Bad News About LED vs HPS

BobCajun

BobCajun

Well-Known Member
InTheValley said:
Here are my numbers on this,

First off, my Par meter was calibrated with A-Mars factory, B- Mars with lenses, Mars300 with lenses is 1500 par at 18inches, No BS, unreal huh? Thats without messing with the spectrum. I replaced over 40 diodes to 4000k and 6 Fullspectrum 3W diodes, this rig is running at 125 watts at the wall

12inches-1999 MAXED
LUX=80,000

18in- 1300 PAR
47,000 LUX

24in 800 par
29,000 lux

33 in 450 par
16,000 LUX

My scrog is at 33 inches.

and at 33inches, its only 1500 FC and 4,500 FC at 18inches
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It's crazy how much light these things crank out, at least right in front of them. An interesting thing I found is that with a 14w LED "bulb" with diffuser cut off if you take a reading right up in front of the diodes, like just almost touching them, it's still only 9000 fc, whereas down farther under an array of said bulbs amounting to about 30-40w /sq ft it's 8000 fc. So the thing with these LEDs is that it's actually impossible to get beyond a certain brightness by getting closer after a certain point. Weird thing is that plants can still get bleached under a 14w bulb, even about 4-6" away. Maybe it's just plain heat that does that, idk.

Maybe the most amazing thing to me about the LEDs is how they maintain brightness even at considerable distances, I guess because their light is directed downward more than with an arc tube or filament so it may not drop off drastically like those point sources.
 
BobCajun

BobCajun

Well-Known Member
wietefras said:
Again, that's not how any of this works. Leds do not defy physics. Your sensor is just faulty or your interpretation is.
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The cheap meter is probably inaccurate. Oddly, photovoltaics are more sensitive to the red and IR part of the spectrum than below, so you would think LED light would read lower than the sun or HID lamps. Maybe LEDs are even brighter than I thought before I saw the graph.

But I have one LED bulb that's dimmable and I put a regular light dimmer on the power cord and at lowest power the reading is still pretty high and when turned up the needle slows down, it's not linear. It seems to read low light levels higher than they probably are. It did seem odd to me that the numbers on the meter were all equally spaced. How realistic is that likely to be? I knew that thing was a piece of crud when I paid probably $20 something for it, but had to give it a shot.

https://en.wikipedia.org/wiki/Photodiode
 
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CobKits

CobKits

Well-Known Member
id throw that meter in the trash tbh.

you can use it to balance your garden for one spectra but completely disregard any numbers it gives you
 
CobKits

CobKits

Well-Known Member
BobCajun said:
It's crazy how much light these things crank out, at least right in front of them. An interesting thing I found is that with a 14w LED "bulb" with diffuser cut off if you take a reading right up in front of the diodes, like just almost touching them, it's still only 9000 fc, whereas down farther under an array of said bulbs amounting to about 30-40w /sq ft it's 8000 fc. So the thing with these LEDs is that it's actually impossible to get beyond a certain brightness by getting closer after a certain point. Weird thing is that plants can still get bleached under a 14w bulb, even about 4-6" away. Maybe it's just plain heat that does that, idk.

Maybe the most amazing thing to me about the LEDs is how they maintain brightness even at considerable distances, I guess because their light is directed downward more than with an arc tube or filament so it may not drop off drastically like those point sources.
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this entire post defies physics and logic sorry
 
BobCajun

BobCajun

Well-Known Member
I was just testing out a 14w LED bulb in a square dollar store container lined with foil, containers like in this image. They have squares and rectangulars. The recs are good for a little larger grow chambers. The square was just a rooting chamber.


Image source

So anyway the top half of the square chamber works well just as a standalone light fixture, being kind of pyramid shaped to help make a nice square beam. I found that the 14w bulb without diffuser (cut off so about 1/2" remains for ease of screwing in the socket) appears to be able to light a 2'x2' area quite nicely, all areas getting 6-7000 fc by the cheap meter. With a 2.5' area the edges drop off too much but it works very well with just a 2'x2'. I could feel the light on my hand. That size square is about 9" from the container/reflector opening, so probably 16" from the diodes.

I'd swear you could grow stuff in that square, with about 3.5w /sq ft. It actually makes a very even looking illumination over the square. You wouldn't believe how bright a square you get when you point that thing at a white wall, even when it's 3-4' across. Who needs to buy costly grow lights when they can get the super square beam 14w grow light? I guess four of them would be required for a 4'x4' tent. With a full 56w of power in there you should be able to pull down a lb or two, get like 8 g/w.

Here's the kind of sockets I use. You just make a 2" hole in the bottom of the container with a hole saw drill bit and pull the socket into it until that lip near the opening snaps through. It'll stay right in there. The metal socket helps heat sink the LED heat away.


http://www.homedepot.com/p/1-LampHolder-with-Gasket-White-S500WHEG/204193186
 
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CobKits

CobKits

Well-Known Member
those 14W leds are great for cuttings

in your box you are measuring a significant portion of reflected light which is why its somewhat independent of distance from bulb itself

that peak response of that meter is almost entirely outside of the range of phosphor LED and is more useful for tungsten filament, halogen, sunlight and other light sources with tons of IR. most of what youre measuring with that meter is outside of par range and useless to plants
 
BobCajun

BobCajun

Well-Known Member
CobKits said:
those 14W leds are great for cuttings

in your box you are measuring a significant portion of reflected light which is why its somewhat independent of distance from bulb itself

that peak response of that meter is almost entirely outside of the range of phosphor LED and is more useful for tungsten filament, halogen, sunlight and other light sources with tons of IR. most of what youre measuring with that meter is outside of par range and useless to plants
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Well how could I be measuring IR other than the heat from the base of the bulb? The opposite of what you described is what should happen, the LED reading should be lower than with sunlight or HID. Also, I took the readings right after plugging in the lamp, so it wasn't even hot yet.

I also didn't take the reading from inside a reflectorized container. I simply pointed the reflectorized container at a flat surface and took the reading from that square of lit surface, pointing it at the bulb, from the center and the edges and corners. All were in the high light range of the meter and looked bright enough for good plant growth to me. Haven't actually tried growing anything with a 14w bulb in a 2'x2' yet though. Could be miserable yields for all I know.
 
Hybridway

Hybridway

Well-Known Member
Ill give you guys a side by side by side & if my mini-splits in, by side.
This section seriously lacks real outcomes.
Sure, theories fly around for days based on tech info.
Talk about higher efficiencies & outdated HPS. Where's the real grow documentation anymore.
 
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BobCajun

BobCajun

Well-Known Member
ganjamystic said:
wow.. just.. wow
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Impressive huh? At least my stuff isn't a carbon copy of about 1000 other people before me, like I'm guessing probably you and Johnny boy. You guys discuss me a lot more than I discuss you, that's for sure. This post is all of it. Probably because you guys never posted anything worth mentioning that I can recall. I invented the 14w Super Square Grow Light. What have you invented lately?
 
a mongo frog

a mongo frog

Well-Known Member
CobKits said:
this entire post defies physics and logic sorry
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Yea but didn't you post with your sock account earlier on leaf saturation point via ppfd on that other thread? I could be wrong and that may not be yo, but that post was completely ridiculous. Then went on trying to school us (if that was your sock) on how cannabis business should be measuring success.
 
ZeroTrousers

ZeroTrousers

Well-Known Member
BobCajun said:
Impressive huh? At least my stuff isn't a carbon copy of about 1000 other people before me, like I'm guessing probably you and Johnny boy. You guys discuss me a lot more than I discuss you, that's for sure. This post is all of it. Probably because you guys never posted anything worth mentioning that I can recall. I invented the 14w Super Square Grow Light. What have you invented lately?
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... you are aware that the greatest fraction of the flavorful terpenes will volitalize at well below the temps you claim to cure at, right?

Also, being "different" isn't the same as being "innovative". Doing things contrary to physics, chemistry and common sense makes you kinda goofy.
 
Yodaweed

Yodaweed

Well-Known Member
CobKits said:
lolwut? i dont have a "sock account". if i have something to say ill say it right to you
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The account you are posting from right now is a sock account, your original account got ridiculed so you started another one so you could act like you know something.

You probably got a dozen more so you got someone to agree with you.
 
Abiqua

Abiqua

Well-Known Member
Yodaweed said:
The account you are posting from right now is a sock account, your original account got ridiculed so you started another one so you could act like you know something.

You probably got a dozen more so you got someone to agree with you.
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lol, the TOS states to become a PAID advertiser you must only have 1 account. Genius around here, I'll tell yah......and what a pithy strawman to boot.
 
Yodaweed

Yodaweed

Well-Known Member
Abiqua said:
lol, the TOS states to become a PAID advertiser you must only have 1 account. Genius around here, I'll tell yah......
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1 account per email, any of us can start another account with a new email

Let me spell it out for you cause i know you are dumb

@CobKits is @BOBBY_G


Greengenes707 said:
Here is more from the same thread from a year ago I keep pulling things from. Not the first time, and surely not the last time we will go around this merry go round.
The main goal is always the same...

Maybe your name change from @BOBBY_G made you forget @CobKits. Give it a re-read...
https://www.rollitup.org/t/3500k-vs-4000k-vs-5000k.910643/

More to read...
https://www.rollitup.org/t/farred-photosynthesis.842295/
https://www.rollitup.org/t/summer-2014-led-growing-notes.837071/
Classic...
https://www.rollitup.org/t/cree-cxa-3000k-80cri-spectrum-analysis.832666/
Great, but new phosphors make a better case, but the principals and data is all still valid
https://www.rollitup.org/t/cxa-3000k-80-vs-93-cri-an-estimation.833171/
Click to expand...
 
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