COB Spacing and Power To COB Talk

[PurpleBuz]

Wanna know what would really simplify things? Take the watts dissipated and multiply it by the efficiency on the efficiency chart. Take that number and divide it by the total area of your grow. Done. Who are you trying to sell lamps to anyway, Einstein? Also, what crazy SPD are you planning on using that doesn't have a very similar QER to cxa 3000k 80cri? Are you going boost the red and cut the blue as if that's a ticket to few free extra umol/s without increasing W? Just gotta turn a few knobs...

And that's my issue with the "it's not watts, it's umol/s" line of thinking. Photosynthesis is a process of transferring light energy to chemical energy. It takes energy to create the sugars, and that's why the nutritional value is not measured in the umol/s worth of sugars produced.

that doesn't simplify anything, I can measure umol/s at the canopy and its more closely related to the rate of photosynthesis than watts, horse power, current, voltage or wavelengths. If you really want a better measurement try measuring O2 production at different points around the canopy. Using O2 production eliminates almost everything except non-photosynthesis related effects of light on plant physiology.

LOL I haven't talked like that since I graduated

 

[Greengenes707]

Wanna know what would really simplify things? Take the watts dissipated and multiply it by the efficiency on the efficiency chart. Take that number and divide it by the total area of your grow. Done. Who are you trying to sell lamps to anyway, Einstein? Also, what crazy SPD are you planning on using that doesn't have a very similar QER to cxa 3000k 80cri? Are you going boost the red and cut the blue as if that's a ticket to few free extra umol/s without increasing W? Just gotta turn a few knobs...

And that's my issue with the "it's not watts, it's umol/s" line of thinking. Photosynthesis is a process of transferring light energy to chemical energy. It takes energy to create the sugars, and that's why the nutritional value is not measured in the umol/s worth of sugars produced.

Cause every avg joe knows what PAR watts is right. Let alone how to work with it. µmols is more standard and understandable.
How do plants take in the energy eh? Photons.
I just ate a burger...but you would say I ate protein(and some other stuff).

I have never said PAR watts are worthless or the math behind them is wrong. But they are the wrong unit for light and plant growth.

 

[churchhaze]

Cause every avg joe knows what PAR watts is right. Let alone how to work with it. µmols is more standard and understandable.
How do plants take in the energy eh? Photons.
I just ate a burger...but you would say I ate protein(and some other stuff).

I have never said PAR watts are worthless or the math behind them is wrong. But they are the wrong unit for light and plant growth.

When you eat a hamburger, you generally think of it in terms of calories, which is a unit of energy. The reality is energy is a concept and that what's actually happening can be quantifiable in terms of chemical bonds. Each bond has a discrete amount of energy associated with it, similar to how photons have discrete amounts of energy. Using calories is a way to abstract all that's going on. Your hamburger argument is actually helping me to make my point that using units of energy and power is more intuitive for our purposes than quantity of photons. It would be absurd to measure the amount of energy a hamburger provides by counting the bonds being broken up.

 

[Greengenes707]

When you eat a hamburger, you generally think of it in terms of calories, which is a unit of energy. The reality is energy is a concept and that what's actually happening can be quantifiable in terms of chemical bonds. Each bond has a discrete amount of energy associated with it, similar to how photons have discrete amounts of energy. Using calories is a way to abstract all that's going on. Your hamburger argument is actually helping me to make my point that using units of energy and power is more intuitive for our purposes than quantity of photons. It would be absurd to measure the amount of energy a hamburger provides by counting the bonds being broken up.

I'm not so sure...I(the plant) ate a burger(the photon) that was made of things that have a calorific value(energy).

EDIT
And yes it is absurd to count that much...which is why we actually use µmols. Simplified.

 

[PurpleBuz]

When you eat a hamburger, you generally think of it in terms of calories, which is a unit of energy. The reality is energy is a concept and that what's actually happening can be quantifiable in terms of chemical bonds. Each bond has a discrete amount of energy associated with it, similar to how photons have discrete amounts of energy. Using calories is a way to abstract all that's going on. Your hamburger argument is actually helping me to make my point that using units of energy and power is more intuitive for our purposes than quantity of photons. It would be absurd to measure the amount of energy a hamburger provides by counting the bonds being broken up.

what happens if your a vegan and eat vege burgers ?

 

[churchhaze]

I'm not so sure...I(the plant) ate a burger(the photon) that was made of things that have a calorific value(energy).

EDIT
And yes it is absurd to count that much...which is why we actually use µmols. Simplified.

I still want to know what SPD you plan on using to get your umol/s up without also increasing your PAR W. The whole argument is moot point.

Edit: Lets say you start with a lamp with an SPD perfectly resembling the McCree curve? How would you increase umol/s without increasing PAR W? It wouldn't be McCree anymore. Yes, it's an edge case that's only possible theoretically...

 

[Greengenes707]

I still want to know what SPD you plan on using to get your umol/s up without also increasing your PAR W. The whole argument is moot point.

Edit: Lets say you start with a lamp with an SPD perfectly resembling the McCree curve? How would you increase umol/s without increasing PAR W? It wouldn't be McCree anymore. Yes, it's an edge case that's only possible theoretically...

Where and when did I ever say I am or could do that.

Like I said...they are similar, and can be related. But one is correct for referencing plant growth and one isn't. I am not the one who determined or decided this. It was actually the plants, then explained by humans.

 

[bicit]

what happens if your a vegan and eat vege burgers ?

Alpha particles.

 

[salmonetin]

...if you are led lamp seller... or frecuently test diferent leds... better go with par meter ...for measures in situ... ...verificate led bins... etc...

...if you are a poor man without par meter you can go with par w and other calcs to obtain ppfd and help on design calcs...not substitute a real measurment... but give us on aproximate value to help on calcs for disegns...

...par w = radiant flux too... from mi pov ...maybe im wrong...

PD... im talk with Pos... he prefer see me talkin ...not in the silence mode...

...Wilson...alone in the island... resistance mode activated...welcome to the resistance mode...



saludos

 

[bicit]

Working everything out in umols/m^2 would indeed be more accurate. Better for scientific discussions especially.

Quick and dirty closet growers can get by with par/w and skip to the good part. Getting the plant to grow

For measuring uniformity a cheap lux meter is sufficient. No need to get a expensive special purpose meter for this.

Measuring actual photon density and spectral distribution at the canopy isn't really necessary for the average indoor Gardner. Most don't give it a second thought. We really are a bit of an oddity on this forum.

 

[ttystikk]

Thinking about the action different sources have on the plants growth got me to thinking about what happens to all that energy they DON'T USE? Some goes into transpiration, but much ends up as heat in the room. This explains why my HPS thouies never did that much better than other lights, but required a lot more cooling. Here is an aspect of the watts/ft², umol, PAR, PPfd discussion that is underrepresented and it absolutely does have a lot to do with overall efficiency. In our conversation about lighting, let's not forget the unseen companion to inefficiency- heat.

For what it's worth, I'm a big fan of using PPfd to help me choose light sources and Kelvin numbers.

Then, I'm a big fan of even spacing with lots of well distributed light sources, as that gives nearly the same effects as light movers in terms of eliminating shade. I'd like to aim for 20 watts of PPfd per square foot...

Finally, the equipment itself needs to also be highly efficient, as that pays dividends both in photons and reduced cooling needs.

I realise this won't be cheap up front. But if it is substantially more cost effective to run than other options, then eventually it pays for itself, sooner or later, no matter what.

 

[SupraSPL]

I used to think that a 1000 Hortilux HPS in a 4X4 was a good benchmark to aim at:
1000W * 36% efficiency = 360 PAR W.
360 * .8 reflector losses = 288 * .95 wall losses/scatter = 273.6 PAR W
273.6 / 16 ft²= 17 PAR W/ft²
17 X 4.66umol/s * 10.7 = 847 PPFD averaged when brand new (960 for 1000W DE)

Growershouse tested the 1000W Hortilux in a 4X4 with a cooled hood and it looks most efficient at 24" distance from canopy. Uniformity is poor and I figure it at about 550 PPFD averaged. When you pull the hood back you get better uniformity but average PPFD drops way off. Also only ~20 CRi, peaky lopsided SPD curve.


This a is a bare 1000W HPS DE tested last December, 30-40 CRi and a decent improvement in intensity 615 PPFD averaged, but still poor uniformity.



Anyway, now we are building COB lamps with 1000 PPFD averaged, 80 CRi and improved uniformity thanks to COB spacing. We should see some really nice improvements over the HPS gardens. I know I won't be switching back

 

[Sxott]

Thanks. The 10 cob cxb3070s are using 2x hlg-185h-c1050b and the 8 cob cxb3590 is using 2x hlg-185h-c1400b.

 

[Budzbuddha]

IMHO on cob spacing is to start with how many cobs your using to achieve the ppfd you want for your canopy and then space them out equally.

I like to divide my grow area in equal segments. The amount of segments its divided by is equal to the amount of COBs I am using and then center that cob over each segment.

For example Im using 8x cxb3590 in a light that is covering a 2'x4' space. The cobs will be spaced 12" apart. (1 cob centered over each of the 8 square ft of the growing area)

I have about 1300 ppfd that is equally distributed on my canopy when running full power.

Another light I have built is close to the same ppfd is a 10 cxb3070 covering a different 2x4 area. I cant divide a 2x4 area in 10 square shaped segments so... Each cob is centerd over a 9.6"x12" area. So I have 2 rows of 5 cobs that are a 12" apart but only 9.6" apart along the same row.

I feel this is the best way to get an even light intensity across the canopy. If I were going to try this same build in a 2ft square case, the light would be much stronger in the center than on the edges of the tent.

That 10 COB is nice , what is the spectrum choices ?
Have you thought about posting a buildup for that one ?
I have a similar tent size and am looking for a COB build for it.

 

[Budzbuddha]

Thanks. The 10 cob cxb3070s are using 2x hlg-185h-c1050b and the 8 cob cxb3590 is using 2x hlg-185h-c1400b.

What about radiant heat from passive sinks ? Is there any modified exhaust requirements ?

 

[Scotch089]

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.

Haven't even read the rest of the thread... but, my man! Fuckin ON IT

 

[Scotch089]

Assuming the same spd...
More energy=more photons
More photons=more energy
Half full or half empty.
That doesn't make it correct for what we are talking about. Or a way to compare any light because it works with the same SPD...so does lumens. Is it close, and can be related...sure...but again, not correct. Your issue is with plant physiology which I find hard to over turn.

And also doesn't help when it comes to canopy intensity. PAR watts, and avg PPFD will not tell you instantaneous PPFD...which is not the same as avg PPFD. I can take sufficient PAR watts and hang it too high it will not perform. Then also the other side of it... I can take insufficient PAR watts but create acceptable canopy intensity for better growth than sufficient but not ideal in use. All coming back to the plants direct relationship with photons.

Plants require an avg PPFD of 700-1000µmols. But can handle instantaneous intensities of 1500µmols.

I'm getting a headache nodding so fuckin much.... YOU should start your own forum g.

 

[Sxott]

What about radiant heat from passive sinks ? Is there any modified exhaust requirements ?

I dont run them passive. However I did accidentally forget to turn the fans on in a 24x48x42 cabinet with it on high for a few hours. Doors closed and the cabinet hit 95° and the heatsinks were warm to the touch. There were 5x 80mm fan holes (fans not on) for the heat to escape on its own.

Now the lights are in 2x4x6 ft tent. Fans on top of heat sink and a little 4" duct booster exhausting out the top of tent. Temp only goes up a few degrees above ambient and the heatsinks are cool to the touch.

Im installing a 12v 5amp power switching supply on all my lights now so I can use a single timed plug for light, cooling, air moving and, exhausting. ( trading duct booster out for a pc fan in a piece of pvc pipe. )

 

[salmonetin]

I dont run them passive. However I did accidentally forget to turn the fans on in a 24x48x42 cabinet with it on high for a few hours. Doors closed and the cabinet hit 95° and the heatsinks were warm to the touch. There were 5x 80mm fan holes (fans not on) for the heat to escape on its own.

Now the lights are in 2x4x6 ft tent. Fans on top of heat sink and a little 4" duct booster exhausting out the top of tent. Temp only goes up a few degrees above ambient and the heatsinks are cool to the touch.

Im installing a 12v 5amp power switching supply on all my lights now so I can use a single timed plug for light, cooling, air moving and, exhausting. ( trading duct booster out for a pc fan in a piece of pvc pipe. )

any pics?...

saludos

 

[Rahz]

I don't think the average Joe know what par umol or ppfd is. It would take a large scale advertising campaign to create enough awareness for those figures to be useful to the average Joe.

Take HPS bulb comparisons. You end up with some charts with comparison numbers. Bigger numbers = better. The idea of what the numbers mean is lost on most, and to be fair most growers have only a passing interest in the science behind the readouts and really just want to know what is best and/or cheapest.

If I end up producing fixtures I will provide ppfd in the suggested area along with output wattage. Why? Because it will cover all my bases and they are the largest numbers