Tweak my DIY COB set up

BDGrows

BDGrows

Well-Known Member
So my grow area is 5sq ft (36"x20"), and I am wanting to run my cobs at the highest efficiency (in order to produce minimal heat). So the set up I was thinking of would 8 cobs,

4x Citizen CLU048-1818 90CRI 3000k

4x Citizen CLU048-1818 80CRI 3500k

2x 30” of 5.886 w/ a 140mm fan for active cooling

And a HLG-185H-C500A to power all 8 of the cobs.

I was planning on having 2 separate lights and placing them side by side in my tent in order to get the most effective spread. I was going to alternate the 3500k and the 3000k to have an optimal distribution of light. Is there anything else I should consider or what could be done to make this light better? Thanks for all the help!


- BD
 
berten-ernie420

berten-ernie420

Well-Known Member
BDGrows said:
So my grow area is 5sq ft (36"x20"), and I am wanting to run my cobs at the highest efficiency (in order to produce minimal heat). So the set up I was thinking of would 8 cobs,

4x Citizen CLU048-1818 90CRI 3000k

4x Citizen CLU048-1818 80CRI 3500k

2x 30” of 5.886 w/ a 140mm fan for active cooling

And a HLG-185H-C500A to power all 8 of the cobs.

I was planning on having 2 separate lights and placing them side by side in my tent in order to get the most effective spread. I was going to alternate the 3500k and the 3000k to have an optimal distribution of light. Is there anything else I should consider or what could be done to make this light better? Thanks for all the help!


- BD
Click to expand...
8 cobs for 5 sq ft of grow area? Seems a bit overkill imo. I thought 1 cob per sq ft was optimal. Cost is going to go up with the more cobs u use as well as cost to run. For 5 sq ft i would just run maybe 6 cobs, on the hlg320. But thats just me. Let me ask u this, why so set on 8 for 5 sq ft? And why run at such low current?
 
BDGrows

BDGrows

Well-Known Member
I think my math was off. I've also changed the chips to 3500k Cree CXB3590's. So if I were to run 6 of the CXB's on a hlg 320h-c1400 it would be enough for 5 sq ft? If I were to run them at .7A, it would be an optimal 30w/sq ft for veg, and at 1.4A, 60w/sq ft for flower; right?
 
Abiqua

Abiqua

Well-Known Member
wattage doesnt double with increased amperage unless the efficiencies are way off...30w at 50% per sq ft...thats around 15 PARw x 4.65 ...good for around 70ppf rough average of 5 sq. ft [36x20]= 350 ppf / 750 ish ppfd

60 watts of similar efficiency will double the above numbers....:peace:
 
BDGrows

BDGrows

Well-Known Member
Abiqua said:
wattage doesnt double with increased amperage unless the efficiencies are way off...30w at 50% per sq ft...thats around 15 PARw x 4.65 ...good for around 70ppf rough average of 5 sq. ft [36x20]= 350 ppf / 750 ish ppfd

60 watts of similar efficiency will double the above numbers....:peace:
Click to expand...
Doesn't a higher PAR value mean deeper canopy penetration which is a good thing right?
 
BDGrows

BDGrows

Well-Known Member
Abiqua said:
It means higher light density which is penetration. penetration is a misnomer of sorts.
Click to expand...
So at what point is too much saturation? The issue I had with my last grow was fluffy buds and I am trying to correct that. I am switching from a 400hps which was producing a ton of heat (which is why I think they were fluffy). So would I produce less heat if I ran the cobs at a lower wattage but still have as effective light density as I would with a 6 cob set up?
 
Abiqua

Abiqua

Well-Known Member
BDGrows said:
So at what point is too much saturation? [ The issue I had with my last grow was fluffy buds and I am trying to correct that. I am switching from a 400hps which was producing a ton of heat (which is why I think they were fluffy). So would I produce less heat if I ran the cobs at a lower wattage but still have as effective light density as I would with a 6 cob set up?
Click to expand...

Its kinda a loaded question....how many runs did you before with the 400w and same soil water nutes and in exacting amounts....etc etc...1, 2? too many variables....

I am more in the wait and see, sit back and analyze strain by strain then condition by condition.....more data not better analysis

I have had great yields in the sub <600 ppfd range with diffuse spreading of light....

but the popular theory ranges from 1000ppfd to 1500 absolute with CO2 and ideal conditions [when is a grow environment ever full ideal? ....never....... it kinda bounces back and forth, thats is why these questions aren't so straight forward to be answered.....]
 
Moflow

Moflow

Well-Known Member
I think that 320 watts of cobs v 400 watts of HPS in your space will produce far better for you with less heat to deal with.
A better spread of light to the edges , no hotspot in center, more direct light to the plants as opposed to reflected light and no ir heat.
I am using 600 watts of cobs in lieu of 660 watts hps at moment in 30" x 40" ish area and my temps are 71-72f lights on as it's winter time.
Not optimum temps I know but plants look OK and seem as if they'll be ready at 56 days so a bit faster than under HPS.
It's going to be another couple of runs for me to get dialled into the cobs but no regrets so far.
 
berten-ernie420

berten-ernie420

Well-Known Member
Heres a lil something i smashed together. Dont mind the little monster underneath it, shes a cutting from my last plant im trying to nurse back to health. But its an idea. I went with the "H" style instead of the bar because im going to build one more pretty much identical to this one and put it side by side.
 

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