Discussion of the pragmatic application of LED's

[sm0k4]

@OGmolton: forget about green. If you got white you are fine!

@sm0k4: Actually your drawing wouldn't work, his was right!

Hah, yeah, you are right. Guess I shouldn't have wake n baked and then tried to to circuits, haha. My bad. I removed my bad info. Thanks for catching that.

 

[sm0k4]

Interesting thread!

I've been sneaking into cree and rebel led datasheets for some time now so i'm obviously intrigued with this led thing.

What's the actual consensus on watage compared to HIDs and on light spectrum of led fixtures if any??

LED cannot match the intensity of HID, but you can achieve similar or better results watt for watt if you adjust growing styles. With optics on the LEDs to narrow the light down to 90 degrees will allow more penetration. Lower wattage HIDs (250-400W) can be beat by even lower wattage LED due to efficiency of the LEDs since we know the spectral output. The wavelengths widely used in DIY are 545nm, 570nm, cool white, 625nm, 660nm. Green and orange/yellow can be included in the cool white LEDs IMO. The spectral graph shows output in those ranges, the plants don't use a ton of green and yellow anyway.

 

[BrwnStickyThumb]

Thanks to both you guys for clarifying and then I guess confirming that info about different LED voltages.

I think the consensus is that comparing led wattage to HID wattage is apples to oranges.

Me personally, I say anywhere you see a comparison of LED to HID, I wouldn't just disregard it, I would be suspicious of what they are selling all together.

I meant like how many led power do you have to use to match a 400w hps (for example). I know about light spectrum and light reflection of plants and understand leds are not like hid lighting but just trying to know if there was an actual simple comparation to start with, I've read 75% somewhere. In the end they're not that different they use electricity and both emit light....

LED cannot match the intensity of HID, but you can achieve similar or better results watt for watt if you adjust growing styles. With optics on the LEDs to narrow the light down to 90 degrees will allow more penetration. Lower wattage HIDs (250-400W) can be beat by even lower wattage LED due to efficiency of the LEDs since we know the spectral output. The wavelengths widely used in DIY are 545nm, 570nm, cool white, 625nm, 660nm. Green and orange/yellow can be included in the cool white LEDs IMO. The spectral graph shows output in those ranges, the plants don't use a ton of green and yellow anyway.

That's what I really wanted, thanks mate!! So a 400w hps could be substituted with say 250w right spectrum led or is more led power needed??
Penetration is an issue too, Is it better to group together led chips to simulate a hid light or is better to make a board and use more separated less focused leds?? Been looking at aquarium pages and seen all kinds of designs, they lack red usually, don't know exactly why.
What about the rest of the white leds?? in the charts it appears you could obtain a rich spectrum mixing different whites even if green or yellow is not used they don't produce that much either.

 

[sm0k4]

I meant like how many led power do you have to use to match a 400w hps (for example). I know about light spectrum and light reflection of plants and understand leds are not like hid lighting but just trying to know if there was an actual simple comparation to start with, I've read 75% somewhere. In the end they're not that different they use electricity and both emit light....



That's what I really wanted, thanks mate!! So a 400w hps could be substituted with say 250w right spectrum led or is more led power needed??
Penetration is an issue too, Is it better to group together led chips to simulate a hid light or is better to make a board and use more separated less focused leds?? Been looking at aquarium pages and seen all kinds of designs, they lack red usually, don't know exactly why.
What about the rest of the white leds?? in the charts it appears you could obtain a rich spectrum mixing different whites even if green or yellow is not used they don't produce that much either.

I'd say 80% power or so would perform the same, maybe less in smaller wattage setups. A 150W LED array should equal a 250W HPS if done with good emitters and the right space. To match a 1000W HPS, you probably want 800W of LED though since as HID gets bigger, their efficiency gets better.

Coral doesn't need red, so the reefers use blue and white Crees. Cree XML is pretty expensive, but the best 1W white emitter out. Their XPE color bins are the best 1W emitters in 625 and 450nm. Osram GD+ 660nm hyper red is probably the best in that wavelength. Unless you want to get the LEDEngin 5W 660nm chips and under-drive them. I could see 150W of these LEDs in the right ratios beating out a 250W HPS in a 2'x2' or 2'x3' room.

I need to buy more materials, but I plan to replace my 250W HPS with 260W of LEDs. I have a few panels made and need to get them in there for side lighting, but eventually I will have 260W of high quality LEDs in a 2x3 chamber. Thats 43 watts per square foot in LED. Since it is tuned for max PPFD, the wattage needed in theory doesn't need to be as high as with HID. Getting around the lack of deep penetration is the only limiting factor. Using smaller LED panels for side lighting or the 60 - 90 degree lenses are available for that hurdle.

These are just my observations after experimenting a bit and reading up on LEDs for growing over the past few months. I don't think commercial lamps are there yet, so the only way to truly beat HID is to do it yourself or throw more money at it by buying small footprint expensive panels.

 

[Andyo]

which wave lengths

which wave lengths

Ive read through the posts on this thread twice ,still cant find any solid consensus on which wave lengths .
Just the fact they run much cooler than hid and last 100,000 hrs nails it for me for veg.
Ive held back for a long time hoping to see some really efficient and wave length specific leds for Diy.
A

 

[sm0k4]

Ive read through the posts on this thread twice ,still cant find any solid consensus on which wave lengths .
Just the fact they run much cooler than hid and last 100,000 hrs nails it for me for veg.
Ive held back for a long time hoping to see some really efficient and wave length specific leds for Diy.
A

Right now I am using 640-650nm royal blue LEDs, ~5800K cool whites, 625nm red, and 660nm deep red. Ratio of 70% red(half 625nm, half 660nm), 15% white, 15% blue. One could argue adding green in also for 70%, 10%, 10%, 10%. I chose to not use green since the cool whites do emit throughout the PAR range and should provide enough to supplement whatever green light the plant needs IMO.

You could throw some far red, around 720nm in there also and run it a little at lights on and a little after lights off. This supposedly induces faster flowering, but I haven't tried.

My initial test grow was a minor disappointment with the Osram GD+ 1W emitters due to the lack of penetration. If the light gets any further than a foot away, they stretch like mad. With that wide of a lens angle(170 degrees), they would be best used for side lighting or inner canopy lighting. Plants can get to within an inch without burning.

I decided to build my bigger light with the Cree and LEDEngin LEDs for a tighter lens angle (130 degrees) and a large selection of optical lenses if I want to use them for more penetration. Once I purchase all the parts I will be adding the panels to my flower chamber and starting a journal.

 

[alkalien]

I'm just using reds (630 and 660nm 1:1 ratio) and very few blues 450nm (Osram Royal Blue). Than I add few whites, just to make it easier to look at the plants while lights on. If you don't add green or white I find it hard to look at it and afterwards you feel blind because everything looks green. Some white and the problem is gone. If you got whites on your scheme I was told you don't really need blue and if you got blue, you don't really need whites.

I'm sad knna is no longer here, he used to do a lot of testing on that subject, search for his posts on the topic!

I can not say anything bad about the Osrams emitters, I got one huge plant under about 300W LEDs. I tried to spread the lights arround the plant.

Thats waht she looked like before flower. She is about 1m high and stretched to 1,2 to 1,3m. I got buds all arround the plant.

Next week I'll start a run for motherplants which I will link here.

I'm afraid I can't compare my results to other lamps, never gave them a try...

 

[sm0k4]

I'm sad knna is no longer here, he used to do a lot of testing on that subject, search for his posts on the topic!

I can not say anything bad about the Osrams emitters, I got one huge plant under about 300W LEDs. I tried to spread the lights arround the plant.

KNNA was always tinkering with new ratios, and I started learning all this from his posts here and at the Cure.

Osrams are bright indeed, but you have to keep them close to the plants, thats the only drawback. I figure I will use them for lighting the inner canopy. I had my array in a PC case so I couldn't light the side of the plant. The lower branches just stretched bad since they were 7-10 inches away. If I had more light for the sides it would have been better.

I moved everything into my bigger flower chamber now since I got my 250W HPS installed. Here is what I am working with at the moment. I will have another light bar to add soon once I get the time to build it. Eventually I want all LED in here.

 

[alkalien]

Sorry, sm0k4, didn't mean to tell YOU to search his old posts, I read the conversations and followed your experiments well enough to know you did. I should have made clear, that everybody trying to get the basic knowlegde has to read his posts. Since he is gone the few other LED-DIY-guys here lost a valuable source of information.

I know you are ahead of both my experience and research...

I'm mainly focussing on the Osrams because I know where to get them and they are easy to mount. What makes me curious is, that Osram just launched a new set of LEDs for horticulture and claims that they are even better because of their wider angle.

I found out you can let your plants allmost grow into the light. I keep them about 10 to 15cm away.

I'll redo my setup for the next run and then post a few pictures...

 

[budlover123]

...Just the fact they run much cooler than hid and last 100,000 hrs nails it for me for veg...
A

They only last 100,000 hours if they are running at 1 watt, or 350mA. My Led light barely gets hot running at 1 watt, no fans or anything. Most commercial grow lights have good cooling with fans and everything, which tells me that they are about all running Leds over 1 watt.

That's fine to run them hotter with adequate cooling, my concern is are these Leds any good in the first place, or are these mediocre lights priced like good lights.

There's really no way to know because the info isn't supplied by the people that have it, they prefer to give us flashy nonsense.

 

[yesum]

Sad to hear about knna, he helped me a lot in pm's and on this and other forums. He liked to use a lot of white and not big on blue as the white provided enough of that. Along with other colors. He was going to set me up with a red and white LED unit, just 2 colors for veg thru flower.

I think the LED's with 60-90 degree lenses do have penetration equal to hid. The 3 watt narrow lens models of today have to be kept off the plants some to prevent bleaching and stunting in veg. Even my 1 watt 60 degree units are intense at close range.

 

[MPL]

This thread is amazing. Hopefully by the end of the year I will have a couple of LED harvests under my belt and can add my experiences to the pool of knowledge here.

/subscribed

 

[MPL]

I can answer this, though I'm not sure if it is appropriate to do so in this thread. If not feel free to delete my post.

The reason you primarily see blue in aquariums is because red light doesn't penetrate water very far. The creatures reef keepers are interested in also don't use red light. In fact, red light causes detrimental algae blooms and allows other nasties to grow.

If you think lighting a terra-based plant grow is complex you should look into providing light for corals...

Been looking at aquarium pages and seen all kinds of designs, they lack red usually, don't know exactly why.

 

[303hydro]

Also, I have found yields are much higher in a hydroponics set-up as opposed to soil when using LED lights. Usually this is true for HPS growing as well (in most cases) but have I seen a marked difference in budding when growing under LED. Soil plants did okay nothing great but not bad either. But in a hydroponic drip system in a coir & hydroton mix the plants really took off and grew massive towers of dense high calyx to leaf ratio flowers. The plants in soil as expected were far more leafy and yielder far less actual dried bud.

What would you say the ball park loss % of yield was soil vs hydro under the LED? I assume you were using co2 as well? I appreciate the info soft, your opinion is valued for sure.

 

[blimblom]

@sm0K4 , if you see the spectrum of white LEDs, the green they emit is arguably less than the normal sun white. Green spectrum, in white LEDs is only around 30-40% of blue and red emmited.

So in reality I dont think we use much green in our LED systems, for better or worse.

 

[blimblom]

I have another question regarding leds.

It seems I havent really find a nice watering schedule. with CFLs I was watering every 3rd day. But now with LEDs , Im not sure. Any guide??

 

[grow101]

You should be able to keep that schedule or use the same sense you figured out the 3 day rule with.

 

[LetsSeeYa]

I have another question regarding leds.

It seems I havent really find a nice watering schedule. with CFLs I was watering every 3rd day. But now with LEDs , Im not sure. Any guide??

Me too, but i found that the heat is not as bad with the LED's so i can water every 3 to 4 days. But it depends on the plant too. I noticed that when they get some good roots under them and start to veg out good, you might find they need more water for rapid growth. But its all in learning my friend, which makes the LED'S even more fun

LSY

 

[blimblom]

Long time with no news on the thread, but look what I found on the cutter.au site

http://www.theledstore.com.au/product_p/ls0017.htm

its a led array specifically tuned to plant growth AND it connects with molex connectors for those who cannot stand the soldering process..

I cannot tell how good or cheap they are (or not), because they dont have much data, but they have ready made series of growing and flowering combinations as you can see on the datasheet and they probably use the elusive 660nm reds

they claim 8,2-8,7 μmol/s Photosynthetic Photon Flux

check them out. I have my own setup and Imnot planning on changing it soon (its only a few months that I have it), but for new setups it may be quite good actually.

 

[Weezard]

Good information here.

Good information here.

Those look slick.
Can't wait to see someone do a side by side grow with them.

Yup, I know it's an old post.
I'm jus' here to BUMP!
This thread has valuable information for LED growers.

Prolly come back in a while to re-bump if need be.

Aloha, Y'all

Weeze