Advice on COB - 4x4 grow

hi, growers!

1st time posting and 1st time grower here trying to get some advice on lightning.
Still a little bit confused on diy COB fixtures and especially insecure about what's "really" necessary to grow some plants (maybe 3-4 for that space?) and, yeah, I've read some good amount about it. But I also feel, regardless from reading, that I'll get more confident with some straight answers.

My grow will be whole diy. The initial idea is to build a closet grow (something like) with wood as the structure, 4x4 (1,20m x 1,20m approx).
I plan to grow 3-4 plants in that space (too little or too much?).

As for lightning... here comes most of the doubts.
I don't have that much money, that's why the idea of diy'ing everything (things are expensive here in my country).
With that in mind and trying to have a decent crop...
what would guys suggest for COB and drivers?

I initially thought on 4x Citizen CLU048-1212 GEN 6 90 CRI 2700K and 2x Citizen CLU048-1212 GEN 6 80 CRI 4000K.
Would that be decent? If so, what would be a good driver to pair with? I've read and found some calculator for that, but would like to check with you all anyway.


my most sincere thanks.

I'd go with strips or boards these days.

What price on the clu48s these days?

I checked the data sheet on my old clu058s other day and prices and they were over £60 a peice then you've got pin heatsinks, mounting ect.

For a 4x4 I'd be looking at 560-600w
Can't remember the specs for cku048s but thinking you'd want 9 of them ?

Correct me if I'm wrong

4 plants I perfect btw for your space.

coreywebster said:

What price on the clu48s these days?

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the website I'm looking it seems $8 COB and $18 passive heatsink.

coreywebster said:

I'd go with strips or boards these days.

Click to expand...

by that, what do you mean? quantum boards? if so, for that space (4x4) which would you recommend?


and still about the COB's... if I went with them, how many would be a good amount for that space?

grower.johndoe said:

the website I'm looking it seems $8 COB and $18 passive heatsink.


by that, what do you mean? quantum boards? if so, for that space (4x4) which would you recommend?


and still about the COB's... if I went with them, how many would be a good amount for that space?

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Yeah I just googled to check prices.

5x clu048 £40

Not bad.

I'd have to look at data sheet again to see wattages ect.

Generally people aim for high efficiency, think you could go with 6 but 9 would be a better build.
It's balancing cost vs efficiency .

And yeah I was referring to Samsung boards or bridgelux strips .

Don't get me wrong cobs are still good and 90cri is lush

coreywebster said:

Generally people aim for high efficiency, think you could go with 6 but 9 would be a better build.
It's balancing cost vs efficiency .

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Thanks. I'll aim for that amount or close by, if I get to choose COB's.

coreywebster said:

And yeah I was referring to Samsung boards or bridgelux strips

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Which would be a good QB for a 4x4?

Honestly, if the prices are similar and the efficacy of QB's and COB's are also similar (are they?), I would choose QB's due to the fact that they're already assembled.

grower.johndoe said:

Thanks. I'll aim for that amount or close by, if I get to choose COB's.


Which would be a good QB for a 4x4?

Honestly, if the prices are similar and the efficacy of QB's and COB's are also similar (are they?), I would choose QB's due to the fact that they're already assembled.

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You'd want 4 boards in a 4x4 .
Either 2x meanwell 240 drivers or 2x 320 drivers

Honestly the 240s are enough .

Lemme torment you a little longer @coreywebster ... and sorry about that.

Let's say I'm choosing to run 10xCLU048-1212 36 V at 1,4 A aiming more or less 500 W (guessing... that's a good amount for a 4x4?).
For that build, which driver would be the best match?

And would you recommend a heatsink for each COB or a big aluminum heatsink and mount them all in?

grower.johndoe said:

As for lightning... here comes most of the doubts.
I don't have that much money, that's why the idea of diy'ing everything (things are expensive here in my country).


my most sincere thanks.

Click to expand...

You could also try The Best Deals Thread there have been some really good deals with coupons/codes etc...

MedicinalMyA$$ said:

You could also try The Best Deals Thread there have been some really good deals with coupons/codes etc...

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Haven't seen that thread yet. Will take a look! Thanks, fellow!

grower.johndoe said:

Lemme torment you a little longer @coreywebster ... and sorry about that.

Let's say I'm choosing to run 10xCLU048-1212 36 V at 1,4 A aiming more or less 500 W (guessing... that's a good amount for a 4x4?).
For that build, which driver would be the best match?

And would you recommend a heatsink for each COB or a big aluminum heatsink and mount them all in?

Click to expand...

Sorry, I was in the middle of a poker game last night.

I'll have to get my thinking cap on regarding matching the best drivers, been a while since I've thought about this stuff.

For cobs you definitely want a pin heat sink per cob.

In the meantime try looking on YouTube for growmau5 's video series , if they are still available.

Or use the search bar here and look through some of @CobKits threads as he used to write a lot of useful info. Don't think I've seen him for a long time though

Here's the first part of a 6 part series that's helped most of us that built cob fixtures back in the day.

I recommend watching all parts but specifically the one about matching drivers

1 cob per sq ft. Been a long time lol


Here's other options - led strips. 2ft or 4ft strips

coreywebster said:

Sorry, I was in the middle of a poker game last night.

I'll have to get my thinking cap on regarding matching the best drivers, been a while since I've thought about this stuff.

For cobs you definitely want a pin heat sink per cob.

In the meantime try looking on YouTube for growmau5 's video series , if they are still available.

Or use the search bar here and look through some of @CobKits threads as he used to write a lot of useful info. Don't think I've seen him for a long time though

Click to expand...

im still around, not on the board all that much

ill always recommend 9 luminus cxm22 on pinfins for a 4x4. ~70W each on a 600h-54b driver

the clu048-1212s are cheaper but you need more and thats more heatsinks. id go 12 for that space and still not as efficient as the luminus

also 3500k across the board would give you best spectum and more uniform than mixing colors

My only gripe is about the Meanwell drivers... I installed at least 30 drivers, and had to replace at least 6 under warranty due to failure. Can't say if they were all manufactured within the same time period or not...

that sounds like a high failure rate from my experience

any other factors? is the power pretty clean, were they installed in a cool-ish space, etc?

CobKits said:

ill always recommend 9 luminus cxm22 on pinfins for a 4x4. ~70W each on a 600h-54b driver

the clu048-1212s are cheaper but you need more and thats more heatsinks. id go 12 for that space and still not as efficient as the luminus

also 3500k across the board would give you best spectum and more uniform than mixing colors

Click to expand...

that seemed like an interesting build. I'm already taking a look at that build price and might go for it.

is there any diy video of that 9x CXM22 frame/assemble for a 4x4?
asking because I might be slightly insecure about the spacing between cobs and the best frame/cobs distribution to cover the 4x4.

and honestly... deep thanks for all of you guys. wasn't sure about getting some answers here and you already helped a lot.

Cobs should be spaced at 12" on center, three rows of three..

How about a recommendation for a 3x3x5 tent as I have always been interested in a cob build???