I am a donkey, may you help me understand?
Aren't 500µMoles in both cases? different heights but same result at canopy level, 1st fixture is less powerful but closer to canopy, second one is more powerful but farther away from plants. No?
LED Panel F-Series GEN 3 or Bridgelux EB Series Gen 2
- Thread starter overdriver
- Start date
Aren't 500µMoles in both cases? different heights but same result at canopy level, 1st fixture is less powerful but closer to canopy, second one is more powerful but farther away from plants. No?
wietefras
Well-Known Member
Like alesh explained, inverse square does apply to point light sources free to spread their light around. That was however not the case we were discussing.
The argument was about fixture distance to canopy. Which means with multiple light points causing overlap and hung inside reflective walls. By the nature of the application the light is also well within the distance where "ISL" is negated.
The only thing your simulation showed is that indeed "ISL" applies per light point, but at the same time the outcome clearly showed that "ISL" does NOT apply for the combination of those light points. The latter was what the discussion was actually about. So you have effectively proven that you are wrong.
Moreover, even IF you were right that ISL applies to fixture to canopy distance, the amount of light you'd need to be able to hang a light at 40" and still get 500umol/s/m2 at the canopy level is staggering. You'd need 64 times (40/5=8^2=64) the amount of light to start with. So for 500umol/s over a square meter you'd need about 200W from a light at 5", but to hang it at 40" and to then still get the same 500umol/s over that m2 after applying "ISL" you would need a 12800W fixture. Brilliant really.
Whatever you now pretend you made those tables for, they are completely useless when you don't show how much light you need to start with to get the selected light level at the canopy.
Apart from the fact that those tables are completely wrong to begin with since "ISL" does not apply to fixture to canopy distance at all.
There is at least a dozen people trying to get you to understand how wrong you are on just about everything. You can pretend they are all my "boyfriends", but perhaps you should finally try to get over your cognitive dissonance and see that you are indeed the one who is wrong.
You took measurements and it showed a straight line. How on earth can you conclude from this straight line that "ISL" applies just because the intensity decrease on the last two points is "only" 11% different from what "ISL" would show? Again, here is a a chart of YOUR measurements:
You keep jammering on about how ISL only applies from a distance 5 times greater than the light is wide (because of overlap).
So who hangs their light at 10 feet? How can you not understand that when it's less than 10 feet "ISL" does not apply to fixture height?
ISL says that light spreads over an area which grows at a quadratic pace with distance. How can you not understand that if you reflect the light back into a confined area that this does not apply anymore? That then the only loss of light you experience is due to light absorbed by the walls (due to lower than 100% reflectance of the wall material).
This is not about ISL being something that exists in general, but specifically about the distance between the fixture and plant canopy. Just like you measured and like you display in those penetration tables.
It's just staggering how easy it should be to see that you are wrong. Everybody here does, but you.
Last edited:
sureshot138
Well-Known Member
isl is based in single point light (the sun) angles and degrees not good for relating distance. example if our sun is 93000000 miles away and like 1000000 miles wide it could be 10x more or less that and be observed as the same. I think it was said before this benefit only exists in the mind in form of an equation.
overdriver
Member
I'm loving the beef 
btw. I've read that most meanwell HLG driver exceed their max current output by 10-20%. Is this true?
Can it still do this when voltage output is at 100%? So a 200W driver would have 210-220W ?
btw. I've read that most meanwell HLG driver exceed their max current output by 10-20%. Is this true?
Can it still do this when voltage output is at 100%? So a 200W driver would have 210-220W ?
Serva
Well-Known Member
The „A“ version maybe. Otherwise 6-8% (? See datasheet) more power is possible, 20% sounds crazy.I'm loving the beef
btw. I've read that most meanwell HLG driver exceed their max current output by 10-20%. Is this true?
Can it still do this when voltage output is at 100%? So a 200W driver would have 210-220W ?
GrowLightResearch
Well-Known Member
You are just to much. Negated? As in light no longer follows the laws of physics? So you have your own little world with a dead zone where the laws of physics are suspended? Okay. Carry on. I have nothing to contribute to that.
Fig. 4 in the datasheet is luminous flux vs. drive current.
Last edited:
wietefras
Well-Known Member
The light stops spreading when it hits a reflective surface yes. Or do you see any light falling outside of your closed grow room? Perhaps you forgot to put the tent material over the tent poles? That would explain a lot really.
Either way, like I said, laws of physics apply just fine. You just don't understand them.
That we can all agree on.
GrowLightResearch
Well-Known Member
They are the same to the leaves that are located at the level where 500 µMoles of PPFD was measured.
Light spreads out as it travels. As it spreads out the light covers a greater area but there are less photons per square area. Still the same number of photons but spread out more.
As light travels, as the travel distance doubles, it spreads out 4x.
Example:
The light from your grow light travels 12" to the highest leaf in your canopy.
There is another leaf the light hits directly 12" further away from the grow light than the other leaf.
So one leaf is 12" and the other is 24" from the grow light.
Let's say the top most leaf that is 12" from the grow light the PPFD is 1000 µMoles.
The PPFD at the leaf 24" from the grow light will have a PPFD of about 250 µMoles.
Now change the distance so the the top leaf is 36" and the other leaf 48" from the grow light.
Adjust the intensity of the grow light so the the top leaf is again getting 1000 µMoles.
At these distances the PPFD at the leaf 48" from the grow light is 563 µMoles.
At 12" and 24" the 24" leaf got 25% as much light as the 12" leaf.
At 36" and 48" the 48" leaf go 56% as much light as the 36" leaf.
In both cases the difference in distance between the two leaves remained 12".
This does not mean you should hang your grow light 36" from the canopy.
This just illustrates there is a difference in PPFD on the leaves depending on the height of the grow light.
The height of the plant and density of the canopy are factors as well.
GrowLightResearch
Well-Known Member
You do not read very well, I said I do not use reflective walls.
And no it does not stop spreading.
Would you please stop posting stuff no one understands?
haze010
Well-Known Member
Late to the thread but on strip choice why does everyone forget about samsung H series? its just as viable as f series.
I did the 2 foot ones and if youre doing 25 or more the price isnt bad.
https://www.arrow.com/en/products/si-b8v11156hus/samsung-electronics
Under $9 a strip, when i did mine it was closer tho $8 though.
I did the 2 foot ones and if youre doing 25 or more the price isnt bad.
https://www.arrow.com/en/products/si-b8v11156hus/samsung-electronics
Under $9 a strip, when i did mine it was closer tho $8 though.
GrowLightResearch
Well-Known Member
I said a grow light. The light source in my example is a single little very bright grow light. Not a huge fixture like you assume. You need to stop making so many assumptions. You are always wrong.
More assumptions. Sane? You're not, you are psychotic. So what would you know about sane people?
There are growers with very large rooms with no reflective walls.
There is ISL. Overlap just makes it more difficult to calculate. It can be measured just like any other light source.
I also specified the distance from the two leaves without orientation to one another and not by changing the height of a fixture but by changing the distance between the leaves. In an example I can do stuff like that.
And I knew that, my BMW manual says that I should not try to defy the laws of physics. That doesn't stop you. You say laws of physics do not apply all the time. Although I know you are full of shit.
Einstein and Planck got it right. You got it wrong. ISL always applies with any light source at any distance. If the dimensions of a light source are greater than one fifth the distance you just treat it as multiple light sources. Guess what? That actually works.
It was YOUR incorrect assumptions. Stop that! And yes, absolutely, ISL applies to fixture height. Why would it not?
Maybe if you had taken the time to understand what I did you wouldn't recall it in such a convoluted way.
Absolutely not linear. Unless you are so stupid that you take two end points with no values in between and expect to see an inverse relationship like you did with your silly graph.
It's not a guess. Probability estimates how far it gets very accurately. Do the math.
Yes, yes. You are learning. The light from each source continues to spread out. The overlapping light does nothing to the light from the other light source. They work in harmony. Just treat them right. Treat them like they are each their own source. Sum them together. It works!! Really, it works. One thing for sure, overlap does not cancel ISL. It's just a little more complex.
If you would try to understand what I say rather than fight me every inch of the way you'd get this stuff already. That's called ignorance when you ignore me. Quit being so ignorant. Please.
GrowLightResearch
Well-Known Member
Just finished putting this together.
Seven BXEB-L0560Z-30E2000-C-B3
Powered in series by one HLG-240H-C1400B
With the HLG at max:
Wall watts: 220 watts (probably more than 1400mA)
Temperature: 59° C @ Tc2
The Mean Well driver is much hotter than the strips.
I can touch the strips for a few seconds without swearing. Cannot say the same for touching the HLG.
So far I have only measured the Forward Voltage of each strip.
19.72, 19.72, 19.72, 19.73, 19.76, 19.78, 19.91
Mean Well driver temp: 61.5° C
Seven BXEB-L0560Z-30E2000-C-B3
Powered in series by one HLG-240H-C1400B
With the HLG at max:
Wall watts: 220 watts (probably more than 1400mA)
Temperature: 59° C @ Tc2
The Mean Well driver is much hotter than the strips.
I can touch the strips for a few seconds without swearing. Cannot say the same for touching the HLG.
So far I have only measured the Forward Voltage of each strip.
19.72, 19.72, 19.72, 19.73, 19.76, 19.78, 19.91
Mean Well driver temp: 61.5° C
wietefras
Well-Known Member
Again, the irony ...
This is not about "ISL" being something that exists in general, but specifically about the distance between the fixture and plant canopy.
overdriver
Member
did anyone ever compare a COB grow vs strips grow?
Last edited:
tomate
Well-Known Member
Its COB and not CBO and take a look at "Insane In The Brain" his grow at gch.
overdriver
Member
just a typo.
I'll have a look there once I find it.
overdriver
Member
What does it need to keep a 4ft samsung f-series strip cool?