Light Intensity; LED vs HID
- Thread starter BM9AGS
- Start date
Atulip
Well-Known Member
My man you got like 3 people trying to explain it to you. Light is light. If you want your low watt cobs to act like a HID, then cram them together in a single fixture and hang it high in the center. (Look at spectrum king for a commercial example like this)
Personally I'm gonna unsub and move on, I'm out of troll food.
Personally I'm gonna unsub and move on, I'm out of troll food.
BM9AGS
Well-Known Member
Bullheaded? Are you saying I'm bullheaded? Haha. Word up man. I'm gonna go bite my fingers and watch my solar city shares.
no your not interpreting it correctly.
-assume I have a single point light source that provides 1000 umoles.
-assume further that its set at a height to distribute its light over a 5x5 area with minimal wasted light going up or sideways, using the inverse square law to estimate height from the top of the canopy.
-assume that you haave 4 point sources of light that are 250 umoles each.
-assume that you spread out the four lights to cover the 5x5 area with minimal wasted light using the inverse square law and evenly overlap between the four different point sources.
The 4 point sources of light will penetrate deeper and provide more even coverage than a single large point source for the 5x5 area
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churchhaze
Well-Known Member
I don't use lenses or reflectors. The outsides of the wide 120 degree cone (as well as the light not within the cone) works great for low profile setups.
The outside of the cones provides a ring of lateral lighting for the plants around it rather than just overhead lighting to the plant directly underneath . When all of these overlap, the "penetration" is great. Every top receives light from directly overhead and from 60 degrees on each side.
The outside of the cones provides a ring of lateral lighting for the plants around it rather than just overhead lighting to the plant directly underneath . When all of these overlap, the "penetration" is great. Every top receives light from directly overhead and from 60 degrees on each side.
solar city just got a big bail out, they have been failing. Love the long term vision, but currently they are no more than a financing play.
kmog33
Well-Known Member
If light a puts out 2
And light b puts out 1/4
And they are dispersed at the same rate(inverse square law) when you decrease to the point where they are at half of their initial intensity.
Light a now is putting out 1
And
Light be is putting out 1/8
1/8 isn't half of 1, but both lights are dispersed an equal amount, by 1/2.
The issue is you didn't start with the same amount of light.
They were both affected by the environment the same though.
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And light b puts out 1/4
And they are dispersed at the same rate(inverse square law) when you decrease to the point where they are at half of their initial intensity.
Light a now is putting out 1
And
Light be is putting out 1/8
1/8 isn't half of 1, but both lights are dispersed an equal amount, by 1/2.
The issue is you didn't start with the same amount of light.
They were both affected by the environment the same though.
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BOBBY_G
Well-Known Member
sorry were gonna have to agree to disagree. i said put cobs at same distance to canopy as HID and add enough cob wattage to match PPFD at canopy. youre missing the point entirely. when determining "penetration" (intensity of light "b" at a certain depth under canopy, relative to the ideal intensity "a" you should have at the canopy), there is one and only one factor which determines the ratio of a:b at a given depth below canopy and thats the distance of the light source from the canopy.
i can also reach the proper intensity with a wall of t8 bulbs or a bunch of underdriven single die leds an inch from the canopy or even a bunch of 70W HID bulbs. again for a given ppfd at canopy penetration is greatly reduced with this distance.
https://www.cdiweb.com/ProductDetail/CLU5503626C1353M2G2B24-Citizen-Electronics-Co-Ltd/578624/
120 lm/W @ 538W, 35mm LES
i can also reach the proper intensity with a wall of t8 bulbs or a bunch of underdriven single die leds an inch from the canopy or even a bunch of 70W HID bulbs. again for a given ppfd at canopy penetration is greatly reduced with this distance.
sure. smaller than a filament in fact
https://www.cdiweb.com/ProductDetail/CLU5503626C1353M2G2B24-Citizen-Electronics-Co-Ltd/578624/
120 lm/W @ 538W, 35mm LES
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whats an elevator pitch ? sorry haven't had my morning wake an bake yet
puffenuff
Well-Known Member
An elevator pitch is something that can be summed up during a brief elevator ride. A sales pitch if you will. It's a term used in the business world. Something concise and to the point.
BM9AGS
Well-Known Member
Ok let me remove light types from this.
ANY LIGHT that produces 1000 PPFD AT 6 inches from source will only be producing 500 PPFD at 8.1 inches from source. So it's providing 2.1 inches of 1000-500 PPFD on and in to the canopy.
ANY LIGHT that produces 1000 PPFD AT 24 inches from source will only be producing 500 PPFD at 34 inches from source. So it's providing 10 inches of 1000-500 PPFD on and in to the canopy.
Are there any objections? I'm talking here about single light source no side lighting no wazoo tricks.
If there's objections then I'm sorry but contact the invers square law calculations invented by a dead scientist. These are facts!
ANY LIGHT that produces 1000 PPFD AT 6 inches from source will only be producing 500 PPFD at 8.1 inches from source. So it's providing 2.1 inches of 1000-500 PPFD on and in to the canopy.
ANY LIGHT that produces 1000 PPFD AT 24 inches from source will only be producing 500 PPFD at 34 inches from source. So it's providing 10 inches of 1000-500 PPFD on and in to the canopy.
Are there any objections? I'm talking here about single light source no side lighting no wazoo tricks.
If there's objections then I'm sorry but contact the invers square law calculations invented by a dead scientist. These are facts!
dude THINK where did the other 500 ppf go ? and please stop confusing PPFD with PPF.
OneHitDone
Well-Known Member
So what you are saying HID is still going to outperform cobs even boxed around trees? Under-driven cob diminishes so quickly it won't penetrate the length of the branches by what is being stated here.
What do you guys think is going on in this setup as far as par #'s at the plant canopy in different locations?
JorgeGonzales
Well-Known Member
Light isn't lost. This is all you are missing.
kmog33
Well-Known Member
Sure, as I explained...
Start with a bigger number, see a perceptively smaller decrease in a logarithm.
That's math. And you're really just not comparing anything that makes sense in a practical situation.
What is the point of your argument?
That a point source light with 50x as much light as another also takes longer for the photon density to disperse?
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BM9AGS
Well-Known Member
Fig 1
Actual meter readings at 12 and 18"
Fig 2 calculations for reduction of light from 12 to 18 inches.
It doesn't calculate reflection that's likely happening. But they're close enough.
So the calculator is wrong and so are the actual PPFD meter readings according to you?
oh goodness I fucking give up try to help somebody and all I see are rocks in the head.
GET OFF OF THE CALCULATOR AND STEP BACK AND LOOK AT WHAT YOU ARE SAYING
Look up the difference between PPF and PPFD and account for the overlap in multiple smaller sources AT THE SAME AMOUNT OF TOTAL LIGHT and OVERLAP between multiple point sources.
GET OFF OF THE CALCULATOR AND STEP BACK AND LOOK AT WHAT YOU ARE SAYING
Look up the difference between PPF and PPFD and account for the overlap in multiple smaller sources AT THE SAME AMOUNT OF TOTAL LIGHT and OVERLAP between multiple point sources.
JorgeGonzales
Well-Known Member
I lied, the other thing you are missing is that PPFD is a spot reading.
It's like a garden hose man. You can make a narrow stream and blast it in the middle of your lawn, and all you will do is kill the grass there. We want a wide, EVEN stream. That's what HID reflectors do, or multiple light sources, or lenses.
The inverse square law means less light for a given area, because light spreads, it doesn't disappear.
And has anybody bothered pointing out that the second you add a lens or reflector the inverse square law doesn't even fucking apply?
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weed-whacker
Well-Known Member
oh i get it
this
penetrates better than this
even though the same amount of photons are being released?
cool thread dude, can you start one about how magnets can be used to increase yield?
this
penetrates better than this
even though the same amount of photons are being released?
cool thread dude, can you start one about how magnets can be used to increase yield?