COB efficiency Spreadsheets

wietefras

wietefras

Well-Known Member
I don't mock measuring PPFD. I'm saying that if you want an estimated light distribution pattern for your grow application of the light, you have it tested in such an environment. Not in an environment that's completely different to what you are ultimately using it in.

It"s like testing winter tires in a desert and conclude they don't work.

So you don't get a light distribution pattern in a black hole, you test it in a tent which replicates the actual use of the light. So put it in a proper grow tent.

I posted an actual PPFD chart for the 1000W Gavita Pro in a grow tent. 800umol/s/m2 with very high uniformity.

THAT is what you need to replace with leds, because that's what people get when they use it.
 
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SaltyNuts

SaltyNuts

Well-Known Member
ok, yes the end result you want is the bright even light. The point of the black box is it's a way to measure the direct light from the fixture. The blackout box is for testing a point source. It's a research and development thing. LED emitters are highly directional in light output. An HPS bulb casts light 360. The reflective interior of a tent is kind of like an extension of the light fixture in either case. You can test the emitter, the bulb, the fixture. There's nothing wrong with your DE in a tent data, it's just not a controversy. It's apples and oranges.
 
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JorgeGonzales

JorgeGonzales

Well-Known Member
wietefras said:
I don't mock measuring PPFD. I'm saying that if you want an estimated light distribution pattern for your grow application of the light, you have it tested in such an environment. Not in an environment that's completely different to what you are testing it in.

It"s like testing winter tires in a desert and conclude they don't work.

So you don't get a light distribution pattern in a black hole, you test it in a tent which replicates the actual use of the light. So put it in a proper grow tent.

I posted an actual PPFD chart for the 1000W Gavita Pro in a grow tent. 800umol/s/m2 with very high uniformity.

THAT is what you need to replace with leds, because that's what people get when they use it.
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Which tent? How wide? How long? How tall? Reflective material? Mylar, panda, barium sulfate paint?
 
wietefras

wietefras

Well-Known Member
You are just making my point that PPFD matrices are useless for comparing lights. You use PPF for that.

If you want to see light distribution you need a PPFD matrix to something which is close to your own situation. A room with black walls is the furthest from actual use as you can get.

I really don't understand what the debate is needed for. HPS growers get 700 to 900umol/s/m2 from their lights. What's the point of presenting measurements in something no one uses and then pretend HPS gives you 200 to 400umol/s/m2? Why not just stick to actually correct figures?
 
SaltyNuts

SaltyNuts

Well-Known Member
wietefras said:
You are just making my point that PPFD matrices are useless for comparing lights. You use PPF for that.

If you want to see light distribution you need a PPFD matrix to something which is close to your own situation. A room with black walls is the furthest from actual use as you can get.

I really don't understand what the debate is needed for. HPS growers get 700 to 900umol/s/m2 from their lights. What's the point of presenting measurements in something no one uses and then pretend HPS gives you 200 to 400umol/s/m2? Why not just stick to actually correct figures?
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I don't know if I understand what this debate is about. But that won't stop me. I think it's safe to say that the design of the interior space is important for maxing efficiency. HPS casts 360 so a reflective interior makes a big difference. I'm assuming there's generally less usable reflected light from an led setup in a similar reflective interior space. Creating a spread output is desired. I'm curious too, what led setup would simulate a DE HPS in brightness. As far as the light measurement data that gets thrown around, I wonder about the accuracy of all that.
 
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churchhaze

Well-Known Member
ttystikk said:
Because he's having heat issues and his other options are all hot HID of one sort or another. His plants are doing fine considering the lack of HVAC and attention.
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He was having heat issues so you have give a lamp with lower efficiency than HPS? Did you ask @BobCajun for help with that decision or what? (he says HPS generates too much heat to even be useful so his solution is CFL)
 
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PurpleBuz

Well-Known Member
wietefras said:
The question was what number and type of COBs it would take to replace an HPS.

You would then either take the PPF of the HPS fixture (not just the bulb) or calculate the PPF from the average PPFD you are aiming for over the grow area.

A black wall PPFD matrix is not the answer.
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that's true, but the black wall matrix gives us a much better picture of the footprint of the light and eliminating environment variables that would confuse the issue.
 
BM9AGS

BM9AGS

Well-Known Member
wietefras said:
I don't mock measuring PPFD. I'm saying that if you want an estimated light distribution pattern for your grow application of the light, you have it tested in such an environment. Not in an environment that's completely different to what you are ultimately using it in.

It"s like testing winter tires in a desert and conclude they don't work.

So you don't get a light distribution pattern in a black hole, you test it in a tent which replicates the actual use of the light. So put it in a proper grow tent.

I posted an actual PPFD chart for the 1000W Gavita Pro in a grow tent. 800umol/s/m2 with very high uniformity.

THAT is what you need to replace with leds, because that's what people get when they use it.
Click to expand...
But the gavita pro pulls 1240w. Also the ppfd chart used a reflector that isn't in production.
 
wietefras

wietefras

Well-Known Member
It pulls 1210W when boosted including driver losses. We don't include driver losses for leds either though and the efficiency of those is similar.

That PPFD matrix was for the light running at 1000W. When boosted you get over 900umol/s/m2 average.
 
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HydrOGdeluxe

Member
First thing I missed in Malocan's data are reflective walls so I have to agree with wietfras.

Either use a sphere, measure the entire footprint the light produces, or use reflective walls. The last one is clearly most practical for us and is still to see how much light can be delivered to the canopy, in the common situation where the canopy surface is smaller than the footprint of the light.

Using reflective sides makes it more doable to compare different mfg, with different hoods and footprint size on the same footprint with the same reflective walls. Whether those walls reflect 90 or 80% doesn't matter. With black walls it's more skewed because you have no idea how much light falls outside the footprint and could normally still reach the canopy. That would be more about testing the reflector hood, to see how well it bundles the light, than testing the amount of light than can be used for growing plants.
 
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PurpleBuz

Well-Known Member
wietefras said:
And whats the point of this "footprint" in the real world?
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It tells us what light actually hits the canopy in a large open grow space or in a greenhouse and its distribution pattern. Based on that one can determine needed overlap coverage. Following that one can estimate how much light can be recovered with side reflection.
 
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PurpleBuz

Well-Known Member
HydrOGdeluxe said:
First thing I missed in Malocan's data are reflective walls so I have to agree with wietfras.

Either use a sphere, measure the entire footprint the light produces, or use reflective walls. The last one is clearly most practical for us and is still to see how much light can be delivered to the canopy, in the common situation where the canopy surface is smaller than the footprint of the light.

Using reflective sides makes it more doable to compare different mfg, with different hoods and footprint size on the same footprint with the same reflective walls. Whether those walls reflect 90 or 80% doesn't matter. With black walls it's more skewed because you have no idea how much light falls outside the footprint and could normally still reach the canopy. That would be more about testing the reflector hood, to see how well it bundles the light, than testing the amount of light than can be used for growing plants.
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if you don't use a sphere you can't standardize and compare the data. If you use reflective sides your testing the reflective sides, the reflector hood as much as you are testing the output of the light .... WAY Too many variables.
 
OneHitDone

OneHitDone

Well-Known Member
A lot of growers with larger rooms don't have a reflective wall right up against the fixture so tent #'s are useless in that situation.

On the issue of driver efficiency - When a COB data sheet says 160lm/w etc, that is referring to the wattage being applied to the cob and has nothing to do with system lm/w which would include driver losses etc?
When something such as a home use screw in led bulb states the lm/w I would assume that is corrected for the draw from the wall. Point being, maybe some of these cob's aren't as efficient as it would first appear?
 
JorgeGonzales

JorgeGonzales

Well-Known Member
OneHitDone said:
A lot of growers with larger rooms don't have a reflective wall right up against the fixture so tent #'s are useless in that situation.

On the issue of driver efficiency - When a COB data sheet says 160lm/w etc, that is referring to the wattage being applied to the cob and has nothing to do with system lm/w which would include driver losses etc?
When something such as a home use screw in led bulb states the lm/w I would assume that is corrected for the draw from the wall. Point being, maybe some of these cob's aren't as efficient as it would first appear?
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Correct on all counts my friend.
 
SaltyNuts

SaltyNuts

Well-Known Member
The tent will have more total light because of reflections, period. No one disagrees on that. The black box is for precise measurement. There's no conflict.

Hang cob fixture in a tent and measure PPF. Hang a DE in there, measure PPF. Compare various heights above canopy, compare results at cobs and DE driven at various power levels. Better yet, do a side-by-side run and compare results and publish them here for everyone to pick apart. Watch your life fall to pieces in sleepless nights and anxiety. Do it again.
 
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HydrOGdeluxe

Member
PurpleBuz said:
if you don't use a sphere you can't standardize and compare the data. If you use reflective sides your testing the reflective sides as much as you are testing the light .... Too many variables.
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I disagree with all of that and you are clearly missing my points. In your reply to wietefras you assume they always measure the entire footprint the light produces and not a fixed 4x4' or so. The footprint they measure would have to be variable to see the overlap and reflection potential. It's why I asked Malocan to use either reflective walls or also measure the 8x8 edge around the 7x7 squares he measures. Either will give a better idea of how much light can be delivered to the canopy. Especially when comparing hps to led but also different lenses.
 
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PurpleBuz

Well-Known Member
HydrOGdeluxe said:
I disagree with all of that and you are clearly missing my points. In your reply to wietefras you assume they always measure the entire footprint the light produces and not a fixed 4x4' or so. The footprint they measure would have to be variable to see the overlap and reflection potential. It's why I asked Malocan to use either reflective walls or also measure the 8x8 edge around the 7x7 squares he measures. Either will give a better idea of how much light can be delivered to the canopy. Especially when comparing hps to led but also different lenses.
Click to expand...
are you testing the tent or the light or the reflector ?
 
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