Cob LED question

[Checkit71]

so I am looking at a diy kit in my 4x4. So the I'm wondering if you guys can help me chose between the kits. Either doing 8x3590's COBs @ 600 watts or 10 running @500watts. I know everyone talks about having more light sources I just can't tell if more sources is better than more watts. Also is the penetration of these lights increased with the higher watts? Also planing on doing half in 3500k and the other half in 500k, is that a good idea or just running all 3500k? Thanks for the info guys . It's been a tough call between these or LEC's but I'm finally going to pull the trigger on COB's in the next month

 

[MeGaKiLlErMaN]

Color diversity hasnt been super tested in a scientific way, but it cant hurt. I personally cant help with that. However Im running at the 4000K in an attempt to get better efficiency and still use them for flowering. If youre just starting out go with the cheaper option. Are you using the passive pin heatsinks? if so they are good up to 50W. The rule of thumb for the best set up is 1 cob per sq/ft. Use the calculator attached to get the best PPFD in the area for your preferred price point . (you need to extract it and install Java so you can run it Right click open with java)

 

[Checkit71]

Gotcha thanks for the input. I just remember back when I had a Mars and before that some ufos those plants produced a of frost compared to my hps. That's why I was thinking of running the 5000k for more of those blues to help frost it up but maybe the 4's might be better.

 

[Uberknot]

hmm....If you are going to run them higher watts I think you can get away with less cobs.

 

[Checkit71]

And that's pretty much what I'm trying to figure out. I want to run that program but I'm only on my cell at the moment so I can't calculate right now. They are the timber diy kits and they are the same price.

 

[Uberknot]

And that's pretty much what I'm trying to figure out. I want to run that program but I'm only on my cell at the moment so I can't calculate right now. They are the timber diy kits and they are the same price.

Well if you can get 35 watts or more per square foot coverage you should be good.

 

[Rahz]

600w from 8 should provide about 300 PAR watts.
500w from 10 should provide about 280 PAR watts.

 

[MeGaKiLlErMaN]

I just ran it for you: heres your first situation (ignore the cost for heatsinks.. idk what youre using):

Btw both are more efficient than a DE HPS. but after looking at this I think that the 1st option is better just based off of the PPFD for the initial money.

CXB3590CD36V3500K 8 COBS @2.1A ON 1.813 PROFILE HEATSINK
16 SQ.FT. CANOPY 94% EFFICIENT DRIVER @10.5 CENTS PER KWH
Total power watts at the wall: 642.55
Cobs power watts: 604
Total voltage forward: 288
Total lumens: 97280
Total PAR watts assuming 10% loss: 270
Total PPF: 1255.5
PPFD based on canopy area: 844.63
PAR watts per sq.ft.: 16.88
Cob efficiency: 49.71%
Power watts per sq.ft.: 37.75
Voltage forward per cob: 35.97
Lumens per watt: 161.06
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: 304
umol/s/W / CRI: 4.65 / Estimated
Heatsink length passive cooling @120cm^2/heatwatt: 361 inches
Heatsink length active cooling @40cm^2/heatwatt: 120 inches
COB cost dollar per PAR watt: $1.41
Electric cost @12/12 in 30 days: $24.79
Electric cost @18/6 in 30 days: $36.93
Cost per cob: $47.62
Heatsink cost per inch cut: $0.66
Total cobs cost: $381
Total heatsink passive cooling cost: $238
Total heatsink active cooling cost: $79

Second EX:

CXB3590CD36V3500K 10 COBS @1.4A ON 1.813 PROFILE HEATSINK
16 SQ.FT. CANOPY 94% EFFICIENT DRIVER @10.5 CENTS PER KWH
Total power watts at the wall: 519.15
Cobs power watts: 488
Total voltage forward: 349
Total lumens: 89080
Total PAR watts assuming 10% loss: 247
Total PPF: 1148.55
PPFD based on canopy area: 772.68
PAR watts per sq.ft.: 15.44
Cob efficiency: 56.34%
Power watts per sq.ft.: 30.5
Voltage forward per cob: 34.89
Lumens per watt: 182.54
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: 213
umol/s/W / CRI: 4.65 / Estimated
Heatsink length passive cooling @120cm^2/heatwatt: 253 inches
Heatsink length active cooling @40cm^2/heatwatt: 84 inches
COB cost dollar per PAR watt: $1.93
Electric cost @12/12 in 30 days: $20.12
Electric cost @18/6 in 30 days: $29.94
Cost per cob: $47.62
Heatsink cost per inch cut: $0.66
Total cobs cost: $476
Total heatsink passive cooling cost: $167
Total heatsink active cooling cost: $55

 

[Checkit71]

Thanks a bunch for running that for me def helped with choosing from the 2. I guess the last decision is to figure out if mixing 3500's and 5000's are worth it or just doubling up on 3500's.