New LED Grow - Advice Needed

Hello. I am planning to build a new grow room and I would appreciate some advice.

I've done a fair amount of research but there are still some things I don't understand. Technical terms, maths and physics are fine by me.

Grow space size = approx 13ft x 13ft (4m x 4m) but i don't need to use all the space immediately

What do you think of this setup for veg growing...

50x Cree CXB3590 4000K 70CRI DD 36V
50x Cree CXB3590 5000K 70CRI DD 36V
Mixed together and distributed evenly.

Run on 10x Meanwell HLG-240H-C700B (10 cobs per driver, wired in series, each cob gets 700mA of current)

I chose this setup because the lower current means less heat loss, and higher efficiency.
Also 10 cobs fit nicely onto one driver, with no voltage left over at the end.
Also i guess the cobs will last longer when run at a lower current.

From what I've seen most people seem to be running their COBs at 1400mA or more.
Also the graphics on Cree's info docs don't go below 1400mA, which is not helpfull.

Ok fine, but now some questions...

How much power would each driver be pulling from the wall with this setup?
>How do you work this out?
>Equations please if you have them.

How do I work out the efficiency of this setup?
>What percentage goes to light and heat?
>Again how to & equations welcome.

How much light would each COB be producing at 700mA?
>Over what area?
>Has anyone mapped this before?

How much space could I cover with this light setup?

Are people still using Cree's or is there something better?

Is it worth investing in COBs or should i go straight to quantum board?

Thanks in advance.

chilledbean said:

Are people still using Cree's or is there something better?

Click to expand...

This is a source of great debate. That aside, I contend if you have the willingness to drop the level of cash needed for that many cobs, a good move would be to look at Cobkits.com.
He's also an advertiser on this site.

That's a lot of $$$ to invest. I'd go with CMH just based on cost, but it sounds like you are committed to LED.. CobKit's will have all of the info you need to achieve your goal... Vero 29 is another option. GrowMau5 has a large CXB setup on youtube and i believe he gives the details of how he set it up..

Yeah I watched a lot of Growmau5 videos, and Migrow, and Bruce Bugbee.... but no one seems to talk about going below 1400mA.

I am pretty commited to LEDs now. It's a big start up cost but these things should last years if looked after. And they're pretty efficient.

Curious... why did you skip over quantum board led's and go to cob led? QB's have a better spread and are slightly cheaper and equally as efficient, maybe better?

CXB3590DB36V4000K 1 COBS @0.7A ON 1.813 PROFILE HEATSINK
1 SQ.FT. CANOPY 95% EFFICIENT DRIVER @11 CENTS PER KWH
Total power watts at the wall: 24.21
Cobs power watts: 23
Total voltage forward: 33
Total lumens: 5152
Total PAR watts assuming 10% loss: 14
Total PPF: 63.42
PPFD based on canopy area: 682.65
PAR watts per sq.ft.: 14.0
Cob efficiency: 69.34%
Power watts per sq.ft.: 23.0
Voltage forward per cob: 32.72
Lumens per watt: 223.98
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: 7
umol/s/W / CRI: 4.53 / 70CRI
Heatsink length passive cooling @120cm^2/heatwatt: 8 inches
Heatsink length active cooling @40cm^2/heatwatt: 3 inches
COB cost dollar per PAR watt: $3.58
Electric cost @12/12 in 30 days: $1.46
Electric cost @18/6 in 30 days: $1.94
Cost per cob: $50.17
Heatsink cost per inch cut: $0.66
Total cobs cost: $50
Total heatsink passive cooling cost: $5
Total heatsink active cooling cost: $1

CXB3590DB36V4000K 1 COBS @1.05A ON 1.813 PROFILE HEATSINK
1 SQ.FT. CANOPY 95% EFFICIENT DRIVER @11 CENTS PER KWH
Total power watts at the wall: 37.89
Cobs power watts: 36
Total voltage forward: 34
Total lumens: 7712
Total PAR watts assuming 10% loss: 21
Total PPF: 95.13
PPFD based on canopy area: 1023.97
PAR watts per sq.ft.: 21.0
Cob efficiency: 66.32%
Power watts per sq.ft.: 36.0
Voltage forward per cob: 33.85
Lumens per watt: 214.22
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: 12
umol/s/W / CRI: 4.53 / 70CRI
Heatsink length passive cooling @120cm^2/heatwatt: 14 inches
Heatsink length active cooling @40cm^2/heatwatt: 5 inches
COB cost dollar per PAR watt: $2.39
Electric cost @12/12 in 30 days: $2.0
Electric cost @18/6 in 30 days: $2.75
Cost per cob: $50.17
Heatsink cost per inch cut: $0.66
Total cobs cost: $50
Total heatsink passive cooling cost: $9
Total heatsink active cooling cost: $3

Here are two examples , first running at 700mA second at 1050mA , with the second you could use one cob per square foot so 100 cobs, 100 square foot.

The data is based on the diycobcalc , some of it like pricing is way out of date, but it gives you a rough idea.

Cob calc can be found here
https://www.rollitup.org/t/diy-cob-led-calculator.890214/page-14#post-14701729
Use the link in bggrass 's signature, below any of his posts. You need java to run it.

I would talk to cobkits though , I think there are better options these days, the cree is still expensive and improvements in other brands have been made since the 3590 was the go to cob.
I would also look at boards and strips and price compare.

Did you ever look at DIY quantum boards?

jjng5 said:

QB's have a better spread and are slightly cheaper and equally as efficient, maybe better?

Click to expand...

None of this is absolute fact. All based on application, and quantity.

Do you want yield or quality? Thats the first thing you want to distinguish.

If its yield buy QB's.

I personally think for a larger area a COB LED setup is the way to go. For a smaller area the quantum boards. Either way you want a minimum of 35 true watts per sqft.

Personally I would go with CMH to get the UV light for added resin production.

Wall to wall strips no heatsinks required if you run them soft.

Renfro said:

I personally think for a larger area a COB LED setup is the way to go. For a smaller area the quantum boards. Either way you want a minimum of 35 true watts per sqft.

Personally I would go with CMH to get the UV light for added resin production.

Click to expand...

To get primo buds, without a primary need of max quantity I'd go CMH with HPS added in flower. resiny, dense nuggs

From my research it looks like QB or Cob Crees combine decent quality with fantastic yields. If you plan on makin $$ this is your best bet.

If your grow is to meet your personal high standards (huge yield not needed) I'd use CMH with HPS in flower added

Couch_Lock said:

To get primo buds, without a primary need of max quantity I'd go CMH with HPS added in flower. resiny, dense nuggs

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Agreed. CMH and HPS together is a banging combo. Works best with high ceilings so the different lights can blend better.

Another good way to go is HPS with a MH finishing bulb at the very end of flowering.

LED lighting is great I just want more UV myself. The CMH and MH give a lot of that. The HPS has the far red on lock IMO. A good blend of CMH and HPS has the best of the far red and the UV. Would be cool to have a fixture with a 600w DE HPS and a 600 watt DE CMH all in one reflector. lol Would need two ballasts though.

Couch_Lock said:

If its yield buy QB's

Click to expand...

Again, based on application, not necessarily fact.

They are undoubtedly the most efficient lights around, Chip. If the same grower (using same methods), used a variety of lighting types, the "application" theory would not hold up.

Check out "Soil2Coco" 's QB grows at Grasscity. Fella is not far from me.

chilledbean said:

50x Cree CXB3590 4000K 70CRI DD 36V
50x Cree CXB3590 5000K 70CRI DD 36V

Click to expand...

Why the 5000K? I would think a 3500K for all would be good, or perhaps a mix of 3000K and 4000K.

34 Cree cxb3590 2700K 90 cri
33 Cree cxb3590 3500K 80 cri
33 Cree cxb3590 5000K 70 cri

Hella money but probably a killer spectral setup. Tight internodes (blues), lots of red for flower.

Couch_Lock said:

They are undoubtedly the most efficient lights around, Chip. If the same grower (using same methods), used a variety of lighting types, the "application" theory would not hold up

Click to expand...

Well since that grower is me, and in fact there ARE possible setups for certain emitters, to run at higher efficiencies than QBs, the application theory, is only a theory to you, not me.

Getting back to the OP, setting up a room that size your options are limitless. Bulk purchases of components are an advantage for setup cost.