 
oilfield bud

oilfield bud

Well-Known Member
Ya thank y'all both for all yalls input. I'll be placing my order threw coby sometime this month so I'll make sure to start a jernal. I'm starting over from scratch bc I've taken about a year off so I'll have to pop some seeds and do a lil pheno hunting
 
Renfro

Renfro

Well-Known Member
I have a batch of candy rain beans in my tent. doing a little pheno hunt myself. like a box of chocolates, never know what you are gonna get! kinda fun since I mostly mess with breeders cuts where it's a known quantity. It's fun to see the different pheno types express themselves. Often the most difficult part is picking the winner. Sometimes you get a lot of genetic variation and thats fun for pheno hunting. Find that rare rare... :hump:
 
oilfield bud

oilfield bud

Well-Known Member
Ya one of the reasons I stopped for a while was because I eas having trouble getting seeds. Lol can't get clones in Texas. Haha but I'm about to give a couple of green points strains a try. They will be in first before I can make my seedsmen order.
 
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