The end of LED is nigh. Incandescent will rise again.

Sativied

Well-Known Member
Very funny. It's not like that at all though, just because I disagree with some skewed claims about led and hps doesn't mean I'm anti-led. I'm all for LED technology and lower energy use, globally. I'm just interested in more than just par watt efficiency. Not my problem if that puts a few cracks in the picture led fans have painted on those efficiency numbers alone.

COBs are just an example of LED technology, unlike professional horticulture hid lighting not designed for growing plants. White cobs only make sense when you want to throw money up fron to reduce the electricity bill in an attempt to beat hps. Not if you want to utilize all the potential of LED technology for growing plants. Surely I appreciate LED technology a lot more than you hps-warming deniers.
 

OneHitDone

Well-Known Member
I just don't see why everyone get's all butthurt and offended when someone brings up other discussions besides the new CXB...yada..yada....yada
Dude has not said all led blows and has no place.
I for one find all the tech interesting to follow along and just think about
One could take all this in a realize that you really need two lighting systems - HID for winter growing, and switch over to led when the summer heat rolls in.
It really is looking like not one tech is "best" - gotta pick what fits best with the current conditions at hand
 

Sativied

Well-Known Member
"IR up-conversion phosphors are particles that convert infrared light into visible light.

Up-conversion materials are a very rare class of inorganic crystals that can absorb multiple photons at a lower energy level and emit one photon at a higher energy level. The up-conversion process is also called an Anti-Stokes shift
."

Surely the commercial led builders here are aware of stokes shift and phosphor trickery making leds less efficient for photosynthesis and more suitable for streetlights and store displays.

Anyway, 40 bucks for 5 grams of a very rare class of impossible crystal technology from the future: http://www.maxmax.com/shopper/product/15399-irspg-5g-ir-up-conversion-storage-phosphor-green-emitting-5-grams

Dissolve 1 tsp in 1liter RO water and spray on the plants weekly and the bulb and reflector once per cycle. ;)











 

Corso312

Well-Known Member
You come off as a crazy man @Sativied ... I've only gotten one harvest from a led light (DIY Vero) that a friend built..it was impressive until it stopped working.. I run HPS and heat is always a pain in the dick, even in winter I have to cool the Air cooled hoods and I'm in the North.. I can't wait to Replace every 1k light I have with passive Cobs.
 

Sativied

Well-Known Member
Really... well I find it "crazy" to consider only par watt efficiency when comparing or replacing hps with led.

"Every 1k light" suggest you run more than a couple of bulbs in which case an exhaust alone often won't do. When heat from hps is a pain in your dick in a moderate climate you're doing something wrong. Not exhausting outside for example. It's roughly 61-78 in the room my grow closet is in. I have a 59 watt exhaust that usually runs much softer than max for one 600w. Plenty of people growing with 1k gavitas in tents (5x5x7 for example), all it takes is a good exhaust.

Not sure what you read when reading this thread but I'm not suggesting you don't switch to led do I. If however you managed to reach optimal temperatures under hps it would be wise to realize the ambient temp needs to be a little higher under led to reach the same plant and leaf temp. In general led has shown to be a good alternative for those having a hard time growing indoor with high-end professional horticulture lighting.
 

a senile fungus

Well-Known Member
Are there any real #s on comparisons of photosynthetic rates of cannabis grown under LED and HID at a specific ppfd and canopy temp?
 

Stephenj37826

Well-Known Member
I just don't see why everyone get's all butthurt and offended when someone brings up other discussions besides the new CXB...yada..yada....yada
Dude has not said all led blows and has no place.
I for one find all the tech interesting to follow along and just think about
One could take all this in a realize that you really need two lighting systems - HID for winter growing, and switch over to led when the summer heat rolls in.
It really is looking like not one tech is "best" - gotta pick what fits best with the current conditions at hand

Did you read the title to the thread???????
 

GrowUrOwnDank

Well-Known Member
I just don't see why everyone get's all butthurt and offended when someone brings up other discussions besides the new CXB...yada..yada....yada
Dude has not said all led blows and has no place.
I for one find all the tech interesting to follow along and just think about
One could take all this in a realize that you really need two lighting systems - HID for winter growing, and switch over to led when the summer heat rolls in.
It really is looking like not one tech is "best" - gotta pick what fits best with the current conditions at hand
Perhaps I am different and I have ZERO scientific evidence to validate my methods. But, I use HPS and the old Blurple style LED sold by the same people who are Mars. I don't even remember when I bought it it's so old maybe 5 years and I have a generic Chinese that is even older. And I've been known to use all of them and also CFLs. The little household ones when they are small then a giant 65 watter as they get larger and even in flower. I would like to try a cob but, everything works well already so... I feel good about having all those different spectrums from the dirterent sources. Why choose? Run them all.
 

frica

Well-Known Member
Here's one for you. If we are going to talk about tech that may or may not ever actually materialize......

http://www.zmescience.com/research/led-over-100-percent-efficiency-mit-94323/

In the meantime do some research...... There is a 2.7 umol/j monochrome greenhouse fixture available right now.......
Interesting but that LED uses surrounding heat as an additional energy source so it's almost certainly not going to work at scales large enough for plants.
 

a senile fungus

Well-Known Member
Not that I know of, but cobs are blue/red heavy and do a good job of emulating the Mcree curve. He's not suggesting equal canopy temps though.

He's not? I've seen him mention multiple times that HPS will warm the surface of the leaf above ambient room temps, resulting in higher leaf temp, and photosynthetic rate. And that he suggests that LED users, because of lack of IR radiation, would need to increase the ambient temp to subsequently increase leaf temp, to reach similar photosynthetic rates, at the same ppfd.

In my words, the efficiency numbers you guys make the end all, end all, are really just moving the goal posts to make the tech more attractive. Ppfd doesn't directly translate into grams. Pure plant metabolism translates into grams. So why not use a metric that measures electrical efficiency of light vs photosynthetic rate or metabolism?

If however you managed to reach optimal temperatures under hps it would be wise to realize the ambient temp needs to be a little higher under led to reach the same plant and leaf temp.

Everything else being equal, same ppfd, led needs higher ambient temp to result in the same leaf temp and thus same photosynthesis and metabolism rate.

If one replaces a 900ppfd hps setup with 900ppfd led, everything else being equal, amd no extreme temps, the hps would result in more photosynthesis. Leaf temp matters... Obviously the spectrum of the led can be more efficient for photosynthesis, more blue and especially red, which makes the white cobs so ironic. The worse the spectrum for photosynthesis, the better for warming plants.
See my recent 10 or so posts in this forum, in the de bulb thread. It's an issue in multiple ways. High ppf requires a high leaf temp for optimal photosynthesis. Cannabis requires similar temps for optimal metabolism. The ambient temp needs to be higher with led to achieve the same leaf temps. Blasphemy according to the Bibled thumpers here but a well recognized issue in tons of research and side by side performed by universities and experts.

Quite a few more honest led light designers agree, some even add IR.

"When growing under optimized-spectrum LED plant lights, the lack of excess infrared and other unusable light causing the leaves to heat up means that ambient air temperature needs to be warmer than for the same plant grown under any light (natural or artificial) which is not optimized for plant growth."

"When growing with plant-optimized LED lights, it is important to realize that ambient air temperatures need to be kept higher compared to other lighting to achieve the same metabolic rate. "

Using white leds only partly makes up for this issue. Especially those low in red, the most efficient for photosynthesis lol... and high in non-blue/red. The crappier the spectrum of the white cob, thus the less usable light in the optimal wavelengths for photosynthesis, the better they will be for warming up your plants... Ironically, led fans have taken the heat thing to a simplistic black and white level. They are essentially willing to sacrifice a major advantage of led (light quality control) by spending par watts on warming up the plants. And missing out on the full potential of led, blinded by par watt efficiency numbers and hps-envy.

The claim led runs cooler and is therefor better is typical led marketing from led companies (and thus led shills and fans). Horticulturists and unbiased pros often have a different view... The IR increases the leaf temp more than the ambient temp. Ambient temp needs to be higher under led than under hps in reasonable circumstances to be able to match hps. This negative is turned around into a positive, which led fans take a step further by pretending hps creates too much heat.

"LIGHT & INFRA-RED

Both sunlight and HID light sources produce copious amounts of Infra-Red (IR) radiation. IR is effectively heat, but it only exhibits that heat when absorbed by something. This means that IR can pass innocuously through the air having little effect on its temperature because air is transparent and absorbs little IR. But when it strikes the leaf of a plant, it is absorbed and it heats the leaf. There is some evidence to suggest that IR closest to the visible range can enhance the red band absorption of chlorophyll, but IR’s effect on the plants leaf temperature and metabolism are more pronounced. As an example, if your room temperature is 78f using HIDs, the IR striking the leaves will increase the effective leaf temperature by 5-7f. This means that while you THINK your room is operating at 78f degrees, the plant is actually seeing 83-85f.
[...]
It’s a common misconception that LED grow lights cannot compete with HID purely in terms of yield. Actually LEDs simply require an increase in ambient temperature for comparable results with lower energy consumption and heat generation. LED-based light sources differ from sunlight and HID not only in their duo-chromatic, photo-synthetically tailored spectral output, but also in the fact that they produce virtually NO IR. So a plant growing in a room with HIDs at 78f will actually exhibit the metabolism of a plant at 83-85f, while the same plant in a room with LEDs at 78f will only have a 78f metabolism rate.

Tip #1 -So when you flower with LEDs, you must raise the room temperature 5-7 degrees f higher than you would run with HID, with all other conditions equal.
"

"Disadvantage of LED.
LEDs do not emit that much radiant heat. Conventional lighting systems, especially HPS, can produce heat to warm up and dry leaf surfaces faster. Radiant heat from the lighting can be an advantage in certain circumstances, such as in keeping leaf surfaces dry in order to reduce the occurrence of powdery mildew. This is one of the reasons that some greenhouses are using mixed LEDs and HPS in their production environments".
-Dr. Youbin Zheng, University of Guelph

University of Wageningen tested it too, on a huge scale, and it's a simple fact that LED requires higher ambient temps than hps.

https://www.blackdogled.com/bloglst/ This led company presents a fairly honest view on the matter.

What it comes down to is that the lack of radiation heat from led can be both an advantage and a disadvantage. Just heating to the point where ambient temp is equal is not enough.
 

Stephenj37826

Well-Known Member
Interesting but that LED uses surrounding heat as an additional energy source so it's almost certainly not going to work at scales large enough for plants.
This is true in some cases. There are areas that generally need AC no lights at all even in 70% of the year. Actually if it steals the heat from the air to make light . 98%+ of that light will turn back into heat......
 

GroErr

Well-Known Member
Good discussion, minus the dick slinging contest between hps and LED, it's sounding like a Mac vs. PC conversation. Heat/RH management and extremes one way or another are relevant and should be considered when choosing your lighting tech. These modified incandescents are interesting tech but still a few years away from being on the shelf, if it ever makes it. The more options the better if they can eventually put a bulb out with the right growing spectrum and more balanced heat output.

That said, I agree with the principle point of providing not just par watts but some heat. I just had a similar conversation stating I wouldn't go all LED COBs for my main flower room because it would create more problems than it solves, including insufficient heat and higher RH to deal with. Too little heat (e.g. actively cooled LED) is as bad as too much or difficult to manage heat (hps). Less heat = higher humidity and imo RH is more difficult to control as well as having the potential for mould/PM issues. That would require then running a dehumidifier which is as expensive as running air conditioning, and negate the benefits (supposed savings) of the cooler LED's. Although passively cooled LED's with the right wattage for the space could help manage that somewhat.

Setting aside any potential new tech which may or may not get to market we have choices to make using existing tech. Those choices to me depend more on your room/environment than whether it's hps, LED, or any other tech. Setting aside personal preferences, a logical choice should be based on your space to be managed more than whether it's one tech or another. I chose to use COBs in a small (2x2x4') tent because it fits in there nicely and gives me the temps/RH I like in that space using passive intake and a small 4" booster fan for exhaust, it doesn't get any easier/simpler than that. In my veg cabinet and veg tent I use blurple LED's for the same reason, smaller enclosed spaces which would require more elaborate and costly ventilation/exhaust systems and associated costs/hassles. In my main flower room I use multiple smaller CMH lights since I run perpetual in there and CMH fits in that room nicely, giving me the temps I want without a lot of elaborate cooling/heating systems, taking advantage of the heat they output to manage the environment (heat for CMH is somewhere between hps and LED). If I went 100% LED in there I couldn't run enough wattage to maintain the temps/RH I want with the square footage available (without compensating for it like running a dehumidifier constantly). If I were running hps in there, the environment controls would need modifications and/or I'd have to run lower wattage lamps. It's a balancing act and utilizing the advantages of available tech available to fit the space vs. the tech itself imo.
 

Stephenj37826

Well-Known Member
Good discussion, minus the dick slinging contest between hps and LED, it's sounding like a Mac vs. PC conversation. Heat/RH management and extremes one way or another are relevant and should be considered when choosing your lighting tech. These modified incandescents are interesting tech but still a few years away from being on the shelf, if it ever makes it. The more options the better if they can eventually put a bulb out with the right growing spectrum and more balanced heat output.

That said, I agree with the principle point of providing not just par watts but some heat. I just had a similar conversation stating I wouldn't go all LED COBs for my main flower room because it would create more problems than it solves, including insufficient heat and higher RH to deal with. Too little heat (e.g. actively cooled LED) is as bad as too much or difficult to manage heat (hps). Less heat = higher humidity and imo RH is more difficult to control as well as having the potential for mould/PM issues. That would require then running a dehumidifier which is as expensive as running air conditioning, and negate the benefits (supposed savings) of the cooler LED's. Although passively cooled LED's with the right wattage for the space could help manage that somewhat.

Setting aside any potential new tech which may or may not get to market we have choices to make using existing tech. Those choices to me depend more on your room/environment than whether it's hps, LED, or any other tech. Setting aside personal preferences, a logical choice should be based on your space to be managed more than whether it's one tech or another. I chose to use COBs in a small (2x2x4') tent because it fits in there nicely and gives me the temps/RH I like in that space using passive intake and a small 4" booster fan for exhaust, it doesn't get any easier/simpler than that. In my veg cabinet and veg tent I use blurple LED's for the same reason, smaller enclosed spaces which would require more elaborate and costly ventilation/exhaust systems and associated costs/hassles. In my main flower room I use multiple smaller CMH lights since I run perpetual in there and CMH fits in that room nicely, giving me the temps I want without a lot of elaborate cooling/heating systems, taking advantage of the heat they output to manage the environment (heat for CMH is somewhere between hps and LED). If I went 100% LED in there I couldn't run enough wattage to maintain the temps/RH I want with the square footage available (without compensating for it like running a dehumidifier constantly). If I were running hps in there, the environment controls would need modifications and/or I'd have to run lower wattage lamps. It's a balancing act and utilizing the advantages of available tech available to fit the space vs. the tech itself imo.
This may at surface but if you really look into a totally sealed environment (AC) you'll still be running a dehumidifier partially anyways. On the other hand if your exchanging air the humidity case is gone..... Point being if you are one who exchanges air at night during summer but battle heat cobs are the go to solution. Also as stated if you contain the heat from the led Fixtures true it's a different form of heat but the btus aren't disappearing. So the only equal ground hid has is in colder areas who are exchanging air.
 

Stephenj37826

Well-Known Member
4 1000watt de & 2 315 lec in my flower room (12x12) no AC at all..just venting the hood

I do not read to much into the PAR thing,it means shit.
What part of the country you in ? You won't get away with that in the summer in the southern states..... Unless you're exchanging a huge amount of air....
 
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