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Gimme5minutes

Can anyone explain some LED science?

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My old LED UFO died recently, it had been opened up and serviced a few times over the years but it finally overheated and conked out. It had some of the first 3W LEDs (15 of them) and lit up a room like the bat signal. The person I lent it to kindly replaced it with one he picked up. This light is 450W (45 x 10W) but only runs an actual 65 Watts. Its not very bright unless its 8 to 10 inches from the surface and even the it covers an area of almost 1 by 2 feet. I asked the guy about it and he assured me this was normal, he claims its not about how bright the LED is but about how much usable photosynthetic light the LEDs give off. I don't really have a head for science so all this sounds fishy to me, can I get a second opinion?

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It seems strange for an LED with 450 watts max capacity to only consume 65 watts. That's not going to be bright enough to illuminate more than a square foot. Something doesn't add up.

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Would be hard to give you an accurate answer without knowing what brand the light is, but yeah, that sounds fishy. My Platinum LED is a “450” but draws about 180-260 Watts, and I’ve yet to see a decent LED that wont blind you. I’d suggest googling whatever it is he gave you.

 

But I would also say if he’s replacing an older model with something similar, they are nowhere near as good as the LEDs of just the past couple of years. All the decent lights today have very broad spectrums,including uva/uvb coverage.

 

Does the sun blind you when it’s on?

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Something definitely doesn't add up. My 90 Watt LED still used like 45 Watts. The brand is Wattshine (its in big letters), they have LED lights for growing and for aquariums. You can pick one up for less than $100. Their websites features some contradicting information. One point it claims to be used to cover an area of 8 by 5 feet and another an area of only 18 by 20 inches...some crap about high PAR values. It's easier for them to blind me with their science than their shitty LEDs. But still, 65 Watts?

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Ok, "watts" in LED's have NOTHING to do with the actual power consumed by the light. They may have to do with the number of diodes in the light, i.e., 150 3 watt diodes equals a "450 watt" LED. But most often, they have to do with the replacement value vs HPS lighting, such as a "600" watt LED will equal the results of a 600 watt HPS, etc.

 

The whole idea of LED lighting is to provide a more efficient usable spectrum at a reduced cost compared to the HPS or Halides, and if I do say so myself, today's lights are accomplishing that quite nicely. BUT, if you come across a light that uses a suspiciously low true wattage, compared to the advertised watt replacement value, it's more than likely a sub par unit, or, an "el cheapo", and there are tons of them out there. Yet even some of those give reasonable results, Mars, and Viaspectra, are a few Amazon top sellers that I would suggest fall into this category.

 

Like all of life, you get what you pay for. if you want to know about power consumption, READ. Go to Kind, Black Dog, California Light Works, Advanced Platinum, Illumitex, all of which are top shelf lights, with tons of grow blogs proving it. Lot's of folks also swear by Mars, too, so not to dis anyone. But a 450 "watt" light that costs 150 bucks on eBay, is not going to compete with a Black Dog 400 that costs 800. Period. You'll also find the better lights, while not using the advertised power, will come closer to it than the cheapos, but even the best will be a few hundred watts under their replacement values, that's the whole point of LED's.

 

I love LED's!!! Having grown with HPS for years, I made the switch, and will never go back, no reason too, a great LED grows better bud, and they do it faster and more efficiently, IMO. But you've got to do your homework if you want to know what's true and what's not.

 

BTW, I'm running one 600 Platinum in my main grow space, and I will NOT enter the space without my 10 dollar pair of grow room sun glasses, 100% UV protection, seriously! Most of these things will blind you.

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It's about heat, The "D" in led stands for diode, a diode needs a certain amount of voltage to "Turn On" as it gets hotter it gets more efficient producing more light and heat per unit of electricity consumed, which meant it gets hotter and more efficient, which causes it to become even hotter and more efficient, the cycle continues until there's a pop and a wisp of what's known as "Magic Smoke" in the led industry :)

 

So manufacturers limit how much juice each diode can get so they don't overheat, the higher quality the led unit is the better the cooling and the more juice each emitter can take before overheating.

 

I don't know if it's still the case but when I looked into it a few years back lower wattage emitters could handle more juice than higher wattage emitters with the sweet spot being at around 3 watts, my 50w UFO with 2w emitters draws 43w, while my 600w panel with 10w emitters draws 124w.

 

about brightness, brightness is a word to describe how the human eye rates light levels, since plants don't have eyes brightness is irrelevant to discussions on grow lights because most of the light that we see is useless to the plant.

 

the proper term is Photosynthesis Active Radiation which is the part of the light spectrum that plants can use which tends to be at the edges of the spectrum, I've read that this is because plants evolved deeper in the water where the bands of light in the middle of the spectrum couldn't penetrate or were used up by mycopid species but I've never looked into it.

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I've never seen a high PAR luminaire that wasn't visibly bright to the eyes.

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Yeah basically LED watts don't mean anything.

You have to look at wattage from the wall.

 

Also, the efficiency of the old LED like what you find on amazon is about 1.3 umol/J which is almost less than HPS so you are really wasting your money with those lights, plus they leave out important colors for your plants and look a strange purple color, peace.

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One fun thing, all PAR light is also visible to the human eye so the statement "its not bright because its good par light" only shows how your buddy has no idea what he's talking about.

I blame bad sellers for sharing bad info on leds so a lot of people get very confused on led topic.

Best efficency leds are cob leds and quantum boards, so find a light which can provide infos on chips used(also pics!) and states the total draw watts, any other mumbo-jumbo sellers should be forgotten and left to rust.

 

Cheers

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After about a month with this light I can honestly say its not too shabby. I have it in a tent with CFL and HPS light and I can't see anything negative, plants near the edges of the light seem to bend inward towards it. The fan is too loud and it puts out very little heat, much less than the CFLs. The leaves can be a quarter inch away and they'll be fine. It would be really ideal for someone growing short plants in a tight area, like a microcab, it covers about one and a half square feet comfortably.

The science behind it seems like bullshit and probably is. Still it does its job.

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When looking into LED especially the ones like what I am using...  Research PPFD (Photosynthetic Photon Flux Density)

My LED unit for vegetative growth 

My LED unit for flowering growth
If I ever get to rebuilding the flowering light, I would use similar heat sinks to the ones used in the vegetative light.

At full power and within the small grow space, my vegetative light pushes around 750 ppfd and the flowering light pushes around 1500ppfd.

6500k is about the same as "High noon" and 3500k is about the same as "Golden hour." Our solar system's sun emits about 5% UV.

Here is a video for more information...

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