Bad News About LED vs HPS

CobKits

CobKits

Well-Known Member
i realize youre in a closet but LED and HID (including HPS and CMH) all produce considerably less heat per unit of light produced relative to fluorescent.

as a persoanl med grower the 20-50% efficiency difference is likely irrelevant, few bucks a month
 
BobCajun

BobCajun

Well-Known Member
I have the 5w LED inside a container which is lined with mylar, so it's all contained inside that 10"W x 13L x 18" H box, a little less than 1 sq ft. I don't mean severe bleaching, I mean light areas on the leaves, like near the margins. The leaves are not normal all one color type. And this is with the diffuser still on the bulb. Maybe it's not actually harmful, I don't know.

And in reply to the above post, close enough. I doubt if HPS produces more watt for watt, but it's interesting that at similar intensities the HPS won out. Maybe just due to more far red, stretchier plants more light gets through.
 
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BobCajun

BobCajun

Well-Known Member
biostudent said:
Fresh weight is the same as dry weight? lel
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Does look a little weird. They didn't think that chart out too well when they faked it I guess. Maybe it really is a cooked up sales gimmick, who knows. They'll try anything to sell an LED grow light these days.
 
ZeroTrousers

ZeroTrousers

Well-Known Member
Budies 101 said:
To me the debate on if LED or HPS is better has been over a long time. People are growing with near half the wattage of a HPS and getting near or the same yeilds they did with HPS. The cost is the issue for most when it comes to buying or even building LED lights. If in a 4x8 you had 2k watts of HPS but grew with 1k watts of LED and HPS only slightly beat LED, that does not mean HPS is better, it means that LED is almost twice as good as HPS.
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I'm firmly in the LED camp too, otherwise I wouldn't have dropped ~$650 on my Veros.

I'm just pointing out that every passing year and every product revision is pushing the technology towards a point where no one can reasonable deny that it's superior.
 
Rahz

Rahz

Well-Known Member
The 100% wet and dry weight figures are relative to 1 being the best, so max wet and dry weight should both be 1... not that I put any faith in this study. If you start taking various grows and tabulate the par wattage and yield you can determine how many grams per par watt people are getting and leave out the efficiency of the light source. I've done it here and there over several years and par watt yield is slightly higher for LED, primarily IMO because there's less reflection going on. But that aside, a par watt is a par watt. Spectrum plays a part, but a small part. Certainly not as much as this "scientific" study suggests.
 
BobCajun

BobCajun

Well-Known Member
What most people don't know is that the LEDs may last 10 years but the drivers may last about 2 before the capacitor burns out. Might be a wise investment to get fans for the drivers if they're not in a fixture with fans already. I don't know how much the cooling would extend the life though.
 
Rahz

Rahz

Well-Known Member
The first lamp I built was a 23 cob array, each with it's own driver. They were Meanwell PLM-40s which have a 2 year warranty. I ran that lamp for over 3 years. Not a single driver went bad. The second lamp I built was a 14 cob array, each with a PLM-40. I ran that lamp for over 2 years. None of them went bad. None of them were fan cooled.

Meanwell HLG drivers are rated for 7 years. They may last about 2 years but it's much more likely they may last 7 years or more.
 
BobCajun

BobCajun

Well-Known Member
Rahz said:
The 100% wet and dry weight figures are relative to 1 being the best, so max wet and dry weight should both be 1... not that I put any faith in this study. If you start taking various grows and tabulate the par wattage and yield you can determine how many grams per par watt people are getting and leave out the efficiency of the light source. I've done it here and there over several years and par watt yield is slightly higher for LED, primarily IMO because there's less reflection going on. But that aside, a par watt is a par watt. Spectrum plays a part, but a small part. Certainly not as much as this "scientific" study suggests.
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Maybe there's a better comparison somewhere. I did read another article where HPS outperformed red or blue LEDs but the extra heat from the hps may have been responsible.
 
Rocket Soul

Rocket Soul

Well-Known Member
Congrats to Bobcajun, you seem to have found some 600% efficient leds. You should hook us all up:roll:

I guess youre talking about seedlings right? I had no bleaching on my seedlings at half inch from an 8w ikea warm white led, only some marginal bleaching when the leaf was in direct contact over night. Not sure what your doing but it doesnt seem right.

Also "Bad news for led vrs HPS"? Only if you live for arguing this shit old argument on forums, data is never bad news and most people grow with what works for them. Sadly the web page provided is more than skimpy on details and when they give details it kinda shows they dont know the first thing about how to run an experiment: "exactly them same conditions"? The hps side would have higher leaf temp due to IR affecting plant metabolism

On the other side your approach is new so please go on there is nothing wrong with trying to do things differently.

Happy growing :)
 
BobCajun

BobCajun

Well-Known Member
Rahz said:
The first lamp I built was a 23 cob array, each with it's own driver. They were Meanwell PLM-40s which have a 2 year warranty. I ran that lamp for over 3 years. Not a single driver went bad. The second lamp I built was a 14 cob array, each with a PLM-40. I ran that lamp for over 2 years. None of them went bad. None of them were fan cooled.

Meanwell HLG drivers are rated for 7 years. They may last about 2 years but it's much more likely they may last 7 years or more.
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Okay, maybe the good ones last 7 years then, I had just read that electrolytic capacitors had a lifespan of only a few years because the electrolyte evaporates or whatever.
 
BobCajun

BobCajun

Well-Known Member
Rocket Soul said:
Congrats to Bobcajun, you seem to have found some 600% efficient leds. You should hook us all up:roll:

I guess youre talking about seedlings right? I had no bleaching on my seedlings at half inch from an 8w ikea warm white led, only some marginal bleaching when the leaf was in direct contact over night. Not sure what your doing but it doesnt seem right.

Also "Bad news for led vrs HPS"? Only if you live for arguing this shit old argument on forums, data is never bad news and most people grow with what works for them. Sadly the web page provided is more than skimpy on details and when they give details it kinda shows they dont know the first thing about how to run an experiment: "exactly them same conditions"? The hps side would have higher leaf temp due to IR affecting plant metabolism

On the other side your approach is new so please go on there is nothing wrong with trying to do things differently.

Happy growing :)
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I suppose you're right, it wasn't really that bad of news.
 
InTheValley

InTheValley

Well-Known Member
HPS also has over 100,000 lumens, from one fixed source, It Punks the plant into making Buds, LOL.

It be Like,
" Fruit, You Bitch ass tree",

then, Bam, Buds...

Its a lumen bully is all.
 
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BobCajun

BobCajun

Well-Known Member
Remember i said something about green light being bad over a certain amount, like 25% of the spectrum? Well I found the article, here's a quote. Not the article that says 25% but another one.
Growth of Intact Higher Plants. Removal of all of the near-UV or half of the green radiation from white light increased the fresh and dry weight, height of the plants, and the lengths of the peduncle of marigold plants (fig 2a, table I). Peduncle weight and length were reduced when either nearUV or green wavelengths were filtered but were increased above control levels when both wavelengths were filtered. Tomato plants showed a similar response (fig 2b) as did corn and bean plants. Since marigold, tomato, and corn are semi-tropical. highlight requiring species, identical experiments were performed with Impatiens, a temperate zone, semishade plant. Selective removal of near-UV and/or green wavelengths from white light caused growth responses similar to those observed in marigold (fig 2c). Thus, monocot and dicot species from widely separated families are responsive to selective removal of these wavelengths.

Effects of Near Ultraviolet and Green Radiations on Plant Growth 12
Richard M. Klein, Pamela C. Edsall, and Arthur C. Gentile
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Fortunately the green light filter gels also filter out most UVA.
 
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