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DIY LED plant light project

  • #41
This debate has been going on for a while now with much more glister than gold. I've heard a lot of claims made in regards to LEDs. Quite frankly these claims smack of the hype used with compact fluorescent bulbs, and they were a bit of a bust when it came to a high end lighting solution--although I'm sure someone will disagree with that. As I am no expert on lighting, I would like to ask those who know better than myself, is there any scholarly consensus yet on the use of LED lighting for growing plants with high light needs, e.g., CPs, bell peppers, etc?
 
  • #42
Wes,

It seems there are very few black and white answers when it comes to needed wavelengths....
Earlier research by Gioia D. Massa et. al., for NASA's ALSS showed quite a bit of variability in the needs of plants.
Some performed well with no FR, others poorly.... while some other observations were not understood and still needed further research.
(20% seemed to be a good metric for blue)

In some experiements CWF's seemed to provide benefits that were not achieved using RGB LED's.... which seemingly were still missing something or maybe were of the wrong balance.

I'm anxious to see your research when it becomes available, plant lighting has been one of my fav areas of interest for quite a while.

I also look forward to playing with my new Tristar when it arrives :)
(I ordered this heatsink/fan for it)
 
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  • #43
As I am no expert on lighting, I would like to ask those who know better than myself, is there any scholarly consensus yet on the use of LED lighting for growing plants with high light needs, e.g., CPs, bell peppers, etc?
I am no expert either, but I am an experimenter. I have been tinkering with lamps for growing plants for many years. The primary advantage of white LEDs over linear flourescents, in my opinion, is that they are easier to direct/focus. The exact spectrum that they output is dependant on the phospors used, in the same way as flourescent lamps.

But, the main reason for using LEDs over flourescents would be to increase efficiency by selecting the specific wavelengths required for plant growth and thus eliminated the waste light that plants cannot use. I have experimented with white LED but now just use them as supplimentary, rather than primary light sources. For the primary I use wavelength specific LEDs, such as reds and blues that have wavelengths as close to the chlorophyll absorbtion bands as possible.

As for whether they are suitable for CPs, one of my experiments is with growing U. campbelliana under a LED grow lamp, consisting or red, blue, amber and white LEDs. This species likes lots of light but not much heat, so LEDs are ideal for this and it grows very well.
 
  • #44
Herm, one of my colleagues is currently working with tomatoes and high output LEDs. The problem they have been running into with the high output LEDs is that they must be actively cooled which ends up requiring more energy than is saved by using the LEDs. I think the current goal is to see whether or not plants that need high light can be suitably grown with LEDs. The next step would be to develop more efficient cooling (be it active or passive).

Butch, yea, we've gotten some very species specific results as well which isn't really a good thing because no greenhouse manager wants to have to adjust their lights according to species. My goal is to find a mix of R/B that is suitable but not necessarily for all species across the board. We are specifically comparing it to HPS the current industry standard. But yea, black and white RARELY happens in the real world.

Mobile, yup, that's why people are really watching LED research. Since they can be tailored to a very specific wavelength we can develop lights that are optimal for plant use. Additionally, LEDs are nice because they dont waste most of their energy in heat loss. So, yes they generally stay cooler which for some species is actually a bad thing. Think Celosia.
 
  • #45
i was wondering if it is possible to use something like a liquid CPU or RAM cooler, like this one, http://www.frozencpu.com/products/1...DR2DDR3_-_14_ID_8mm.html?tl=g30c225s557#blank to cool some Tristar LEDs. things like this are sometimes used in high end/gaming computers, and i figure that if they can handle the type of heat lhat CPUs, GPUs, etc, etc, generate, then they would also be perfect for cooling LEDs.

any suggestions as to how i could go about doing this?
 
  • #46
i was wondering if it is possible to use something like a liquid CPU or RAM cooler, like this one, http://www.frozencpu.com/products/1...DR2DDR3_-_14_ID_8mm.html?tl=g30c225s557#blank to cool some Tristar LEDs. things like this are sometimes used in high end/gaming computers, and i figure that if they can handle the type of heat lhat CPUs, GPUs, etc, etc, generate, then they would also be perfect for cooling LEDs.

any suggestions as to how i could go about doing this?
Heatsink performance is measured in °C/W, which the above does not appear to specify in the link. Without this, it would be impossible to say whether it is suitable for LED cooling. Personally, I tend to use active cooling, e.g. with a fan cooled heatsink.
 
  • #47
Personally, I tend to use active cooling...

isnt liquid cooling a type of active cooling?if you wanted to use that thingy above, to cool RAM chips, LEDs, or really anything else that needs cooling, then you wouldnt just use it passively. it would be attached to a reservoir, pump, and a radiator. water would flow through the device, taking heat away from the chip.

Heatsink performance is measured in °C/W, which the above does not appear to specify in the link. Without this, it would be impossible to say whether it is suitable for LED cooling.

that is just one of many heatsinks/water blocks available fom the site, and that is only one in who-knows-how-many other sites on the web that sells this sort of thing, so there is probably some water computer cooling device out there some where that would be suitable to re-purpose for coolin' high-power LEDs

oh, and the particular cooling device i posted a link to above is intended for RAM chips which are shaped like a long-ish rectangle, so i thought that if it could cool them properly, then i could put a couple of LEDs in a row along it, to make a kind of LED strip-light. if i wanted a longer strip , then i could just put together a few more, and arrange them end to end.

another idea i had would be to use a bunch of CPU water blocks (which are usually square, like ordinary CPU heatsinks) , and have each one cooling a single tri, or even quad LED, and position them over the plants. then i would just connect them all together with tubing, and attatch the whole thing to a reservoir, pump and radiator.

i got the idea to use some kind of water cooling system because i wold rather use tri, quad, or other multi-LEDs so that i wouldnt have to worry as much about color blending. these kinds of LEDs throw off a lot of heat, and these type of cooling systems are used to cool CPUs, some of which can get pretty darn hot, about as hot (probably hotter) than these LEDs, so it seemed like something that might be a good way to keep the lights cool. i take it that no one on here has tried this? might be worth a shot, ya never know 'till ya try...
 
  • #48
If you do leds, order from stevesleds.com. They use rebel leds and offer customization for dirt cheap. A tristar is $12 with RB, NW, and DR.
As for cooling, from what I know from reef leds, a regular heatsink should be fin as long as a fan is there as well. Steves actually sells nice fans and heatsinks.
And CPU coolers work great because they are made for moving heat away from a small area, like with leds, but again, an extruded heatsink with fans works good.
 
  • #49
It would work to use a CPU fan, liquid cooling or a combination. The problem you will run into there is that you might as well switch to fluorescent lights because you won't save enough energy with LEDs+active cooling to make the switch worth it (unless your goal is specific light wavelengths). Any number of tests that we've done with active cooling usually any energy saved with the LEDs themselves. Cooling fans (CPU, GPU, RAM, PSU, etc.) are why desktops are such huge power suckers. If you are not trying to supplement sunlight I'd recommend using block heatsinks because they should work just fine and there wouldn't be a concern over blocking precious sunlight.
 
  • #50
I never though using forced cooling was very endothermic. If you use a couple 12v fans over an extruded heatsink, The total power usage of the fans should only be about 6w.
Maybe it's different with cpu coolers.
 
  • #51
I typically find that I only need a small wattage fan. What I don't know though is the efficiency of LED Vs. fluorescent lamps. If they are close then a fan could tip the balance.

The theory is that LEDs should be more efficient plant light sources than white light sources, if the correct wavelengths can be identified and provided, as white light light sources potentially produce wavelengths that plants can't use - thus wasted energy.
 
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  • #52
LED's are actually rather electrically inefficient at approx 40% radian efficiency. This inefficiency is obvious in the heat they generate and the cooling they require to live.

Their big advantage to me personally is while T5's need to run hot for top efficiency; LED's are just the opposite, they need to run cool.

So if you are trying to build a setup for HL or UHL, LED's bring a big advantage to the design. They may indeed lose out in electrical efficiency compared to other forms of lighting. However, their ability to do it while being kept cool is a major advantage imho.

Mobile comments are also very true.... energy not being used in unneeded wavelengths is an inherent increase in efficiency.

Just a caveat, I looked at stevesleds.com and while cheaper.. it appears they are an older model (now discontinued by mfg.) as compared to those being sold by luxeonstar.com
(Stevesleds.com carries the Rebel SE models with what looks like the "Saber" tristar mount)

Of course they are almost half the price of Luxeonstar....just something to be aware of when making comparisons

Av
 
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  • #53
So if you are trying to build a setup for HL or UHL, LED's bring a big advantage to the discussion. They may indeed lose out in electrical efficiency compared to other forms of lighting. However, their ability to do it while being kept cool is a major advantage imho.
Av
And that's something I'm using to my advantage with my U. campbelliana setup. It would be extremely difficult to direct as much light at this plant using anything other than LED lighting. In fact, one of the successful EU campbelliana growers uses metal halides for his plants and keeps the plants in a fridge, with the light shining though a window at the top. With my setup, using LEDs, I need no cooling for the plants.
 
  • #54
And that's something I'm using to my advantage with my U. campbelliana setup. It would be extremely difficult to direct as much light at this plant using anything other than LED lighting. In fact, one of the successful EU campbelliana growers uses metal halides for his plants and keeps the plants in a fridge, with the light shining though a window at the top. With my setup, using LEDs, I need no cooling for the plants.

Wow! Growing plants in the fridge to counteract the HID? That is pretty amusing. I'd hate to see that power bill too! LOL
 
  • #55
Wow! Growing plants in the fridge to counteract the HID? That is pretty amusing. I'd hate to see that power bill too! LOL
FYI - he may have needed the frig with or without the light since campby's can be picky about temps & definitely likes things on the cool side.
 
  • #56
If I'm thinking of the right set up, there are also a few other picky HL only species in the fridge as well.
 
  • #57
So far the initial test subject is responding very well....
Growth rate and dew production has been impressive.
IMG_4624_hf.jpg

You can definitely see the abundance of blue/red in the mix.

Looking directly at the tristar causes headaches.... lol, owie.
Will update from time to time...
 
  • #58
Butch! A dew! I'm so proud :awesome:

Looks good for LED. What species is it?
 
  • #59
ummmm the one that was recently in quesiton... utra ultra or u-someghing

whatta you mean :p
 
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  • #60
Ah yes ultrawhatever. That one!

I know, I know, I've seen the pics of your SA dews. I'm just givin you a hard time cause I think you should grow more!:-O
 
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