# 600W Bridgelux/Cree 2 Watt plant growth light?



## zanza (Aug 7, 2010)

wanted to get anyones opinion on this, if it was a quality product worthy of interest or not.


http://cgi.ebay.com/NEW-600-W-LED-G...-Spectrum-/140437002359?pt=LH_DefaultDomain_0


its a 600W light claiming to use the latest LED lights, 2 and 3 watt strength with 5 band spectrum. Anyone knowledgeable about LED can offer an opinion on anything ?


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## Oznog (Aug 8, 2010)

You can check out the long discussions on LED plant growth here.

My technical note is that 600W requires a LOT of cooling. Hard to say whether they have enough here.


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## IMSabbel (Aug 8, 2010)

Would guess so. Looking at the pictures, they seem to have forced air cooling with 92 or 120mm fans. If the body of the light contains a resonable aluminium heatsink profile this should be enough


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## aurum (Aug 8, 2010)

It's not worth it ... There was a test (german) anywhere out there some time ago and they said it's junk and not worth to spend the money :green:


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## Ken_McE (Aug 8, 2010)

zanza said:


> wanted to get anyones opinion on this, if it was a quality product worthy of interest or not.



I don't trust it. If you read through the text it contradicts itself and has odd claims. :shakehead Approach with caution.


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## blasterman (Aug 8, 2010)

> _Your buying 600 W *FIVE*-band grow light with 2 Watts Led chips.(Blue & Violet Bridgelux.Red & Red Cree,The IR Military Grade Semileds) Bridgelux only making White and Blue Chip!_


 
Everytime I read that sentence I feel an urge to order an egg-roll and mongolian beef (with broccoli).

I wonder if Bridgelux corp knows their emitters are made in U.S.A. I'll have to send them this link and see what the response is. 

On a serious side, if the product in indeed a total of 600 watts and using 2watt emitters, then the LEDs and drivers alone are worth the money as spare parts. However, it's obvious by the text you really don't know what you are getting.

Red and blue LEDs make killer growths lights, once you get the ratios right for the specific plants. It's just that this stuff is so absurdly easy to DIY I don't know why people by these panels.


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## Oznog (Aug 9, 2010)

Well, it's NOT simple. Because even the ones sold commercially don't seem to work.

I took an interest in this after seeing the indoor "Aerogrow" garden thing (which actually does work, using fluorescent grow lights) and researched LEDs because, well, technical fetish for LEDs. It's best I just admit that upfront.

I've talked to the "hydroponics" shops in town. Well, what most customers want to grow isn't lettuce. But, probably not a big, relevant difference. The thing is, they're very critical of hardware, and the LED products have made bold claims and never lived up to them. 

Whether they don't have the radiant power right, don't have the right wavelengths, don't have the right "throw" to hit the leaves, or don't "mix" or sequence them properly, well, nobody's clear on that. But the bottom line is those particular products put on the market are neither cost-competitive nor energy-competitive with HID or even CFL for growing results (plant type not withstanding). 400W of HID can already grow a LOT of plants! CFL is less efficient, and less effective overall, but the initial investment is lower esp for a small-scale "toy" like the Aerogarden.

I'm not saying LEDs _can't_ grow plants. But, the ones made commercially up to this date cannot do so effectively. The folks I spoke to seemed knowledgeable and results-oriented rather than repeating some sort of dogma to sell their own product. They were clear they'd sell LEDs if they _did_ work- but they do not work, not in a way that was competitive with existing grow lights.

First, be aware that WHITE LEDs do not produce light more effectively. CFL grow light can do ~75-90 lumens/W. Some high-end white LEDs can exceed 100 lumens/W if well cooled and used at low power. The LED grow lights won't be. Even still, it'd only be a SMALL gain. And metal-halide HID- the standard for grow light- is like 125 lumens/W. LED won't beat it. Now it's debatable whether the single-color LED can cause photosynthesis more efficiently by hitting specific wavelengths the chlorophyll uses, and it's "interesting"- but again, field reports seem to be mixed. 

The "UFO" LED device is the most popular and heavily marketed indoor horticulture lamp. The consensus among professionals seems to be that it just doesn't work. Growth is weak and abnormal, and it was fairly expensive. Can't rule out better results if they used several times more LED lamps than recommended, but the cost was already exceeding that of a known-effective HID system.

And I, too, am skeptical that they packed "600W" of LEDs into this. Because, as noted, it seems difficult to budget the cost of 600W emitters- regardless of type- construct a housing and cooling, and still make a profit even at a $659 price tag. 

Well, I can imagine it if they took 200W nominal of emitters and ran them at triple the nominal power. There's no law that says you can't! But the lumen/W goes down a lot, so it's not really producing like a "600W" system, and the emitters won't last long.


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## blasterman (Aug 9, 2010)

Oznog said:


> Well, it's NOT simple. Because even the ones sold commercially don't seem to work.


 
Yeah, it is that simple, because I've done it along with a lot of other people :huh: Once it again it seems we're basing technology on the basis of what's available shipped from China in container ships.



> I've talked to the "hydroponics" shops in town.


 
I'll give you the skinny on these guys because I did the same thing and was also greeted with the same attitude. However, some dude making $8.50 an hour at the local hydro store doesn't qualify as a pinnacle of science in my book.

Hydroponics stores are *retailers* and in the business of selling products, and make nice mark-ups on old tech growth engines. These guys still think full spectrum fluorescent bulbs are the highest tech growth technology, etc. One actually still preferred Vita-lights. Mine actually do sell UFO lights and other stuff, but only because over half their business is a nudge-nudge-wink-wink towards dope growers.

One thing I do agree with them about is these hydro guys tend to prefer linear lights over dense panels, and high powered linear LED growth lighting has only just recently been getting popular. Pretty sure Photowave was working on a product like this. I also build insanely high powered rails, but only for friends and legit purposes.

So, don't expect un-biased comments from hydroponics stores because they want to cater to their market which isn't exactly above ground. They sell products.

All of these panel type LED products discussed here are pretty much orientated towards dope growers, which explains their color ratio and tightly packed LEDs. Not exactly something that would work well on a row of houseplants against a wall or on your counter. Fluorescent fixtures do work better for this, and you don't have to worry too much about R/B ratios because a plant will take what it needs from a white light source. 

Otherwise, fluorescent lights sources aren't neary as efficienct as narrow band light sources like LEDs or HPS when it comes to growth radiation, and using 'lumens' as a measurement is bad because plants don't care about visual lumens or green light. Basic science, and we've bantered it in depth here and it's been proven by NASA research, etc. You could probably get away with half if not less energy used with LEDs than T5's to grow anything, but the difference between 30watts of fluorescent -vs- 15 watts of R/B LED just doesn't matter to most people. Plus, the purple glow of +20watts of R/B LEDs gets to be annoying after awhile. I did this over the winter with various houseplants and huge amounts of red light, and after awhile even my cats got sick of it. Plants however grew at insane rates. Faster than sunshine.

When it comes to big agriculture these guys use Metal halides and HPS, and that's pretty much it. Dope lights don't do it for them, and they are really skeptical of LED given it's rather narrow 'vocational use'. They do have a valid gripe, but for the wrong reasons. Blue light just isn't that critical a light source and comes from pretty much anywhere. Longer wavelengths required for fruiting, veggies and stem length are handled by 400 or 1,000watt HPS, and even though LEDs pump more energy at 630 or 670 nm, it's just not practical trying to replace that big a light source with red LEDs. If I were to design a green house from the ground up I'd certainly use low flying LED rails though, and my power bill would be less.


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## Oznog (Aug 11, 2010)

It depends on what "hydroponics" shop you go to!

I got the impression that the operators had "given it a shot" and the UFO stuff plain didn't work. It's a safe assumption that this was not lettuce or a corn plant, though. And Google shows that the ability to grow "that kind of plant" was highly disputable.

I also got the impression that they're normally happy to sell anything the customers want, but the LED stuff was so bad they just couldn't do it.

I think it's plausible that it could be effective, superior even, for some other plants. There's two factors there- one, the wavelengths it can effectively utilize through photosynthesis vary, the full-sun vs shade plants for one. But also the biological program of a plant seems to be tied to wavelength, and that's especially important for food crops you need to flower and fruit. 

So, its raw ability to photosynthesize wavelengths and grow and the WAY it grows and fruits are two different things. As such, I'm still seeing it as "complicated"- and results may vary widely with the type of plant used.


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## thepaan (Aug 11, 2010)

I can't actually see the auction because I'm at work but heres some pointers.

More important than the quality of the light is the quantity. HPS is actually some of the worst spectral quality you can give a plant but the volume of light is enormous. Plants adapt well enough to the the available wavelengths and thrive due to the abundance of it.

In a contained area (open areas allow the light to spread out more which requires more), you will need almost 300 watts in radiometric flux of red light (around 660 nm - other wavelengths require more) for one square meter to grow light-hungry plants such as tomatoes. I believe it would be generous to say an XP-E produces 0.5 watts radiometric flux while using 3 watts of power. This is 1/6th of the power used converted to light. Apply that to your 600W light and your looking at around 100 watts of radiometric flux, or .33 square meters of grow area.

Most plants only need two wavelengths. The most efficient for assimilating carbon dioxide is red, around 660 nm. The other is blue varying from 440 to 460 nm - which covers different responses having to do with how the plant shapes itself. Each response peaks at different blue wavelengths but they have a broad range of response and require minimal quantities - any blue light in the appropriate range ammounting to approximately 10% of the total light will do. Unless you plan to grow cucumbers then this light, having five wavelengths (one being IR?), is not as efficient as it could be.


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## Oznog (Aug 12, 2010)

Well, direct sunlight in southern latitudes, afternoon, summer-ish is usually approximated to be 1000W/m^2 (it's fairly accurate, and a round number).

Of that, a significant portion is useless IR or plant-damaging UV energy. In a white spectrum of light, you have portions of the spectrum which don't get utilized nearly as well as others.

LEDs are about 20% efficient. Some are more and some are less, and it depends on how you use them, but that number is "basically" a good rule-of-thumb. That's approximately the efficiency of CFL but significantly less than sodium or metal halide HID.

Sodium is much more efficient at creating light power but very yellowish, and has been observed to cause plants to grow much taller quickly, but it's actually bad- the plants are thin and aren't as healthy, and the tall profile is harder to illuminate properly. In fact, they grow into the lights and get burned. MH is not yellow-white and grows plants properly. But again, it depends on the plant.

The window of opportunity seems to be in the red wavelength, ~670nm, which plants utilize much more effectively. So much better that the lower efficiency of LEDs will be overcome by the improved utilization; at least that's the theory.

Trying to use a WHITE spectrum LED is pointless compared to MH. The spectrum is not much better, the efficiency significantly lower, and the cost and heatsinking issues are much higher. 

CFL would give you a very similar efficiency and spectrum, no UV or IR, for 1/10th-1/20th the price. Heck, the grocery store here just had a sale for 2700K 900 lumen 13W CFLs for $0.88/each, no limit. Hard to compete with that.


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