Advice on a cob build

visajoe1

visajoe1

Well-Known Member
KushyMcKush said:
Thats some very cool info! Thank you. So maybe it might be a good idea to go active cooling just in case? Or will it be fine on those sst-x Ive been eyeballing? Im really considering this. With that driver they would be just around 1600ma correct? Thats a lot of light.
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To run three 1818's parallel at 1600, you would need more than one driver, so you would want to run 4 actually. You would need 2 HLG 185-48a models, max amperage on this driver is 3.9a. Remember, the 1818 requires 50v. I would not recommend this setup.

Or, you could run 3 in series with a HLG240-1400, but it would be at 1400 and not 1600.

Or, you could run 3 in series with a HLG320-1750.

Still, though, these dont perform as well as your option #1.

The three 1818's you mentioned in post #13 are running at 1300
 
KushyMcKush

KushyMcKush

Well-Known Member
visajoe1 said:
To run three 1818's parallel at 1600, you would need more than one driver, so you would want to run 4 actually. You would need 2 HLG 185-48a models, max amperage on this driver is 3.9a. Remember, the 1818 requires 50v. I would not recommend this setup.

Or, you could run 3 in series with a HLG240-1400, but it would be at 1400 and not 1600.

Or, you could run 3 in series with a HLG320-1750.

Still, though, these dont perform as well as your option #1.

The three 1818's you mentioned in post #13 are running at 1300
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Lol yea I figured out that was 1300ma not 1600 after I posted that I looked at the driver specs again. Math... its not a strong suit.
Someone on another thread seems to think the 4 1212's on the 240-1750 wont work well because they would be running at 37.5v and would be 150v and the max fv on that driver is 143v. He seems to think that would be "tickling the over voltage cicuit." Essentially putting me too close. I don't think i can find the 1212 anyways, so that may not be an option for me. The 4 or 5 places Ive checked are out of stock. 1818 is easy to get... or just go with vero29 in the same set up as the 1212's. It will be a little more but at least Ill be using a 36v chip, which seems like the popular voltage and easy to upgrade when a new gen comes out. Right? Maybe?
 
KushyMcKush

KushyMcKush

Well-Known Member
1400ma or even 1300 would still be putting out a lot of light on those big 1818's. The numbers seem to be comparable to the major 36v chips (3590, 1212, vero29), around 1050ma, so Id Imagine 6 of those running at that current would be pretty damn bright. My area is only 4x5... maybe even keeping it to 4x4, so I mean bars of 3 would put me at one every 12" or so... again...math.
 
visajoe1

visajoe1

Well-Known Member
Yes, I would lean towards 36v chips, you have more options and ability to upgrade later. I have a couple 1818's in a drawer cuz it would throw my whole light canopy out of whack. I would prefer to use them! But, I've spent enough cash already and what I have is killin it, so if it aint broke, dont fix it. right? lol. The 50v chips can only use a few diff drivers. If the 36v vero's are more available to you, I would go with that.

Anything you can do to keep the heatsinks cool, even passive ones, will help. Its safer and your equipment will thank you

Cobkits.com has 1212's in stock
 
visajoe1

visajoe1

Well-Known Member
KushyMcKush said:
1400ma or even 1300 would still be putting out a lot of light on those big 1818's. The numbers seem to be comparable to the major 36v chips (3590, 1212, vero29), around 1050ma, so Id Imagine 6 of those running at that current would be pretty damn bright. My area is only 4x5... maybe even keeping it to 4x4, so I mean bars of 3 would put me at one every 12" or so... again...math.
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Meh, six 1818's at 1300 over 14sq ft (cuz your also using your 315) is only 460ppfd. The eight 1212's at 1750 gives you 755ppfd.
Both setups require two drivers
 
ledgardener

ledgardener

Well-Known Member
visajoe1 said:
Yes, I would lean towards 36v chips, you have more options and ability to upgrade later. I have a couple 1818's in a drawer cuz it would throw my whole light canopy out of whack. I would prefer to use them! But, I've spent enough cash already and what I have is killin it, so if it aint broke, dont fix it. right? lol. The 50v chips can only use a few diff drivers. If the 36v vero's are more available to you, I would go with that.

Anything you can do to keep the heatsinks cool, even passive ones, will help. Its safer and your equipment will thank you

Cobkits.com has 1212's in stock
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Agreed. I'd go 36V for flexibility.

And yeah OP I think it makes more sense to go constant current if you're new to electronics. They're much more forgiving.

Check out this constant current driver calculator if you haven't seen it already - it'll make it easier to compare options.
 
KushyMcKush

KushyMcKush

Well-Known Member
visajoe1 said:
Yes, I would lean towards 36v chips, you have more options and ability to upgrade later. I have a couple 1818's in a drawer cuz it would throw my whole light canopy out of whack. I would prefer to use them! But, I've spent enough cash already and what I have is killin it, so if it aint broke, dont fix it. right? lol. The 50v chips can only use a few diff drivers. If the 36v vero's are more available to you, I would go with that.

Anything you can do to keep the heatsinks cool, even passive ones, will help. Its safer and your equipment will thank you

Cobkits.com has 1212's in stock
Click to expand...
Ohhh derp... I was only looking at the 3500k gen 6. I could do the 3000k but its not gen6. The gen 6 looks slightly better on the data sheet, but for a $12 chip you can't be that picky huh? Lol.
So yea, it looks like I should I should stick with the 36v definitely because I just know Im going to keep replacing with the newest and best as I go lol. I can already see that happening. Btw I can get the vero29 for $30. I can't remember if someone asked that :shock: So I guess that widdles my decision down to citi 1212 or vero29.

Ok, so will the 1212 work on the 250-1750 or no? Is it pushing that driver dangerously close to its max? Would the vero29 fit better? (Ill check out that calculator right now).

@ledgardener Thanks, that will definitely help! I agree, keep it simple. Ill stick with that.
 
visajoe1

visajoe1

Well-Known Member
KushyMcKush said:
Ohhh derp... I was only looking at the 3500k gen 6. I could do the 3000k but its not gen6. The gen 6 looks slightly better on the data sheet, but for a $12 chip you can't be that picky huh? Lol.
So yea, it looks like I should I should stick with the 36v definitely because I just know Im going to keep replacing with the newest and best as I go lol. I can already see that happening. Btw I can get the vero29 for $30. I can't remember if someone asked that :shock: So I guess that widdles my decision down to citi 1212 or vero29.

Ok, so will the 1212 work on the 250-1750 or no? Is it pushing that driver dangerously close to its max? Would the vero29 fit better? (Ill check out that calculator right now).

@ledgardener Thanks, that will definitely help! I agree, keep it simple. Ill stick with that.
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Your data for eight 1212's 3500k, 90cri gen 5, at 1750. Gen 6 should give you additional ppfd, but now sure how much. Voltage per driver would be 144.75, which wont cause any problems.

1212 3500K90Min 8 COBS @1750 mA ON 1.813 PROFILE HEATSINK
14 SQ.FT. CANOPY 94% EFFICIENT DRIVER @13 CENTS PER KWH
Total power watts at the wall: 539.45
Cobs power watts: 507.08
Total voltage forward: 289.76
Total lumens: 55818.26
Total PAR watts assuming 10% loss: 149.96
Total PPF: 801.45
PPFD based on canopy area: 616.20
PAR watts per sq.ft.: 10.71
Cob efficiency: 32.86%
Power watts per sq.ft.: 36.22
Voltage forward per cob: 36.22
Lumens per watt: 110.08
Heatsink riser thickness / number of fins / fin's length: 0.3in/6/0.95in
Heatsink area per inch: 100.94 cm^2
Total heat watts: 339.75
umol/s/W: 1.58 LER: 335.00 QER: 4.81
Heatsink length passive cooling @120cm^2/heatwatt: 404 inches
Heatsink length active cooling @40cm^2/heatwatt: 135 inches
COB cost dollar per PAR watt: $0.64
Electric cost @12/12 in 30 days: $25.25
Electric cost @18/6 in 30 days: $37.87
Cost per cob: $12.0
Heatsink cost per inch cut: $0.66
Total cobs cost: $96.0
Total heatsink passive cooling cost: $266.64
Total heatsink active cooling cost: $89.10
 
nevergoodenuf

nevergoodenuf

Well-Known Member
If you are looking for the easiest setup for around your CMH in that area, I would do this:
4 CLU058 1825
1 HLG320H54B
and for safety and efficacy use a heatsink that can protect each COB at 160w.
This setup will also allow for easy changes down the road.
 
SSGrower

SSGrower

Well-Known Member
ledgardener said:
I've been doing some testing on parallel/constant voltage setups lately to see if I could get COBs to go thermal. I found that they were very stable until I threw a ton of current at them (like 3 Amps), at which point they did go into thermal runaway on me.

Interestingly enough, when I increased cooling on my heat sink by pointing a by fan at it, I was able to prevent thermal runaway, even at 3 Amps into a CXB3590.

I have been running 2 Veros in parallel on a constant voltage driver at their typical current for a couple weeks now though and they are 100% stable.
Click to expand...
for cree there is a spec sheet that shows what temp vs. current the chips can handle graph page 2. I set up a heatsink with thermostat directly behind where the cob mounts, compared to Tj readings were within a couple of degrees.
 

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KushyMcKush

KushyMcKush

Well-Known Member
visajoe1 said:
Your data for eight 1212's 3500k, 90cri gen 5, at 1750. Gen 6 should give you additional ppfd, but now sure how much. Voltage per driver would be 144.75, which wont cause any problems.

1212 3500K90Min 8 COBS @1750 mA ON 1.813 PROFILE HEATSINK
14 SQ.FT. CANOPY 94% EFFICIENT DRIVER @13 CENTS PER KWH
Total power watts at the wall: 539.45
Cobs power watts: 507.08
Total voltage forward: 289.76
Total lumens: 55818.26
Total PAR watts assuming 10% loss: 149.96
Total PPF: 801.45
PPFD based on canopy area: 616.20
PAR watts per sq.ft.: 10.71
Cob efficiency: 32.86%
Power watts per sq.ft.: 36.22
Voltage forward per cob: 36.22
Lumens per watt: 110.08
Heatsink riser thickness / number of fins / fin's length: 0.3in/6/0.95in
Heatsink area per inch: 100.94 cm^2
Total heat watts: 339.75
umol/s/W: 1.58 LER: 335.00 QER: 4.81
Heatsink length passive cooling @120cm^2/heatwatt: 404 inches
Heatsink length active cooling @40cm^2/heatwatt: 135 inches
COB cost dollar per PAR watt: $0.64
Electric cost @12/12 in 30 days: $25.25
Electric cost @18/6 in 30 days: $37.87
Cost per cob: $12.0
Heatsink cost per inch cut: $0.66
Total cobs cost: $96.0
Total heatsink passive cooling cost: $266.64
Total heatsink active cooling cost: $89.10
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Thats awesome man thanks! Some of those numbers seem low though... 110lm/w, 1.58 umols/w, 32% efficiency? Those seem low just based on numbers Ive been seeing around. I though I wanted around 1.8umol/w or even, 140+lm/w... these are roughly the numbers Ive been lead to belive are considered good. No? If I stick to a 4x4, with the 315, that would bump those numbers up because it would be filling a smaller area. Right? Idk, my head hurts lol.
 
Joe34

Joe34

Active Member
Kushy I updated my post to include a link to the Vero 29 for cheaper too...
And the Citi link is for verion 5 1212's, although try a search on that site they mite have ver 6
 
visajoe1

visajoe1

Well-Known Member
KushyMcKush said:
Thats awesome man thanks! Some of those numbers seem low though... 110lm/w, 1.58 umols/w, 32% efficiency? Those seem low just based on numbers Ive been seeing around. I though I wanted around 1.8umol/w or even, 140+lm/w... these are roughly the numbers Ive been lead to belive are considered good. No? If I stick to a 4x4, with the 315, that would bump those numbers up because it would be filling a smaller area. Right? Idk, my head hurts lol.
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LOL, ya man, this stuff gets confusing when you get wrapped up in it. It will get clearer the more you are familiar with it. Lotta folks around to help too. You are correct, numbers are on lower end, but its because of the higher current. My gen 5 1212's run at 1.2a and are 44% efficient (43.79) and 143lm/w.

Forget about lm/w right now. That correlates with efficiency. PPFD is what you need to dial in



nevergoodenuf said:
If you are looking for the easiest setup for around your CMH in that area, I would do this:
4 CLU058 1825
1 HLG320H54B
and for safety and efficacy use a heatsink that can protect each COB at 160w.
This setup will also allow for easy changes down the road.
Click to expand...
This gives 560ppfd
 
Chronikool

Chronikool

Well-Known Member
'Luminus' COBs are also an option if you are looking at budget and performance.

Loving mine, and i also run citizen and cree. (Maybe bridgelux next year..haha)

$19

On par with the 1818s....

Cobkits.com
 
KushyMcKush

KushyMcKush

Well-Known Member
visajoe1 said:
LOL, ya man, this stuff gets confusing when you get wrapped up in it. It will get clearer the more you are familiar with it. Lotta folks around to help too. You are correct, numbers are on lower end, but its because of the higher current. My gen 5 1212's run at 1.2a and are 44% efficient (43.79) and 143lm/w.

Forget about lm/w right now. That correlates with efficiency. PPFD is what you need to dial in





This gives 560ppfd
Click to expand...
Ok, so this may be an incredibly dumb question, and Im sure Im misunderstanding something here. 200w is 200w right? I mean if Im running 160lm/w on 200w vs. 110lm/w on 200w... obviosuly 160x200=32000lm and the is 22000lm. Again, Im probably missing something. Idk, maybe going something like 10 1212's on 240-1400's would be a better set up for a fist timer? Do the vero hold their efficiency better at 1750? Im not married to the 1750 current, it just seemed like the best way to get the most light without getting too hot and with fewer chips. I set my budget cap at $600, so whatever I need to do to get the best results Ill do it. I know ita tough with the 315 in there because its kind of an oddball variable.
 
KushyMcKush

KushyMcKush

Well-Known Member
Joe34 said:
Kushy I updated my post to include a link to the Vero 29 for cheaper too...
And the Citi link is for verion 5 1212's, although try a search on that site they mite have ver 6
Click to expand...
I saw that thanks man! Maybe they have the wrong data sheet linked? It looked like those numbers were gen6. Too tired to go look right now.

It seems like a lot of people really like vero29's. Would those get me better numbers on the same set up (@1750ma)?
 
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