COB LED for veg?

S

Safehaven

Active Member
I have read numerous pages on DIY COB LED's. Nearly everything seems to only pertain to flowering. Would a COB setup be an ideal choice for the vegging process as well?

I have a 6.5' x 8' room, of which 4' x 8' is usable for veg. Do I need to illuminate the entire room, or just the usable space?

Which COB's/drivers in what configuration would be good for this space? I would prefer to passively cool.

I have T5's in a box ready to go up. But I like the idea of LED better if it is a viable option.
 
Stephenj37826

Stephenj37826

Well-Known Member
Safehaven said:
I have read numerous pages on DIY COB LED's. Nearly everything seems to only pertain to flowering. Would a COB setup be an ideal choice for the vegging process as well?

I have a 6.5' x 8' room, of which 4' x 8' is usable for veg. Do I need to illuminate the entire room, or just the usable space?

Which COB's/drivers in what configuration would be good for this space? I would prefer to passively cool.

I have T5's in a box ready to go up. But I like the idea of LED better if it is a viable option.
Click to expand...

5000k cree cobs would be excellent honestly.
 
AquariusPanta

AquariusPanta

Well-Known Member
4000~5000K is typically a great choice of temperature for seedling/vegging. You won't need as much light in veg as you would in flower and will only need to cover portions of the room where plant life will be present. If you go without optics, you can have some distance (x-axis) between lights and plants as most cobs are emitting at a standard 120 degree angle.

As for the configuration, that's totally your call. Vero is the more affordable cob between it and it's Cree counterparts (3070/3590) and is ideal for beginners as it can be screwed in without need of additional clamp/holder. Look into MeanWell drivers, as they seem to work the best for most of us here, with Chinese no name brands not being that much cheaper and in some cases being less reliable.
 
S

Safehaven

Active Member
Attached is the layout of the room I have already built. I have added a possible layout for LED lights. Each fixture contains two COBs set in 6" from the end, mounted on a 36"X5.88" heat sink. Fixtures are placed 24" on center.

Would a layout like this be overkill, underkill, or just right?

I'm thinking I will use Cree 3590's in the flower room. I will probably stick with Cree's for the veg room too. Is it better to use the 3590 in the veg room, or will the 3070's be sufficient?
 

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S

Safehaven

Active Member
4000K-5000K 3590's it is then. Still trying to figure out exactly how many I need for the space.

This is copied/pasted from another thread, and probably the route I will go for flowering.

@ 56.3%
(4) CXB3590 3500K CD 36V @ 1.4A (49W ea) $190
(1) HLG-185H-C1400 $65
196 dissipation W -> 85.7W heat ->
passive cooled heatsink 10284cm² -> 5.88" X 38" heatsink $72 (could split in 2 to improve uniformity/spread)
or
active cooled heatsink 3428cm² min -> 3.5"X36" heatsink (for spread) $45 +80mm fan +psu $10
(4) lenses $16
110.3 PAR W covering 6ft² = 824 PPFD
$311 = $3.07/PAR W passive cooled (great value point IMO, very efficient use of driver)
$326 = 2.96/PAR W active cooled

This is way overkill for vegging, correct? How many PAR W are needed per 6 sq. ft of veg?
 
J

JJ43

Well-Known Member
Safehaven said:
4000K-5000K 3590's it is then. Still trying to figure out exactly how many I need for the space.
Click to expand...
I think your layout is good for flowering. I think you can get away with fewer cobs for veg (6 maybe) for that 4x8 space.
All calculations and theoreticals aside, I find that veg doesn't require much light. I have a bunch of super-rooted (aeroponic) clones and teen plants (all now in soil) that go off of two 19w cree bulbs from Home Depot.
Currently I also have 9 cxb3590 3000k in a 5x5 tent in week 4 of flower. Killing it. It's like the forest of hope, love, and victory.
 
BOBBY_G

BOBBY_G

Well-Known Member
Safehaven said:
4000K-5000K 3590's it is then. Still trying to figure out exactly how many I need for the space.

This is copied/pasted from another thread, and probably the route I will go for flowering.

@ 56.3%
(4) CXB3590 3500K CD 36V @ 1.4A (49W ea) $190
(1) HLG-185H-C1400 $65
196 dissipation W -> 85.7W heat ->
passive cooled heatsink 10284cm² -> 5.88" X 38" heatsink $72 (could split in 2 to improve uniformity/spread)
or
active cooled heatsink 3428cm² min -> 3.5"X36" heatsink (for spread) $45 +80mm fan +psu $10
(4) lenses $16
110.3 PAR W covering 6ft² = 824 PPFD
$311 = $3.07/PAR W passive cooled (great value point IMO, very efficient use of driver)
$326 = 2.96/PAR W active cooled

This is way overkill for vegging, correct? How many PAR W are needed per 6 sq. ft of veg?
Click to expand...
50-70
 
S

Safehaven

Active Member
The setup I referenced above uses 4 COBs to produce 110 PAR W for 6 sq. ft. If I were flowering in a 4x8 space, I would need 6 of the above fixtures, for a total of 24 COBs.

If I am looking for 50-70 PAR W for veg, wouldn't that mean that I would need to halve the setup above, for a total of 55 PAR W?

Am I correct in thinking that I would need 12 COBs, which is more than the 8 I originally thought?

Maybe my math is screwy?
 
littlejacob

littlejacob

Well-Known Member
Bonjour
You will need 15/20w sq/ft for vegg with cxb3590 5000ºk DB!
So 4x8= 32×20w=640w...
So 3 x 4 cxb 3590 36V @1400mA...about 1100 $!
But you will grow nice healthy and bushy plants with it!
CU
 
BOBBY_G

BOBBY_G

Well-Known Member
make sure you understand par watts = watts x efficiency

so a cob that uses 50W @ 60% efficiency = 30 PAR watts

generally 20 par watts /sf for flowering and 10 for veg are adequate
 
S

Safehaven

Active Member
Thanks for clarifying PAR W. I don't think I was understanding it quite right.

Nevertheless, I think my math was still correct in that I would need 12 COBs running at 49W for a total of 588W for the space.

Just for learning purposes, since T5s are less efficient, would I need more total watts for the space?
 
BOBBY_G

BOBBY_G

Well-Known Member
well assuming youre only lighting 32SF (not hard to get some reflective plastic or foamboard up in there to reduce the room size, also directional lenses/reflectors on the cobs will help you keep the light on the canopy

12 cobs @ 49W (aka 56% efficiency) = 588*.56 = 329 W / 32 SF = just over 10 par W/ SF

and yes on T5s theyre about 100 lumens/watt vs your 182 lumens/watt on your cob at 49W so youd need almost twice as many - and youd be throwing off a lot more heat
 
ttystikk

ttystikk

Well-Known Member
FWIW, I'll be lighting my veg with CXB3590 5000k DB @50W. I'll be using one 200W module per 4' x 6' growing space. They should handily outperform my HID lights for roughly half the watts expended.
 
BOBBY_G

BOBBY_G

Well-Known Member
ttystikk said:
FWIW, I'll be lighting my veg with CXB3590 5000k DB @50W. I'll be using one 200W module per 4' x 6' growing space. They should handily outperform my HID lights for roughly half the watts expended.
Click to expand...
am i missing something? sounds low?

200w/24 SF = 8.3 W/SF = 4.67 PAR W/SF
 
littlejacob

littlejacob

Well-Known Member
Sound too low my friend...4 cxb over 4x6...24sq/ft X 15 w = 360w...
I am not sure it will be enough even with the best spread possible...maybe 250w is possible!? But 200 I doubt...
CU
 
S

Safehaven

Active Member
So, I have made my final decision to veg in a 3'x8' area to start. The beauty of the COBs is that I can expand if I need to later.

By my calculations, I need 8 COB's.

Two questions:

1. Which bins are the top bins for CXB3590 4000K and CXB3590 5000K?

2. 4000K vs 5000K, is one a better choice than the other, or will the perform about the same?
 
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