Cheap LEDs from China

[yoss33]

Hi there

First, I'm not much into indoor lighting - I need it only for starting the seeds before transplanting them outdoors. So, I've used only common cfls which are all fine for the first 2-3 weeks.
But lately I try to let the plants veg for a while before bringing them outdoors, so I was thinking of upgrading the cfls for faster growth and to make the light closer to the sun's strength, so that the plants get less transplant shock.
I could buy a MH lamp, but I've been curious about the LED technology and read some inspiring threads here! People are using mainly arrays of reds and blues. I guess this is most power-effective, but I saw that there are some quite cheap Chinese LED emiters, which are arrays of densely packed diodes, glowing in white. Didn't really find anyone trying anything like that, so I decided to give these a try, out of curiosity.
So, I bought a LED emiter Prime 100W 8000lm 6000-6500K, and a driver for it. Price was about $90 total, I saw even cheaper offerings at ebay. Here it is, mounted to an old heatsink+fan of an Intel processor:

I know it's not the most power-efficient at 80lm/W, but it's fairly easy to use, no need to install many diodes and do wiring.
With the 100W of diodes packed into 2.5 x 2.5 cm, it produces a VERY bright light, even from aside it's impossible to look at it. Blindingly bright, just as the sun.

Color is bluish white but doesn't feel sterile cold like fluoros. Colors around are not lost, meaning that the light is fairly distributed over the specter, not into tiny bands. Here's a photo made under the light on the emiter behind a white sheet of paper, colors are well preserved:

I will start using this emiter in the beginning of April and will let you know how it "grows"

 

[sso]

bought a 400w mh, german made,new, for 90$ , came with a bulb too..

still prefer vegging under my hps, faster growth, sturdier stem, less leaves but bigger. (600hps though)

but the mh is oh i forget, 28-36000 lumens, and covers up to 3x3 area.


i think those leds, might become interesting in 10 years, but i wouldnt bet on it.

though´d be somewhat interesting to hear how plants grow under that led light of yours and how many you can fit and how big they can grow.

 

[GP73LPC]

very interesting, thanks ...

 

[S-V-K]

Good luck.
I'm using chinese Leds and my plant is not growing what so ever.

 

[T_B_M]

Get a red one also for faster growth rates. I used a couple small cool white floros to veg with and noticed slower growth rates until I added an LED array of reds and whites. Now they take off once they root.

I highly doubt that light takes 100W either. If you have a DMM, you should take a voltage measurement across the input leads, then a current measurement in line with the V+ line, then figure out your power used by multiplying the current and voltage.

The main reason people growing with LED don't use a small package like that with many LEDs bunched together is for efficiency and heat reasons. LEDs don't emit light like an HPS, so spreading out the many sources of light over the grow area is the most efficient way. For clones or small seedlings that should be OK though as long as the light doesn't get more than 6" away from the tops. That will limit your coverage area also. Keep some growth updates here. I'm interested to see how it does.

These would be the way to go if you want to go modular.

 

[yoss33]

Get a red one also for faster growth rates. I used a couple small cool white floros to veg with and noticed slower growth rates until I added an LED array of reds and whites. Now they take off once they root.
...

Hey there
I'm sure the adding of 8000lm will help the growth rate over my 3 x 23W cfls Next year perhaps I'll add something more and see the difference.

...
I highly doubt that light takes 100W either. If you have a DMM, you should take a voltage measurement across the input leads, then a current measurement in line with the V+ line, then figure out your power used by multiplying the current and voltage.
...

I'll take the measurements this evening when I get home but I see no reason to doubt the specifications - 3A, 32-36V.

...
LEDs don't emit light like an HPS, so spreading out the many sources of light over the grow area is the most efficient way.
...

I've seen this statement but I don't quite get the logic. What makes diodes so different and what's the advantage of having 400 light sources instead of 4? Other than cooling I see no reason not to stack diodes. Its good to have several distributed light sources, so that the top fan leaves don't steal all the light, but hundreds of sources?

...
For clones or small seedlings that should be OK though as long as the light doesn't get more than 6" away from the tops. That will limit your coverage area also. Keep some growth updates here. I'm interested to see how it does.

These would be the way to go if you want to go modular.

If you are suggesting that I use this emitter 6" away from plants, it seems you don't realize how bright it is 6" is a ridiculous distance, it makes my hand hot in no time and would deliver most of the 8000lm to an area of about 150 square inches... what's the point?

 

[Phaeton]

I have a similar unit, 16 cells instead of 100. I use it as a trouble light, the 180 degree beam puts bright light everywhere, much better than a CFL trouble light.
The light is blue, then fades down the spectrum but does have some red. Being made for humans it is predominately green for brightness.

Same thinking, wow, what a bright little light. That 180 degree spread kills it though, the light diffuses so fast it has to be right on top of the clone, and $90 per clone for light is way too much for me. Although the one you pictured is 6 times as bright as mine it still spreads quickly and cannot be used for 3 x 3 clone area. No reflector leaves the light very center weighted.
This from a guy that uses one 336X-PRO per plant in the budroom, not cost efficient there either, so it really is all up to the individual grower as to what is best.

These SMD units will work, VisionX is where I got mine, already assembled with heat sink and driver. I hate to solder.

 

[T_B_M]

I am not explaining what is already widespread on LED technology for growing. They just can't penetrate like an HPS so the effect of inverse square law comes into play sooner. So the best way to use them is in a SoG type grow with many sources of light spread out above the canopy. With that light at 1 foot away what is the foot print? I wouldn't go any more than a foot, especially if the beam angle is wider than 90 degrees. Most times I keep my 120 degree LEDs 2-3" from the tops. Not sure what each emitter in your array is outputting, but I bet its not much different that my single LEDs.

Different LEDs can be treated differently also. I'm not sure what the beam angle is on that light, but at 120 degrees, my 1-3W LEDs don't have quite the penetration. I still get many 6" colas though because I train my plants out. For only vegging you should be OK, but adding some red will help the growth rates, especially is the dominant hue of your white LED is blue. Red induces some stretch and better growth rates. Too much blue and you get a plant that grows slow and doesn't branch out very fast. I know because I've done it and learned from my silly mistake.

The light is really bright, but what is the main active wavelength? Yellow? Green? Plants don't care how bright a light is, they care about its PPFD. If I were you, I would have gotten 2 cool whites and 2 warm whites to get some balance in spectrum at minimum. White has a lot of unusable light for plants. They are usually supplementary, not the main light source.

 

[yoss33]

I bought this emitter for fun and out of curiosity, and I don't really care how well it will perform as a grow light, as anyways afterwards the sun will have enough time to do its work
My growing space is 60cm x 60cm and these 8000lm if not enough will definitely be more than the 4500lm of cfls without reflectors that I used the previous 2 years.

I am not explaining what is already widespread on LED technology for growing. They just can't penetrate like an HPS so the effect of inverse square law comes into play sooner.

While I'm no expert in lighting, only using my common engineering knowledge, I see a lot of widespread misunderstandings on these forum. Like your statement above which sounds like common sense but is ridiculous if you know what stands by the words used. Please, don't read only marketing papers.
I guess talking about "effect of inverse square law" sounds cool, but unfortunately the inverse square law has nothing to do with the type of light, or with the type of wave in general. It is always valid for all point-source wavefronts in 3D space, at all distances. It is always "into play", no "coming into" and no half-working. Reflectors change the geometry of light, and the wavefront is not a part of a growing sphere, so the inverse square law is not applicable here. But reflectors can be used with all types of light sources, so reflectors' effects are not an argument for/against HPS/LED/etc. After all, all reflectors do is help in directing more of the light towards usable area.
I see this mantra about HPS/MH having higher "penetration" at many places, but this sounds plain fetish , without physical explanation anywhere. As if HPS's photons are different - somewhat "heavier" and "penetrate" deeper You say your "1-3W LEDs don't have quite the penetration" comparing 1-3W with 400W. Sure they don't. But what about 400W of LEDs stacked into an almost point source? You think it will not "penetrate"?

 

[Rinse]

How hot are led's compared to cfl's? How close to plants is recommended? Cheers.

 

[yoss33]

This LED emitter seems to work fine, at least for what I need it for - seedlings.
Here's the progress for one week - from 1st of April till today:

Today:


The tops of the 2 plants are 32cm (i.e. about 1 foot) away from the emitter.

 

[yoss33]

In my quick setup, the fan is blowing downwards through the diode and the warm air is blown directly onto the top leaves. And so, at 20cm away from the diode the indica plant's leaves started to curl and get bleached segments. So I transplanted the plants outdoors and am left with only the small cup on the last photo from my last post. It now looks like this:

Good progress for the last 20 days, considering that 10 of these were spent in a cup. The light is now switched to 12/12.

 

[yoss33]

Btw, here are the 2 bigger plants, just before transplanting them outdoors 6 days ago, they were exactly one-month old from sprouting. Could have grown bigger if not in cups for more than 2 weeks.

 

[oneshot]

Thats incredible.

 

[OBK]

Very, very cool. This could give micro grow a whole new dimension.

 

[lunatick]

That's an impressive growth rate.

The light is now switched to 12/12

are u gonna flower with that led?

i would love to see a high power warm white smd led/s in flower.

 

[yoss33]

Yes, I'm going to flower that pot.
I haven't grown these seeds before, so I can't compare the progress to the same strain under different setup. The seeds in this pot are sativa-dominant hybrid, so should be vigorous plants.
The pot itself is quite small, the plants are root-bound, but I'm more interested in what's their high, so I'm not going for max yield, I only need a few joints of each plant. I guess I won't even bother transplanting into a bigger pot for the flowering. I only hope that the PH doesn't drift too much in this small container of soil. So far, so good.

 

[trem0lo]

I'd love to see a whole grow using this light. What a fab solution for a micro grow.

 

[yoss33]

A quick update.
At day 5 of 12/12 I got impatient and the lighting cycle was switched to 10/14. The plants made a mighty stretch and the 2 taller plants touched the ceiling of the cardboard box. I didn't bother with training, I think they are fine enough that way There's some bleaching of the leaves close under the light and some leaf curling at the top, where the plants touch the ceiling of the box, where there's no ventilation and temperature is high.
The 2 bigger and taller plants are Thai x Oaxacan, the 2 smaller in the center are from the same Thai mother pollinated by local hemp or ruderalis or I don't know what. Some 25 days after turning the lights for flowering, we are here:


I hoped to have an early harvest somewhere around day 40, but it seems I'll have to wait more.

 

[lunatick]

nice,tnx for the update dude.

I got impatient and the lighting cycle was switched to 10/14

why is that?plants will flower *faster under 12/12.

"where there's no ventilation and temperature is high." - there is still time to fit a small fan

+light trap if needed in there.

im gonna try 2 20w *warm white(3000K)led emitters in a pc hopefully soon.