COB efficiency Spreadsheets

SupraSPL

SupraSPL

Well-Known Member
In order to flower during the humid season I have shut down the outside air and run a dehumidifier and AC together to keep RH at least 60-65%. Make sure your ladies are getting non stop circulation fan 24/7 during the last 6 weeks of flowering. Over fertilizing can aggravate bud rot also.

Some varieties are more susceptible than others so if you can find a variety that is resistant that can help.
 
Last edited:
B

benbud89

Well-Known Member
Thanks for all the informative replies, both regards lighting, but also RH. Yes, it is a big problem. I really doubt that I overfertilize, I run 1200-1300 the entire flower cycle, and they never show any sign of stress or other issues. The hempy bucket may be an issue since I water everyday, I wouldnnt like to leave this method. I really like it...
 
B

benbud89

Well-Known Member
Would I be not just okay, but more than okay with 8 cxbs 3590 or 3070 in a 3x4? Im thinking of dobling my space. My heatsinks would only allow for at least one meter's depth. I really hope they will do for some passive cooling. The 3590 become more and more attractive with their cooler performance.
 
O

otonogatobasso

Member
doz said:
Top right of the page you linked, there is a drop down box for Current Range. Change that and you will have more options. I just put in CXB3070 w/ CB bin and was able to retrieve the numbers for everything.
Click to expand...
@doz, thank for your reply. I guess I used a bad example. With CXB3070 I get the same numbers as you. But what if we go to Cree's CPT tool again at http://pct.cree.com/dt/index.html and pick CXB3590 36V CB, the smallest current shown there is 1.400. How do you guys find the lumens and Watt info for lower current than the ones shown there?

Also, I keep finding people mentioning something like "this led has 42% efficiency". How is this calculated? I know this is such a dumb question, but I have been googling for a long time, and I can't seem to find an answer. Thanks!
 
nogod_

nogod_

Well-Known Member
Those numbers are from one of a few members here and they represent the lumens per watt @ a given current measured against the maximum lumens per watt the COB could possibly achieve.

The Cree datasheets offer this theoretical maximum and it is called the LER. For everything else someone like Alesh is calculating the LER for us using math that is way over my head.

So what we're doing is taking the lumens per watt either from the PCT or one of supra spreadsheets, and dividing that by the LER of the given chip to get the efficiency.

The number you get is not exact, but it tells you with relative certainty how much of the energy you feed into the chip is going to be emitted as visible light and how much is going to be radiated as heat before it even reaches the plant.

otonogatobasso said:
@doz, thank for your reply. I guess I used a bad example. With CXB3070 I get the same numbers as you. But what if we go to Cree's CPT tool again at http://pct.cree.com/dt/index.html and pick CXB3590 36V CB, the smallest current shown there is 1.400. How do you guys find the lumens and Watt info for lower current than the ones shown there?

Also, I keep finding people mentioning something like "this led has 42% efficiency". How is this calculated? I know this is such a dumb question, but I have been googling for a long time, and I can't seem to find an answer. Thanks!
Click to expand...
 
SupraSPL

SupraSPL

Well-Known Member
@otonogatobasso

Also keep in mind that the Cree PCT is using "minimum" lumen figures and is going by case temperature even though it says junction temperature, so the PCT lumen/W figures will be lower than the spreadsheets. The spreadsheets use "typical" figures and are assuming a junction temp of about 50C.
 
littlejacob

littlejacob

Well-Known Member
Bonjour
So to be clear a cxb 3590 @1400mA is 56%...ok
What is 100% and which diode is using as scale?
Because we compare each cob/diodes/cfl/t5/mh/hps to it!
Thanks
Have a great day ★
 
ttystikk

ttystikk

Well-Known Member
littlejacob said:
Bonjour
So to be clear a cxb 3590 @1400mA is 56%...ok
What is 100% and which diode is using as scale?
Because we compare each cob/diodes/cfl/t5/mh/hps to it!
Thanks
Have a great day ★
Click to expand...
It's beyond my attention span to track down and quantify each of the obsolete options, lol

100% efficiency = perfection = unachievable; it represents the 'perfect' conversion of watts into PPfd. I'm not very well versed in the physics of optics and LED so if I'm mistaken in anything I'm saying, others please chime in here.

Moving on; if let's say 56% of the watts being expended are converted into light, then the other 44% is converted into some form of heat. Okay, the first 56% becomes heat too, as soon as it lands on something. At least it's PPfd first and the plants can use it!

That's substantially better than HID lighting, where between sixty and seventy five percent of all electricity consumed is converted directly into heat, and only the remainder is PPfd.

This is why the only thing using more electricity than the lighting in a modern commercial grow warehouse is all of the environmental control equipment!
 
EfficientWatt

EfficientWatt

Well-Known Member
Hi LJ,

1) 100% efficient chip would not dissipate any direct heat. 56% efficient = 44% heat.
2) "Used for scale" :Itself : A 100% efficient HPS will not bet the same as a 100% efficient T5.. they are measured against their own SPD curve / spectrum.

littlejacob said:
Bonjour
So to be clear a cxb 3590 @1400mA is 56%...ok
What is 100% and which diode is using as scale?
Because we compare each cob/diodes/cfl/t5/mh/hps to it!
Thanks
Have a great day ★
Click to expand...
 
E

elninonino

Member
hi to all,

i found much nice info on this place.
So thank you for all that work you have done.

Im over my 4th led indoor grow at the moment,im doing mini grows and im downsizing everything atm.

My newest box is only 0.144m2 and only 0.6m tall.

Im using 4 "old" leds in that project.

2x Nichia NSCWJ216A sm503/G4050-G4850/R8000
2x Vero29 5000k
and added
2x new cree 3590 36v cb.

They are running at a mw-hlg120-c500a
dimmed to 250mA.

I dont find much info about that old Nichia LED.
Does someone has them added to their sheets ?
Im looking for their stats like effency/PAR at 250mA.
(calculating,if co2 addition is needed)


PS: Sry for my poor english
 
ttystikk

ttystikk

Well-Known Member
elninonino said:
hi to all,

i found much nice info on this place.
So thank you for all that work you have done.

Im over my 4th led indoor grow at the moment,im doing mini grows and im downsizing everything atm.

My newest box is only 0.144m2 and only 0.6m tall.

Im using 4 "old" leds in that project.

2x Nichia NSCWJ216A sm503/G4050-G4850/R8000
2x Vero29 5000k
and added
2x new cree 3590 36v cb.

They are running at a mw-hlg120-c500a
dimmed to 250mA.

I dont find much info about that old Nichia LED.
Does someone has them added to their sheets ?
Im looking for their stats like effency/PAR at 250mA.
(calculating,if co2 addition is needed)


PS: Sry for my poor english
Click to expand...
Sounds very interesting!

If your room is sealed, with no air in or out then you would do well with CO² supplementation. If your space is ventilated it will be a waste because it will not remain in with the plants long enough to do any good.
 
littlejacob

littlejacob

Well-Known Member
elninonino said:
hi to all,

i found much nice info on this place.
So thank you for all that work you have done.

Im over my 4th led indoor grow at the moment,im doing mini grows and im downsizing everything atm.

My newest box is only 0.144m2 and only 0.6m tall.

Im using 4 "old" leds in that project.

2x Nichia NSCWJ216A sm503/G4050-G4850/R8000
2x Vero29 5000k
and added
2x new cree 3590 36v cb.

They are running at a mw-hlg120-c500a
dimmed to 250mA.

I dont find much info about that old Nichia LED.
Does someone has them added to their sheets ?
Im looking for their stats like effency/PAR at 250mA.
(calculating,if co2 addition is needed)


PS: Sry for my poor english
Click to expand...
Bonjour...hola!
Did you already have the cxb?
Why cb and not cd for the same price?
Forget the nichia and run the V29 and cxb(cd!)...you will get better gpw (1.2/1.4!).but it is a lot of w for a small area!
Have a great day ★
 
E

elninonino

Member
ttystikk said:
If your room is sealed, with no air in or out then you would do well with CO² supplementation. If your space is ventilated it will be a waste.
Click to expand...
I would add co2 to the room where the box stands.
The box doesnt transfer the air to the outside.
It just filter it from the box and release it back to the room.
The room was flashed with new air.

I will not add too much co2.
I am aiming for a constant ppm of 1000 at the room.

I need to find a good co2 sensor for my arduino.

littlejacob said:
Bonjour...hola!
Did you already have the cxb?
Why cb and not cd for the same price?
Forget the nichia and run the V29 and cxb(cd!)...you will get better gpw (1.2/1.4!).but it is a lot of w for a small area!
Have a great day ★
Click to expand...
buongiorno,

yes i got them.
Is a cd bin for 3000k available.
The pdf doesnt say so.
Or do you mean instead of 3000k cb the 3500k cd ?

1.2g/W is a new goal i wanna archieve in the future.I dont grow high yielding strains.i prefer small genetics.
But not my first goal.
But im aiming mainly for a better g/kWh,better taste and smell.

i have a reduced consum so one harvest let me 'survive' one grow period.
 
Last edited:
SupraSPL

SupraSPL

Well-Known Member
littlejacob said:
Bonjour
So to be clear a cxb 3590 @1400mA is 56%...ok What is 100% and which diode is using as scale? Because we compare each cob/diodes/cfl/t5/mh/hps to it!
Click to expand...
A 100% efficient green LED would emit 683 lumens/W. A 100% efficient 3500K LED would emit 324 lumens/W. HPS would be ~380lumens/W depending on the bulb. They would all be emitting 1 PAR W/W, but a different photon count for each.

Looking at it in terms of photon count from 400 to 700nm, a 100% efficient 3000K LED would emit about 4.66 umol/s/W. A 100% efficient HPS would emit about 4.66umol/s/W.

Interestingly, a 100% efficient white LED would put down more PPFD than a 100% efficient HPS, because of the reflector losses the HPS deals with. No matter how good an HPS reflector is made, it can never be made as efficient as an LED reflector/lens can be. But it is a non issue, because HID is nearly maxed out in terms of efficiency @ ~40% while white LED is climbing near 70%.
 
littlejacob

littlejacob

Well-Known Member
Bonjour
I thought it was a stupid question (it is!)
But you were able to find a smart answer...are half human-half cob...!
Cobman...you should change your avatar and called you COBMAN!
I always enjoy your posts mon ami...you realy deserve Champagne magnum!(1for you, 1 for Realstyle, 1 for sds, 1for Frenchycannoli,and the 2 last I will see...lol...soon!)
Have a great day ★
 
ttystikk

ttystikk

Well-Known Member
littlejacob said:
Bonjour
I thought it was a stupid question (it is!)
But you were able to find a smart answer...are half human-half cob...!
Cobman...you should change your avatar and called you COBMAN!
I always enjoy your posts mon ami...you realy deserve Champagne magnum!(1for you, 1 for Realstyle, 1 for sds, 1for Frenchycannoli,and the 2 last I will see...lol...soon!)
Have a great day ★
Click to expand...
Save one for me, Mon ami!
 
You must log in or register to reply here.
Top