Custom COB light setup

Rahz

Rahz

Well-Known Member
After thinking about this I'm going to take back my comment on the 24" square. That would center them over the outer square feet but at 6" from the walls and minimum 12" from canopy that will be a lot of light hitting the walls. A 4 cob lamp I would run the spacing about 14" corner to corner. For an 8 cob lamp I'm thinking give them at least 8-10 inches from the wall so a 16-20" square.

This has really been bugging me. This level of intensity in a small tent from 70 watt cobs isn't something I've pondered before. Anyone else have any input? @CobKits ?

That may not leave room for the drivers, but they could be remote mounted outside the tent, 14g stranded to the frame on Wagos then 18 or 20 AWG for connecting cobs. Would keep the heat down a bit anyway.

Also, if you're using reflectors you will want the non SE version.

Also, 18 AWG will require you to dremel out a bit of the reflector holders so it sits flush on the cob. 20 AWG will work without material removal. People generally like to use 18 AWG but 20 gauge 300V wire will will do the job fine.
 
CobKits

CobKits

Well-Known Member
Rahz said:
This has really been bugging me. This level of intensity in a small tent from 70 watt cobs isn't something I've pondered before. Anyone else have any input? @CobKits ?
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in a 3x3 with lights blasting that hard he will be way up off the canopy anyway, prob 24" so cob spacing isnt so critical. I have 9 luminus in a 3x3 (albeit at 30W/cob) and i believe they are on a 24" frame. super uniform at 18" to canopy
 
Marky Bluntz

Marky Bluntz

Member
I made a simple template of my light setup I decided to go with thanks to Rahz. It's a 24"x24" frame with 8 COBs around the edges. The size of the circles I made are very close to the identical sizes of the 140mm pin heatsinks and Vero 29 COBs. The COB circles are spot on (1.9") while the heatsink circles are a tad bigger (5.7" instead of the actual 5.5"). The center of each COB is spaced 8.5" away from each other.

I didn't know the heatsinks or the COBs were so large until I made this template. I can see why people said I was crazy with my original 12 COB plans for the 3x3 tent lol. I thought they were much smaller.

You guys think this setup looks good or should I change some things? I wanted to do a 3x3 grid in a 30"x30" frame but decided to do a 8 COB 24"x24" square after it was suggested to me.
 

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Marky Bluntz

Marky Bluntz

Member
Don't get me wrong @Rahz , if 8 COBs is too much for a 3x3 tent I'm willing to reduce the number. I just thought with a dimmer I can maximize photons in the tent while keeping the heat under control. I could run the 8 COBs at 700ma which will run them at 50w each. Or I could go with a stronger current with less COBs. My main goal is to give my plants more than enough light so they thrive in it.
 
Rahz

Rahz

Well-Known Member
So 17" from cob to cob horizontally? Yea I think that might be a good bet.

You're trying to tamp down the hot spot in the center while also keeping as much light off the walls as possible. You could build a temporary rig and do some testing with a cheap lux meter before locking things down. Lower and wider -vs- higher and tighter. I'm not sure where the perfect spacing/height would be in that setup.

As far as the wattage per cob, I think overkill is cool if that's what you're after and can always be dimmed. If you ran with 45.3 watts per cob (700ma) that would put your PPFD around 1200 which would still be kick ass and you could do it with a couple HLG-185H-C700Bs. But if you're wanting to see how far you can push things I would stick with the 1050ma current because that will definitely take you to the edge. You may still dim but you might end up happy running them at 60w each or something.

It just depends on what you're trying to accomplish. If I had 600 watts to play with I would much rather run 2 3x3 tents at 800 PPFD rather than one tent at 1600 PPFD. Back when I grew doing DWC I was pulling almost 60 grams per square foot with PPFD under 800.
 
Marky Bluntz

Marky Bluntz

Member
Rahz said:
So 17" from cob to cob horizontally? Yea I think that might be a good bet.

You're trying to tamp down the hot spot in the center while also keeping as much light off the walls as possible. You could build a temporary rig and do some testing with a cheap lux meter before locking things down. Lower and wider -vs- higher and tighter. I'm not sure where the perfect spacing/height would be in that setup.

As far as the wattage per cob, I think overkill is cool if that's what you're after and can always be dimmed. If you ran with 45.3 watts per cob (700ma) that would put your PPFD around 1200 which would still be kick ass and you could do it with a couple HLG-185H-C700Bs. But if you're wanting to see how far you can push things I would stick with the 1050ma current because that will definitely take you to the edge. You may still dim but you might end up happy running them at 60w each or something.

It just depends on what you're trying to accomplish. If I had 600 watts to play with I would much rather run 2 3x3 tents at 800 PPFD rather than one tent at 1600 PPFD. Back when I grew doing DWC I was pulling almost 60 grams per square foot with PPFD under 800.
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I know most people go with 4 COBs in a 3x3. I'm basically going with double the amount of light. What do you think of 5 COBs on a square frame with 1 on each corner and 1 in the middle? Or 6 COBs in a 2x3 grid on a square frame?

I'm aiming for optimal lighting. Slightly overkill but not to the point where I have to keep my fixture so far away from the plants that there's more light hitting the walls than the canopy. I'm only growing 4 plants in that tent at a time using the manifold method.
 
Rahz

Rahz

Well-Known Member
I would consider 1200PPFD slightly overkill which you will get running 8 at the 700ma current.

Bonuses:

Use 2 HLG-185H-C700B and at max current your drivers will run more efficiently than dimming the 320s down to the same level.
Use the same heat sinks you would have used. You cobs will run cooler.
Your efficiency at max current will be in the high 50s.

You could always save a bit of money going with a 5 or 6 cob rig, but the overall cost isn't an arm and a leg more to build something you will look at 3-4 years from now and still be happy with the efficiency. Plus the money you save in electricity over that period will basically pay for the extra cobs.

Up to you though. It's a lot to consider. I always enjoyed working on a new design and stressing over the details.
 
Marky Bluntz

Marky Bluntz

Member
Rahz said:
I would consider 1200PPFD slightly overkill which you will get running 8 at the 700ma current.

Bonuses:

Use 2 HLG-185H-C700B and at max current your drivers will run more efficiently than dimming the 320s down to the same level.
Use the same heat sinks you would have used. You cobs will run cooler.
Your efficiency at max current will be in the high 50s.

You could always save a bit of money going with a 5 or 6 cob rig, but the overall cost isn't an arm and a leg more to build something you will look at 3-4 years from now and still be happy with the efficiency. Plus the money you save in electricity over that period will basically pay for the extra cobs.

Up to you though. It's a lot to consider. I always enjoyed working on a new design and stressing over the details.
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Ok so 8 COBs at 700ma sounds like a plan. I'm just a bit stuck with the frame size and COB layout. Should I stick with the 24"x24" frame with the COBs around the edges? I made a template, I'm not sure if you saw it.
 
Marky Bluntz

Marky Bluntz

Member
Off topic but I'm pretty bummed out I can't "like" any posts. I use my smartphone all the time and I don't see the option to like posts. I don't even see any signatures.
 
Jimmyclone42

Jimmyclone42

Well-Known Member
I have 2 of these panels.. I have an 8*8 tent, but only use about a 4*8 section for plants.. Mine are spaced around 15" apart.6x 3500/80cri and 2x 2700/90cri per panel. I run 2 hlg240-1750's on each 20170524_220104.jpg 20170701_224247.jpg 20170501_231045.jpg panel and pull about 490w per panel on max.. Just under 1000w between the 2.. I have had great results with this setup.. Will never go back to hps..
 
Marky Bluntz

Marky Bluntz

Member
Rahz said:
Yea I think that will do a good job.
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Ok. I will figure out spacing and distance once I have the tent and lights set up so I can do a dry run with a light meter and see what the sweet spots are.

Just a thought since I started reading about quantum boards and I see many people mixing them with COBs. Would it make sense to, let's say, use 4 COBs (1 on each corner) and add 1 or 2 quantum boards in the middle? It's only a thought. I'm curious if it'll actually benefit anything by mixing the two. I personally don't see why people mix them besides them being additions to already existing light setups by those who want more light.
 
Marky Bluntz

Marky Bluntz

Member
Rahz said:
They fit but not made for SE using holders.
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So you're saying they will fit the SE model chips but not the regular chips with the SE holders? Or they won't fit anything SE period? I was going to get the Vero 29 SE model chips to make removing and adding COBs on my rig more convenient. I don't mind soldering though. I do tons of soldering with the circuit boards I build and sell for RC cars and planes.
 
Rahz

Rahz

Well-Known Member
Marky Bluntz said:
So you're saying they will fit the SE model chips but not the regular chips with the SE holders? Or they won't fit anything SE period? I was going to get the Vero 29 SE model chips to make removing and adding COBs on my rig more convenient. I don't mind soldering though. I do tons of soldering with the circuit boards I build and sell for RC cars and planes.
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They will mount but won't sit flush on the chips.
 
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