COB Spacing and Power To COB Talk

With COB tech taking over the LED horticulture world and so many companies popping up and making fixtures.The big question always arises? watts per square foot? Distance from canopy for coverage? And the all important SPACING!? The optic I use is 1st generation cob! There are flaws but the unit is sound and not skipping a beat. The 2nd generation will for sure have the bugs worked out! The power to the chip is big plus for the optic. Spacing on the other hand is off! At this moment my opinion for the perfect cob fixture would be 90 watts power to each chip spaced 16inches apart 12 to 16 inches from canopy. Whats your opinion? I am sure there will be many.

What 'flaws' do you speak of?

COB spacing is the only fault in my opinion. 16 inches spaced center squared maybe 18? The 200watt box needs to be 7x18 or so the 360 box should be 18x18 square! I am nit picking because I believe optic units are best available at the moment! but still 1st gen flawed! They are ahead the game though! EVERYONE is based from them! Just my opinion though!

I think we should try to move away from Watts per square foot, I know people like using it because it is a simple way to quantify the amount of power being output, and everyone can do the calculation, but realistically it is essentially meaningless because the watts need to be par watts. I think it would be much better to move towards using PAR/Watts Per Square foot, I think supra had posted some information on how to do this conversion on another thread (Maybe me saying this will prompt him to post it here again). If I recall correctly Supra was also saying that a good estimate of ideal light was 25-30 PAR/Watts Per Square foot.

coolbreez1 said:

I think we should try to move away from Watts per square foot, I know people like using it because it is a simple way to quantify the amount of power being output, and everyone can do the calculation, but realistically it is essentially meaningless because the watts need to be par watts. I think it would be much better to move towards using PAR/Watts Per Square foot, I think supra had posted some information on how to do this conversion on another thread (Maybe me saying this will prompt him to post it here again). If I recall correctly Supra was also saying that a good estimate of ideal light was 25-30 PAR/Watts Per Square foot.

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Total Dissipation (W) / Area = Watts per square feet/meter

Total Dissipation (W) * Proposed Efficiency (%) = PAR (W)

For example, a fixture may dissipate ~300W (power output from COB(s)) and be ~43% efficient; this translates to ~130 PAR watts. Say this fixture covers a 4' x 2' reflective tent:

PAR (W) / Area (ft.^2) = 16.25 PAR W per square feet

Also, I believe you misread Supra's words - it's 25-30 W per square feet and 10-15 PAR W per square feet when using Vero or Cree COBS, with efficiencies above 40%.

I'll be sure to add PAR W estimates to the HB fixture descriptions, Breez .

Photons output=potential coverage
It's really that simple. And is not a new form of science.

You need 700-1000µmols PPFD/m2 average. So individual points can be higher and lower. But also keep in mind saturation levels starting around 1300µmols and are hard set in the 1500+µmols range.

All the watts and PAR watts talk and figures are just correlated variables to PPFD and PPF. Keyword...VARIABLES.
Photosynthesis is quantum process. And can be quantified with photons, not energy.

Give your area a sufficient amount of photons and stop trying to reinvent the wheel.

AquariusPanta said:

Total Dissipation (W) / Area = Watts per square feet/meter

Total Dissipation (W) * Proposed Efficiency (%) = PAR (W)

For example, a fixture may dissipate ~300W (power output from COB(s)) and be ~43% efficient; this translates to ~130 PAR watts. Say this fixture covers a 4' x 2' reflective tent:

PAR (W) / Area (ft.^2) = 16.25 PAR W per square feet

Also, I believe you misread Supra's words - it's 25-30 W per square feet and 10-15 PAR W per square feet when using Vero or Cree COBS, with efficiencies above 40%.

I'll be sure to add PAR W estimates to the HB fixture descriptions, Breez .

Click to expand...

This would all be assuming that we are using the right kinds of LED COBs in which all of the light being output falls into the PAR interval.

GG: The only point I am trying to make here is that if you are having photons being output that are outside of the PAR interval that they are not going to be parenthetically active and they should not be included in the calculation. Some of the HPS lights that are not designed well have massive spikes in output at certain wavelengths, to the degree that the plant is not going to be able to utilize all of the photons. In which case these photons should not be counted towards your over all watts per square foot. I am not trying to be reinvent anything, just aiming for accuracy.

JimmyIndica said:

COB spacing is the only fault in my opinion. 16 inches spaced center squared maybe 18? The 200watt box needs to be 7x18 or so the 360 box should be 18x18 square! I am nit picking because I believe optic units are best available at the moment! but still 1st gen flawed! They are ahead the game though! EVERYONE is based from them! Just my opinion though!

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If I'm going to plug optic, they GOTTA step up the build quality. But I was in the 500 watt model 20 inches center line square might kill it in the 4x4

Sent from my SM-G900V using Rollitup mobile app

JimmyIndica said:

With COB tech taking over the LED horticulture world and so many companies popping up and making fixtures.The big question always arises? watts per square foot? Distance from canopy for coverage? And the all important SPACING!? The optic I use is 1st generation cob! There are flaws but the unit is sound and not skipping a beat. The 2nd generation will for sure have the bugs worked out! The power to the chip is big plus for the optic. Spacing on the other hand is off! At this moment my opinion for the perfect cob fixture would be 90 watts power to each chip spaced 16inches apart 12 to 16 inches from canopy. Whats your opinion? I am sure there will be many.

Click to expand...

I think the output per emitter and spacing are dependent so there is no ideal output per emitter, except less output = more emitters, better coverage and lamp can be closer to canopy.

I do agree that spacing is an issue with some lamps not being ideal for tent sized areas. Hang em high and hope for the best. I also have issue with cob lamps being ran above nominal current.

canopy penetration with an underpowered cob? Why not run them on high so to speak! and replace the chips 6 months-1year for something better?

coolbreez1 said:

GG: The only point I am trying to make here is that if you are having photons being output that are outside of the PAR interval that they are not going to be parenthetically active and they should not be included in the calculation. Some of the HPS lights that are not designed well have massive spikes in output at certain wavelengths, to the degree that the plant is not going to be able to utilize all of the photons. In which case these photons should not be counted towards your over all watts per square foot. I am not trying to be reinvent anything, just aiming for accuracy.

Click to expand...

I just now realized what you're argument was and it's brilliant; I would coin your description 'photon intake efficiency'. O yeah baby, we're adding chrome spokes to these rims!

PAR W per square feet is a great way to determine how much output we need in a given space but at the same time, focusing intensity in the middle of the grow space is going to be considered more inefficient than if one were to reduce intensity in the middle and rather instead spread it across the entire grow space as diminishing returns eventually take place in the middle of the space, while the surrounding area canopy shouts "give me more!". The same logic runs along with even-height canopies; the goal is to evenly distribute light so no one main cola can block a majority of light from the rest of the plant colas.

I'd like to hear what others have to say, as I find this topic extremely intriguing

coolbreez1 said:

This would all be assuming that we are using the right kinds of LED COBs in which all of the light being output falls into the PAR interval.

GG: The only point I am trying to make here is that if you are having photons being output that are outside of the PAR interval that they are not going to be parenthetically active and they should not be included in the calculation. Some of the HPS lights that are not designed well have massive spikes in output at certain wavelengths, to the degree that the plant is not going to be able to utilize all of the photons. In which case these photons should not be counted towards your over all watts per square foot. I am not trying to be reinvent anything, just aiming for accuracy.

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It wasn't directed at you individually. It is for everyone. In this thread, the cob high thread, and the 1K replacement thread all have had the same run around of wrong information about what is coverage. And I am sick of seeing it.
PPF is all the photons in the PAR range and is what is used in botany. Again...photons. PAR ones like I specified with PPF and PPFD. Some call PAR 400-700...that's wrong by definition. PAR light is any nm of light that can make photosynthesis happen. Even if only 1% or 2% worth. Any photon from 315nm-780nm can drive photosynthesis.

I did not make up photons importance. I am not trying to sell an idea for any alternative benefit. It is just the correct way to measure and report on lighting pertaining to growing. Ad I would like to see it actually used. This community has come very far over the last 2 years, with more of the population understanding at a deeper level than ever before. So use the right level. It is literally 1 more step than what you do to get PAR watts. You guys can do it, I believe in your guys...most of you.

Many people will jump down an HPS guys throat for an uneducated statement about light. This is no difference, except I am not jumping down anyones throat. Only continuing the same statement I have been making on here since 2011. It all comes down to the photons(PAR photons for those that want to pick apart every word and punctuation, or autocoreect...I see all AP). I have been the biggest proponent of quantum measurements and readings since before COB's were a concept in manufactures minds and that is because where it comes form has nothing to do with what it will result in...I.E. hps, led, floro, cmh photons are all the same in physical nature...it all comes down to quantum measurements.

What I am interested in and would like to see more of are PAR percentages broken down by nm.

coolbreez1 said:

This would all be assuming that we are using the right kinds of LED COBs in which all of the light being output falls into the PAR interval.

GG: The only point I am trying to make here is that if you are having photons being output that are outside of the PAR interval that they are not going to be parenthetically active and they should not be included in the calculation.

Click to expand...

PPFD = Photosynthetic Photon Flux Density

Photosynthetically = PAR, => PPFD take into account wether your photon is, or isn't good for photosynthesis ...

puffenuff said:

What I am interested in and would like to see more of are PAR percentages broken down by nm.

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That's what SPD curves are for. Of course it would be great to have a more precise source of data, but SPD curves give already plenty of good enough information ...

Yes, I want precise numbers. I wish more lights were analyzed with a spectroradiometer

I agree with what you are saying GG, I had forgotten the definition of PPFD. I am in agreement that PPFD would be the preferred term, over par watts per square foot.

The PAR interval does have an upper boundary of how many photons in a particular spectrum can be effectively utilized. I don't believe this to be a big issue with most of the Cree and Bridgelux COBs because the have nice smooth curves of photon distribution, so in most cases this is a none issue.

However, I think, It is worth noting within the context of PPFD that if you were I take a Vero 29 and just output all the light at 680 nm, or one isolated spectrum it will not be as effective as having it all distributed such as in the 4000k light. As AquariusPinta coins the term, photon intake efficiency, I think this would be the level after PPFD, and as GG points out different protons have different levels of effectiveness within the PPFD spectra. I don't claim to have any great understanding of all of these variables, but I would suspect one has to consider all of the relative values of all the spectral output the plant is being exposed to; such that no spectrum can truly be measured in isolation, and they can only only be seen within the context of all of them. It makes my head hurt just thinking about it.

I think it is likely even more complicated then that given that it has been shown that solar panel efficiency can be effected by the ambient sound aka music.

AquariusPanta said:

I just now realized what you're argument was and it's brilliant; I would coin your description 'photon intake efficiency'. O yeah baby, we're adding chrome spokes to these rims!

PAR W per square feet is a great way to determine how much output we need in a given space but at the same time, focusing intensity in the middle of the grow space is going to be considered more inefficient than if one were to reduce intensity in the middle and rather instead spread it across the entire grow space as diminishing returns eventually take place in the middle of the space, while the surrounding area canopy shouts "give me more!". The same logic runs along with even-height canopies; the goal is to evenly distribute light so no one main cola can block a majority of light from the rest of the plant colas.

I'd like to hear what others have to say, as I find this topic extremely intriguing

Click to expand...

You are right on the money AquariusPanta!
I also like to do something I don't see utilized too much - rather than tie or stake branches upright I like to spread them out and move the plants around regularly so light is has a chance to make it to all the bud sites. By doing this and weeding out anything that is too small early on I have almost no undesirable popcorn fluff come harvest

coolbreez1 said:

I agree with what you are saying GG, I had forgotten the definition of PPFD. I am in agreement that PPFD would be the preferred term, over par watts per square foot.

The PAR interval does have an upper boundary of how many photons in a particular spectrum can be effectively utilized. I don't believe this to be a big issue with most of the Cree and Bridgelux COBs because the have nice smooth curves of photon distribution, so in most cases this is a none issue.

However, I think, It is worth noting within the context of PPFD that if you were I take a Vero 29 and just output all the light at 680 nm, or one isolated spectrum it will not be as effective as having it all distributed such as in the 4000k light. As AquariusPinta coins the term, photon intake efficiency, I think this would be the level after PPFD, and as GG points out different protons have different levels of effectiveness within the PPFD spectra. I don't claim to have any great understanding of all of these variables, but I would suspect one has to consider all of the relative values of all the spectral output the plant is being exposed to; such that no spectrum can truly be measured in isolation, and they can only only be seen within the context of all of them. It makes my head hurt just thinking about it.

I think it is likely even more complicated then that given that it has been shown that solar panel efficiency can be effected by the ambient sound aka music.

Click to expand...

YPF...yield photon flux
EDIT:
For you to dig deeper into where you are heading...
https://www.rollitup.org/t/cree-cxa-3000k-80cri-spectrum-analysis.832666/

AquariusPanta said:

PAR W per square feet is a great way to determine how much output we need in a given space but at the same time, focusing intensity in the middle of the grow space is going to be considered more inefficient than if one were to reduce intensity in the middle and rather instead spread it across the entire grow space as diminishing returns eventually take place in the middle of the space, while the surrounding area canopy shouts "give me more!". The same logic runs along with even-height canopies; the goal is to evenly distribute light so no one main cola can block a majority of light from the rest of the plant colas.

Click to expand...

I know these guys lights are a little on the janky side but this demonstrated the spreading of a lower intensity light very well as this was discussing.


I am really digging the idea of a cob fixture the size of the grow space with the cobs spread evenly throughout. Or multiple small panels that allow you to achieve a similar spacing goal. (new A51?)

Cramming all the cobs towards the center on one heatsink just sees too close to the same as an hid in a central reflector to me

P.S. I wish someone had an accurate spectroradiometer grid for the IG 420/pontoon combo

OneHitDone said:

I know these guys lights are a little on the janky side but this demonstrated the spreading of a lower intensity light very well as this was discussing.

I am really digging the idea of a cob fixture the size of the grow space with the cobs spread evenly throughout. Or multiple small panels that allow you to achieve a similar spacing goal. (new A51?)

Cramming all the cobs towards the center on one heatsink just sees too close to the same as an hid in a central reflector to me

P.S. I wish someone had an accurate spectroradiometer grid for the IG 420/pontoon combo

Click to expand...

That was a joke of a measurement video. I like how they measure along the 48" side of a 48"x15" fixture.


Post 209 are some of my indagro measurements...enough to get a solid idea of what is going on.
https://www.rollitup.org/t/greengenes-apache-at600-garden-blackberry-kush.763210/page-11#post-10177696