# Are most LED grow lights a ripoff? Why do they need so many LED's?



## HighlanderNorth (Sep 21, 2011)

I have used a 400 MH grow light fixture to keep my tropical plants like tangerine, grapefruit, and Pomegranate trees alive in winter, because I dont have a sunny window.
I also had to supplement it with other fluorescent fixtures and a couple incandescent single bulb fixtures as well, and I still didnt get the light I needed in winter, and most trees lost their leaves. But when I put them back outside in summer, they grow their leaves back, but it still isnt good for them to go through this every year. 

Plus, the 400w MH fixture generates MUCH heat, and all the lights put together generate about 700w and run at least 12 hours per day, which still doesnt work well.

I dont have the citrus trees anymore, but I learned that pepper plants are perennials, 
so I will be bringing in 1 Jalapeno plant, 2 Poblano/Ancho plants, and 3 bell peppers this winter, along with my Pomegranate. The peppers will just keep getting bigger each year after being brought outside in spring-fall to flower and produce peppers each season again.

The LED grow lights have LOTS of LEDs, and I understand that they need a mix of red and blue light for vegetative growth, and red for flowering. Well, I only need the type for vegetative growth. But even though they might need a mix of different color lights, they still dont need so many bulbs........

Many have over 225 LEDs built in. So why dont they use higher wattage LEDs so they can use less total LEDs and make the fixture smaller? I'm wondering if the quality and power of the LEDs in these grow lights is low and weak?

I cant seem to find the brand name of the LEDs they are using in many of their advertisements either, so I wonder if they arent using low quality, low power LEDs, but still charging a high price, like $229-$600?

Anyone know anything about them? They claim to be as powerful as MH or HPS lights, or more, while using the same wattage........ But is it true?


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## Inkidu (Sep 21, 2011)

Most led commercial units aren't that good in my opinion. Most claims are bogus. 
A short answer is that led are just to expensive.
VHO fluorescent lighting has come a long way if heat is a problem. 
They are actually starting to replace MH bulbs in commercial buildings for lighting.
If you look hard enough you can find "grow" bulbs that aren't super expensive.
And with a good reflector a T5 can be aimed fairly well. 
Search "led grow lights" here and you will find some threads on the subject.

Hope this helps.


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## blasterman (Sep 21, 2011)

> So why dont they use higher wattage LEDs so they can use less total LEDs and make the fixture smaller?


 
Because they are built to maximize profit and take advantage of cheap labor soldering all those tiny, inefficient LEDs onto terrible heat sinks. You have a wallet, and somebody wants what's in it. I can't get more blunt than this. If you want more state of the art fixtures you'll need to look at those used for reefing, and even the majority of those are junk. The Cree based ones are very expensive.

For my own growth lights I use new XP-Es and drive them at an amp. Not sure how many 5mm or 10mm or SEMI based LEDs they kick in the pants, but it's likely a heck of a lot lot. 30watts of royal blue XP-E likely has the same blue growth energy (PAR) as 100-150watts of metal halide. Daylight balanced MH wastes huge amounts of energy emitting green and yellow which is why they are so hot and bright but don't do much for plants.


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## Inkidu (Sep 22, 2011)

blasterman what do you think of the Cree XT-E royal blues?
I only just notice them are they that new?
They are kind of cheap in bulk i.e. $2.54 each when you buy 10 or more. 

http://www.cree.com/products/pdf/XLampXT-E_ROY.pdf

Thanks for any help.


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## deadrx7conv (Sep 22, 2011)

The XT-E's are relatively new. Being royal blue, its worth a shot since they're 20% more efficient than the XP-E's. Just make sure you get them MCPCB mounted, or are familiar with soldering/flowing LEDs.


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## blasterman (Sep 22, 2011)

If they are indeed 20% over top bin XP-Es in royal blue then they are a lot of fire-power for the money. Mounted on stars should put the price no higher than $4.00. With the lower Vf you can get them on triple stars with no heat problems and gain some pretty impressive energy density.

Doing the math, a single triple star XT-E at an amp will throw more blue PAR than some of the smaller $200 beehive growth lamps I've seen listed. :thumbsup:

Used to be that cheap red and blue LEDs (Satistronics, etc) would give you a better dollar per lumen ratio. If you wanted maximum efficiency you went top bin Cree or Rebel (add a couple others to this list), but you paid a lot more to hit the same energy levels. However, as blue and red efficiency levels have increased and prices have dropped with the big boys it no longer makes sense to use the cheaper LEDs for DIY - unless you have a factory in Asia and want to make maximum $$$.


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## SemiMan (Sep 22, 2011)

HighlanderNorth said:


> I have used a 400 MH grow light fixture to keep my tropical plants like tangerine, grapefruit, and Pomegranate trees alive in winter, because I dont have a sunny window.
> I also had to supplement it with other fluorescent fixtures and a couple incandescent single bulb fixtures as well, and I still didnt get the light I needed in winter, and most trees lost their leaves. But when I put them back outside in summer, they grow their leaves back, but it still isnt good for them to go through this every year.
> 
> Plus, the 400w MH fixture generates MUCH heat, and all the lights put together generate about 700w and run at least 12 hours per day, which still doesnt work well.
> ...



Why a LED grow light ... I mean a good LED grow light:

A) Much more efficient than any MH or Flourescent for growing, and yes even better than HPS for growing. Think 2x+ in the latest generation of LEDs.

B) You don't fry your plants.

C) They grow faster.

Semiman


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## bshanahan14rulz (Sep 22, 2011)

My guess is that the more emitting area you have and the more spread out it is, the more likely it is to illuminate a higher percentage of the green foliage. I don't know if the goal is to light up the entire surface area of a plant, but I don't see why it wouldn't make it grow better.


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## Harold_B (Sep 22, 2011)

Lots (and lots) of information to be had and here's a great place to start: http://sevengens.com/

These folks came together on LinkedIn with a common interest in LED grow lights and have pooled their knowledge and resources. Not necessarily cheap but a well researched home built lamp.

I'm planning to build a few.


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## blasterman (Sep 22, 2011)

> My guess is that the more emitting area you have and the more spread out it is,


 
Good train of thought, but you can spread out higher powered LED's easier than a larger amount of smaller ones. Super easy to mount 3watt LED's inside aluminum U-channel and have several square feet of coverage -vs- a beehive panel that's 12x12".

This stuff is dirt simple to build, and costs less than the commercial panels at the same power levels.


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## x101xtreme (Sep 24, 2011)

Speaking of LED grow lights, I just finished building my own light several weeks ago. The current grow area is 2x2ft. I haven't tried flowering any plants under LEDs yet, but the plants look healthy during their vegging phase. With LED grow lights, DIY is the way to go if you know which wavelengths you want.I've been keeping them on for 18 hours a day. The leds are being driven by 2 constant current drivers. One single 1400mA driver for the reds in a 3S/2P configuration and a 2100mA driver for the blues in a 2S/2P configuration.

LEDs Used and Drive Currents:
12 Cree XP-E Royal Blue LEDs at 1.1Amp Each
12 Cree XP-E Red LEDs at 700mA Each
6 Luxeon Rebel Deep Red Leds at 700mA Each

Power Consumption: ~80W

Total Cost: ~$300
I basically mounted everything to a metal panel with arctic alumina and soldered the LEDs in series/parallel configurations. With a 150W 24V DC power supply, they seem to be performing very well for herbs. A vertical fan was used to pass air over the heatsinks and keep the whole setup cool.

Here Are Some Pictures




























And Here is the Grow Log with a New Pot of Basil

9/8/2011





9/12/2011





9/15/2011





9/16/2011





9/19/2011





9/22/2011





9/24/2011


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## IMSabbel (Sep 25, 2011)

deadrx7conv said:


> The XT-E's are relatively new. Being royal blue, its worth a shot since they're 20% more efficient than the XP-E's. Just make sure you get them MCPCB mounted, or are familiar with soldering/flowing LEDs.


 
Well, looking at the specs, they have 500mW of radient output at 350mA typical (medium bin).

The Vf at that current is about 2.85V -> they have ca 50% electrical efficiency on average.

I do not recall the old XP-Es to be anywhere close to that.


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## Oznog (Sep 26, 2011)

It depends on your goals.
LEDs won't be cheaper than MH. That stuff is VERY efficient, and it can probably make some gains, but not remarkable gains. It'd be hard to justify the power savings of a well-designed system versus the purchase cost.

If you're building a moon base, or want to grow food plants indoors in Alaska with absolute minimum power regardless of cost, or just prove it can be done, then YES, it works!

There's been some questions as to whether the LED spectrum is more efficient for producing photosynthesis. Search the forums for prior discussion.

The light distribution efficiency is a HUGE issue. I mean, you'd be wondering "hey, I might be able to get 20% more lumens/W with an LED"- but look at the distribution- like only 1/3 of the projected light even hits a leaf! Optics would help, but optics also have losses. The mylar reflective stuff isn't that good at recapturing light- it's of some additional value, but each reflection loses like 10% of the light energy, and statistically speaking most photons will probably either strike something else or go through many bounces and get lost before reaching a chloroplast.

One thing, though- LEDs can be set up to extract the heat very well out of the grow area. Like an MH, they're of similar efficiency, but you can't heatsink a MH, they reject all their waste heat into the grow area. There are some weird systems to put a water-cooling jacket around an MH to trap heat. But you can sink the back of LEDs and even insulate the side of the sink which faces the grow area, so the heat never gets into the grow area at all, only the light.

Yeah, the "swarms of little devices" aren't a good thing. Bad cooling, they probably use old, less efficient emitter tech, and lots of little ones are MUCH less reliable than a few powerful ones.


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## Oznog (Sep 26, 2011)

delete, double post


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## WeLight (Sep 26, 2011)

I bought some of these to grow tomatoes in a hydroponic setup and they are awesome
http://www.illumitex.com/horticulture-lighting.php

They are premixed colours so you dont need to mix discrete leds, 1 module replaces around 8-10 Cree leds as they have 16 die per module and have built in optics that are tuned to mix colours


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## blasterman (Sep 26, 2011)

> hey, I might be able to get 20% more lumens/W with an LED"- but look at the distribution- like only 1/3 of the projected light even hits a leaf! Optics would help, but optics also have losses.


 
Wide angle LED acrylic lenses have a fraction the efficiency issues that halides have with reflectors. Also, if coverage is an issue, use that thing called an opposable thumb and lower the light. Again, this is much more easily accomplished with LED's given the thermal issues involved with halide.

Last, daylight halides do not have near the blue or red efficiency that LED's have, especially when compared to premium flux LEDs. Where high wattage halides hold their own is visual lumen efficiency, but plants typically don't need green and yellow green light. Taking all these issues into account explains why solid state lighting hits a 1.5-3x power improvement over daylight halide for agricultural use.




> 1 module replaces around 8-10 Cree leds


 
Those 1/8watt Crees or XM-Ls? Also, are there spectral intensity graphs backing this up?


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## SciGuy (Sep 26, 2011)

Could you give an idea of the per module cost on these?

Thanks

Hugh


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## Garibaldi (Sep 26, 2011)

WeLight said:


> I bought some of these to grow tomatoes in a hydroponic setup and they are awesome


 
Uh, you bought your own lights from your own company and think they are awesome???!!! You are a shill posting SPAM in this forum and should now be blocked by the administrators!


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## WeLight (Sep 26, 2011)

Garibaldi said:


> Uh, you bought your own lights from your own company and think they are awesome???!!! You are a shill posting SPAM in this forum and should now be blocked by the administrators!



Sorry?? this is not my company, but I know the owner who is a friend, and I have not made any mention of where to purchase these!! So I am in the led business means I can no longer share information about my own experiences?


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## David_Campen (Sep 27, 2011)

Oznog said:


> ...The light distribution efficiency is a HUGE issue. I mean, you'd be wondering "hey, I might be able to get 20% more lumens/W with an LED"- but look at the distribution- like only 1/3 of the projected light even hits a leaf! Optics would help, but optics also have losses. The mylar reflective stuff isn't that good at recapturing light- it's of some additional value, but each reflection loses like 10% of the light energy, and statistically speaking most photons will probably either strike something else or go through many bounces and get lost before reaching a chloroplast. ...


I don't know why you say this. I am assembling some LED grow lights precisely because I can get efficient optics that will project a narrow spotlight to where I want it. I plan to use LedEngin optics that claim to be able to focus the light from their LZ4 LEDs to a 12 degree beam with 90% optical efficiency.
http://www.ledengin.com/files/products/lenses/LLNS-1T06-H.pdf


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## SemiMan (Sep 27, 2011)

Oznog said:


> It depends on your goals.
> LEDs won't be cheaper than MH. That stuff is VERY efficient, and it can probably make some gains, but not remarkable gains. It'd be hard to justify the power savings of a well-designed system versus the purchase cost.
> 
> If you're building a moon base, or want to grow food plants indoors in Alaska with absolute minimum power regardless of cost, or just prove it can be done, then YES, it works!
> ...




Current LEDs with the release of efficient deep reds have over twice the spectral efficiency for photosynthesis as MH and even HPS (good operations use both). They easily pay for themselves over the life of the LED when energy usage is taken into account.


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## chainrash (Sep 27, 2011)

x101xtreme said:


> The leds are being driven by 2 constant current drivers. One single 1400mA driver for the reds in a 3S/2P configuration and a 2100mA driver for the blues in a 2S/2P configuration.



Hey, Great post, thanks for the pics. I'm just starting to dabble with LEDs, so I have a few "newbie" questions.

1. Can you explain the wiring a little more? What do yo mean by 3S/2P? Is this how you drive the LEDs at 700mA from the 1400 and 2100 mA drivers?

2. Where did you get your supplies? I've searched a lot for "LED Grow Lights" and the like. Frankly I'm a little overwhelmed by the choices.

Thanks in advance for your help. Again, great post!


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## Inkidu (Sep 27, 2011)

3 led in series.
2 led in a parallel string.
Read this 

Hope this helps.


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## Kinnza (Sep 27, 2011)

Most LED grow lights out there are rip offs. Some are pure rubbish, some perform decently but price is usually excessive to be cost effective against any HID (MH, HPS, plasma).

The best way you can have one is build it yourself. Not only you decide what LEDs to use, so you know the efficiency of your system, but you can mount them in a way you get an homogeneous lighting on your plants. An structure with aluminium U bars (rectangular tubes if you prefer to use forced cooling) is all you need.

Those Ilumitex LEDs have good efficiency and are easy to mount, at decent price. However, is not easy to get a good color distribution. I've been looking at the spectral distribution of modules and in general they are too bluish for horticulture, especially for trees. There is need of mix some red modules for each blue/white one and given they arnt wide angle optical emitters, achieving a good color mixing and a good overall spectrum seems a little difficult.

Instead, I would use simple LED emitters, which allows to mix better the light. Currently, all you need to get a good horticultural spectrum valid for most growing stages is to mix red and white LEDs (or red and blue, but just for vegetative stage or leafy plants). 2:1 red to white up to 4:1 usually works very good. 3:1 is a good compromise that gets a good balanced spectrum.

For whites, Cree XP-G or XL-M, preferably neutral whites (coolwhites if you want higher efficiency and a bluer spectrum). For red, using both normal and deep reds usually works the best and is a little cheaper. For normal red, get whatever you got at the best price, provided a minimum of 50lm/W for 625nm dominant wavelength (Avago, Lumileds, Cree, Osram..., but there is many). For deep reds, you have the Rebel and the Golden Dragon Plus.

Efficiency of these LEDs drops noticeable past 700mA (except the XM-L, of course). In order to get good efficiency (photons emitted/input watts) able to offer electric saving against HIDs, you shouldn't run them over 700mA. And preferably, run them softer. 

Anyway, the main you should consider is how many watts you need to install. Dont try to use much less than half watts of you need of HID lighting for the same space. Usually half watts is a good guideline when using good LEDs. If the 400W MH showed to be short for lighting the grow area, probably it means you need to use more power. Say, 600W, so you need to look for a LED lamp about 300W of power. And that, still DIY, may be really expensive and difficult to be cheaper in the long run than HID lighting. Only if high temperature is really a problem going all LED lighting is advisable on a large grow area.

How large is the growing area? Are plants spaced or all together?

An interesting alternative is combine a cheap HID (HPS) with blue LEDs and some deep reds. That allows to reduce overall cost and control temperatures.


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## Kinnza (Sep 27, 2011)

David_Campen said:


> I don't know why you say this. I am assembling some LED grow lights precisely because I can get efficient optics that will project a narrow spotlight to where I want it. I plan to use LedEngin optics that claim to be able to focus the light from their LZ4 LEDs to a 12 degree beam with 90% optical efficiency.
> http://www.ledengin.com/files/products/lenses/LLNS-1T06-H.pdf


 
Are you going to place LEDs very high over plants? A 12º optic only makes sense if you need to project the light from a long distance of plants. And more with a powerful LED.

If you concentrate light so much, some parts of the plant get a lot of light, and they usually cant manage it, resulting in permanent photodamage (bleaching), while other parts dont have enough light. Spot lighting is one of the main things to avoid in plants lighting.


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## David_Campen (Sep 27, 2011)

Kinnza said:


> Are you going to place LEDs very high over plants? A 12º optic only makes sense if you need to project the light from a long distance of plants. And more with a powerful LED.
> 
> If you concentrate light so much, some parts of the plant get a lot of light, and they usually cant manage it, resulting in permanent photodamage (bleaching), while other parts dont have enough light. Spot lighting is one of the main things to avoid in plants lighting.



Yes, the LED fixtures will be mounted on open beams that are 9-12 ft. above the floor or at least 6-9 ft. away from the surface of the benches. At a distance of 9 ft. the 12 degree lens will illuminate an area of about 2 ft. in diameter. This is exactly the reason that I am using LEDs instead of t-5 fluorescent. 

Fluorescent or HPS would be a lot less expensive but can't be easily focused so these need to be placed close to the plant. I estimate that my LED lighting with fixtures will cost me about $4 per watt (of power into the LEDs).


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## Kinnza (Sep 28, 2011)

David_Campen said:


> Yes, the LED fixtures will be mounted on open beams that are 9-12 ft. above the floor or at least 6-9 ft. away from the surface of the benches. At a distance of 9 ft. the 12 degree lens will illuminate an area of about 2 ft. in diameter. This is exactly the reason that I am using LEDs instead of t-5 fluorescent.
> 
> Fluorescent or HPS would be a lot less expensive but can't be easily focused so these need to be placed close to the plant. I estimate that my LED lighting with fixtures will cost me about $4 per watt (of power into the LEDs).



In that case, it is right to use lenses. As you say, you can't focus effectively light from so long with other technologies, except with some plasma devices and R type halides. The other have very large optical losses when you try to focus them.

But it is a very special case. In general, lamps are placed as closer the plants as possible, reducing optical losses and allowing most light emitted hit plants. LEDs are hard and run cool enough to put them between plants (intracanopy lighting, or interlighting), which have the highest efficacy (Radiation Use Efficiency is near double for interlighting than for overhead lighting in plantophyle's species, and 30-50% more efficient for other types of leaves orientations). Check for example Philips's range of horticultural lamps: http://www.lighting.philips.co.uk/application_areas/horticultural/products.wpd, , all wide angle.


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## ChocHabanero (Sep 28, 2011)

Hello, I just registered here as this seems to be a place to get/share quality ideas without any particular bias that I've encountered elsewhere.

I started growing Chilli plants in a Greenhouse this year (partly becuase I love Chillis and partly becuase I sometimes take up random new hobbies). In the UK we had poor sunlight so I have a lot of plants still around 75% 'complete' in terms of delivering fruit. I really enjoyed growing them and I want to try to produce cross-varieties. But, I don't want to contend with the crappy UK weather.

So, I figured I will buy a mylar grow tent (1.2m x 1.2m x 2.0m) and grow in my garage. So, I've been researching for a week and have basically addled my brain. There appears to be a major rift between LED and HPS/MH light 'people' and I've simply seen too much phoney posting to make me take the plunge on shelling out hundreds of pounds on LEDs which are overpriced or don't work. I've been given conflicting info left, right and centre.

Basically, HPS will cost me £500+ a year to run in electricity alone. I guess people 'selling crops' may be able to make that pay but I simply won't. So, it's LEDs or nothing for me.

Then I came across this thread and thought: why don't I try to build my own LED panel?

What I know (I think) so far is that I should aim for Cree, Osram Golden Dragon or Luxeon Rebels in Blue and Red (Blue for early seedlings and Red thereafter).

I'm obviously going to have to learn soldering etc. I'm not averse to learning plenty of things. But, is there any kind of ready made guide (or tips for a noob) that you could point me in the direction of to get me started?

One thing that's bugging me is why are the LED MCPCBs in a star shape :shrug:

Any help / hints greatfully recieved e.g. how many of each type of LED for a grow tend this size, where to buy from (preferably UK) etc.


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## WeLight (Sep 28, 2011)

Kinnza said:


> Those Ilumitex LEDs have good efficiency and are easy to mount, at decent price. However, is not easy to get a good color distribution. I've been looking at the spectral distribution of modules and in general they are too bluish for horticulture, especially for trees. There is need of mix some red modules for each blue/white one and given they arnt wide angle optical emitters, achieving a good color mixing and a good overall spectrum seems a little difficult.



I am not sure your reading the same information I did when I set my poly tent up with these, they come in 4 spectra, ranging from Bluish to very red and you can supplement with 4 modules of individual colours 450nm, 624nm Red, 660deep red and 730 far red and with regards to distribution I have been selling powerleds for 10 years and have never seen a module with built in optics that compares when it comes to even distribution of light. I have just set up a cherry tomato bed with the new Abeo module and have an Eldoled colour mixing driver so can adjust to early growth colours and as the plants age I will tweak the driver to bring in the deep reds to promote bloom and fruit, will post pictures as I get some growth


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## Inkidu (Sep 29, 2011)

ChocHabanero said:


> What I know (I think) so far is that I should aim for Cree, Osram Golden Dragon or Luxeon Rebels in Blue and Red (Blue for early seedlings and Red thereafter).
> 
> One thing that's bugging me is why are the LED MCPCBs in a star shape :shrug:



They come in all kind of sizes
_Dealer links removed_

I also like the drivers from Mean Well. This one would work well with those led. 
The HLG models come with a 5 year warranty but would need these for most led. 
That setup would be very efficient. Still a little confused on exactly how that setup would be configured. Knowing that your driver is in constant voltage mode. Still learning myself. Anyone have an answer? A single 95% constant voltage AC/DC power supply (HLG) connect with many 97% led drivers would seem ideal. 

Hope this helps.


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## Kinnza (Sep 29, 2011)

WeLight said:


> I am not sure your reading the same information I did when I set my poly tent up with these, they come in 4 spectra, ranging from Bluish to very red and you can supplement with 4 modules of individual colours 450nm, 624nm Red, 660deep red and 730 far red and with regards to distribution I have been selling powerleds for 10 years and have never seen a module with built in optics that compares when it comes to even distribution of light. I have just set up a cherry tomato bed with the new Abeo module and have an Eldoled colour mixing driver so can adjust to early growth colours and as the plants age I will tweak the driver to bring in the deep reds to promote bloom and fruit, will post pictures as I get some growth



Except for the F1 tone, all spectra are really bluish for horticulture. And the F1 only has red and blue. Red and blue spectrum combinations has proven to work fine in vegetative growth, or for leafy vegetables (lettuce), but for most plant's species, the lack of essential wavebands hurts the final performance at fruiting stage. You can overcome such problem by adding white, especially white rich on green-yellow emission. But due the narrow beam angle of the Abeo and surexi modules, 50º for half intensity, about 40º for 90% total emission (gross estimation from polar curve), it makes difficult to achieve spectral mixing using separated modules. That is the problem I see with those modules.

It would be perfect if each module emits a good spectrum alone. The relatively square pattern of distribution would make very easy to configure your setup, I agree with that. The problem is I dont see any module accomplishing it. The F3 is the closest to a good alone spectrum, but only when using low to medium irradiances. For high average intensities as used for most plants during flowering and fruiting, more green-yellow would be required.

The FX44 modules tries that, but they are intended for long day flowering plants, as all tones includes a series of far red (730nm). Being a band with negligible photosynthesis effect, it is used for morphogenesis or photoperiodic control. Useful for some growers, but not for many others. It is good to have the option of tones F4, F5 and F8 controlling each channel of color separately, but it is necessary to have a wider selection of spectrums to choose. For example, a module with 2 series of white (preferably a little warmer that the 5700K used) and 2 series of reds, either both 660nm or one 660nm and other 640nm. And more variety too on the beam angles available, for the case you need to mix the color of different modules.

While that narrow angle emission is really great for installing on the egdes of the lamp, IMHO wider bean angles would work better in the center of the array of modules. 80º half intensity beam angles would be a good alternative together with the current 50º. For intracanopy lighting, where modules are placed close to plants, still wider angles would be desiderable, but probably standard emitters fit this application better (mostly, cheaper)


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## bradmc (Sep 29, 2011)

HighlanderNorth said:


> The LED grow lights have LOTS of LEDs, and I understand that they need a mix of red and blue light for vegetative growth, and red for flowering. Well, I only need the type for vegetative growth. But even though they might need a mix of different color lights, they still dont need so many bulbs........



These lights have a lot of LEDs simply because it is cheaper to make units that use 1watt OEM Leds, rather than branded high powered "3watt" emitters used in aquaria lighting.



> Many have over 225 LEDs built in. So why dont they use higher wattage LEDs so they can use less total LEDs and make the fixture smaller? I'm wondering if the quality and power of the LEDs in these grow lights is low and weak?


 
2 reasons. Again, cost effectiveness. You can easily use 200 1watt lLEDs, for cheaper than 20 3watt LEDs from Cree.

2nd reason is because of marketing. A lot of people do not understand LED technology and most people will use power output (wattage) as the cornerstone for basing the effectiveness of the lights. People don't seem to understand that MH and LED are significantly different. So, when people are looking to upgrade to LEDs, they are more likely to buy that 200 watt (200x1watt) LED fixture over that 60watt (20x3watt) fixture simply because of their conditioning on how MH works.


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## Hamburger (Sep 29, 2011)

That XT-E is the sweetest LED I've seen in quite a while.
I'm looking forward to see some new efficient LEDs in other colors in the XT-E package. And the price is super awesome!! I would use them if I had a project like this going on.


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## ChocHabanero (Sep 29, 2011)

I was thinking of ordering 2 x Kit 4 of these: _ Sales link removed_

Would these be good for all-round flowering of chilli plants do you think? Or am I missing something. The kits seem to give me less to mess up through my dubious DIY skills.


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## bradmc (Sep 29, 2011)

ChocHabanero said:


> I was thinking of ordering 2 x Kit 4 of these: _Sales link removed
> _
> Would these be good for all-round flowering of chilli plants do you think? Or am I missing something. The kits seem to give me less to mess up through my dubious DIY skills.


 

They should be fine. I'd lean closer to 650nm on average (Red and Orange) with a ratio of 12:6:2 (12 red - 6 orange - 2 blue)

Blue is really for vegatative growth, which is still important. the redish spectrum is for the flowering (and fruit) of the plant. A high concentrate of red LED's (640-660nm) will sustain a flowering plant perfectly.


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## x101xtreme (Oct 5, 2011)

chainrash said:


> Hey, Great post, thanks for the pics. I'm just starting to dabble with LEDs, so I have a few "newbie" questions.
> 
> 1. Can you explain the wiring a little more? What do yo mean by 3S/2P? Is this how you drive the LEDs at 700mA from the 1400 and 2100 mA drivers?
> 
> ...



I got the heatsinks, LEDs, drivers, and power supply from ledsupply. You can also buy the LEDs and drivers from Cutter Electronics Au for a little cheaper. 3S/2P refers to the fact that I wired the LEDs with 2 parallel strings with 3 PCBs per string. Note that each PCB has 3 XPE LEDs. You're probably going to need a fan of some sort to blow air over the heatsinks to keep the setup cool. I'm using an axternal fan, but you could also wire up a small DC fan in parallel to the power supply with the led drivers. I used a 150W 24V DC powersupply and connected it in parallel to both LED drivers in this setup. Hope this helps.


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## WeLight (Oct 8, 2011)

Kinnza said:


> Except for the F1 tone, all spectra are really bluish for horticulture. And the F1 only has red and blue. Red and blue spectrum combinations has proven to work fine in vegetative growth, or for leafy vegetables (lettuce), but for most plant's species, the lack of essential wavebands hurts the final performance at fruiting stage. You can overcome such problem by adding white, especially white rich on green-yellow emission. But due the narrow beam angle of the Abeo and surexi modules, 50º for half intensity, about 40º for 90% total emission (gross estimation from polar curve), it makes difficult to achieve spectral mixing using separated modules. That is the problem I see with those modules.
> 
> It would be perfect if each module emits a good spectrum alone. The relatively square pattern of distribution would make very easy to configure your setup, I agree with that. The problem is I dont see any module accomplishing it. The F3 is the closest to a good alone spectrum, but only when using low to medium irradiances. For high average intensities as used for most plants during flowering and fruiting, more green-yellow would be required.
> 
> ...



I have compared with Cree leds and at 1-12 ratio of Surexi to Cree stars, cant work out how you find stars (mostly, cheaper) especially as FWHM angles of 120 Degree need collimating, and them your have optic losses on top, I assume you must be talking about other leds. I have found the real benefit at 50 Deg is the PPF is very even across plants, which is difficult to achieve with led and optics not always well matched for the job, also as you move towards peripheral visual spectrum most optics become even more inefficient, UV for example can lose 90% of output with wrong optics material choice


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## Kinnza (Oct 10, 2011)

WeLight said:


> I have compared with Cree leds and at 1-12 ratio of Surexi to Cree stars, cant work out how you find stars (mostly, cheaper) especially as FWHM angles of 120 Degree need collimating, and them your have optic losses on top, I assume you must be talking about other leds. I have found the real benefit at 50 Deg is the PPF is very even across plants, which is difficult to achieve with led and optics not always well matched for the job, also as you move towards peripheral visual spectrum most optics become even more inefficient, UV for example can lose 90% of output with wrong optics material choice



I believe too that Surexi optic would be ideal. I don't see the light distribution itself wrong or inadequate, but spectra of the modules being somewhat inadequate thus requiring some supplementary lighting. And there is when arises the problem, as you need to use wider angle LEDs or add optics to them.

The spectra offered sure will perform well when light densities required are medium-low (shade adapted plants, young plants), but for hight light densities (often required for flowering and fruiting) my experience on this says more balanced spectra are required. As the manufacturer offer customizable modules, I think it could be easily fixed in the future. Modules using too deep red (660nm peak), using more white in the mix, etc.

Anyway, beam angle must be considered together with the distance you use the lamp. For a lamp working closer to plants, it is possible to use wider beam angles. Bare emitters with different beam angles are available in the market way cheaper (for example, Osram Oslon emitters). But mounting them requires some skills that not everybody has, so Surexi modules would be a very good alternative for those who don't want or know to solder. But emitters of similar efficiency with a wider range of colors cost half (or less) of that Surexi modules of similar light emission.

I'm not sure what you refer by ratio 1-12 Crees to Surexi. Do you mean 1 Surexi module performs as 12 Crees?


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## blasterman (Oct 10, 2011)

Being involved with building my own fixtures (terrestrial plant and reef) and helping countless other people build high powered LED fixtures for a couple years there are a few things I've learned from various forums and lots of success stories.

(1) There is nothing produced commercially that you can't build for much cheaper and typically with greater efficiency, thermal management, etc. If you can't solder a series of LED's and use basic addition / subtraction, don't assume others can't. Thermal is really the only complicated aspect. The top bin/flux LED on the market almost always make it into the hands of the DIY crowd well before fixture makers. I'm currently building a light based on XTE's and triple Rebels, and per given wattage there's nothing commercial that can be built for nearly the same price. 

(2) This forces fixture makers to make up all kinds of psuedo science claims to push their products or making the process more complicated than it is. If there's a specific wavelength a plant needs I will listen to other objective growers of that plant having success or visit unbiased white papers. I will not listen to somebody selling a fixture or associated with selling fixtures.

(3) Optics are cheap, not proprietary (see rule 2), and the law of squares isn't restricted to a specific, highly touted brand. Either lower your light, or use optics. The light loss caused from cheap optics is more than made up for given the smaller illumination circle. If you don't want to use optics then the fixture needs to be really low. Not sure why this is made more complicated than it is.


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## Garibaldi (Oct 10, 2011)

blasterman, would you mind if we all just copy and paste your post as a response every time a vendor shill posts something?


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## Kinnza (Oct 10, 2011)

I could not agree more with that post, Blasterman.

I have been involved too on building my own lamps and helping many others to do so for horticultural applications. 

As for (2) actually there is good scientific literature, but it is not linked or used by plant's grow LED sellers because it don't support claims of red/blue mixes having superior quantum efficacy except for very especial conditions. And in most cases, red/blue mixes shows inferior productivity (yield per amount of photons delivered).

Botanists consider photosynthesis as directly proportional to amount of incident photons. And without proof of the opposite, the main thing to consider for a horticultural lamp is how many micromols of photons per second it delivers to the grow area. Standard horticultural lamps state that info in their specs, which is the most relevant.

I have checked that an spectrum well tuned for a given plant and stage of development can have up to double productivity than a generic one. But you need to consider the specie individually, and it is not easy to achieve. In general, plant grow is tightly related to the gross amount of photons received. Typical spectra varies very little in effect when normalized for the amount of photons. Check http://www.controlledenvironments.org/Light1994Conf/1_4_Prikupets/Prikupets%20text.htm and http://www.controlledenvironments.org/Light1994Conf/1_3_Tikhomirov/Tikhomirov text.htm ("3) Maximum photosynthesis of canopies is possible only under combinations of blue, green and red radiation. Any kind of combinations of two of these wavebands or with only one spectral region, always reduces productivity.")


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## IMSabbel (Oct 11, 2011)

blasterman said:


> (1) There is nothing produced commercially that you can't build for much cheaper and typically with greater efficiency, thermal management, etc. If you can't solder a series of LED's and use basic addition / subtraction, don't assume others can't. Thermal is really the only complicated aspect. The top bin/flux LED on the market almost always make it into the hands of the DIY crowd well before fixture makers. I'm currently building a light based on XTE's and triple Rebels, and per given wattage there's nothing commercial that can be built for nearly the same price.



Red herring. This is only true if:

a) your time is infinite any worthless

and 

b) you already have a full workshop for all that needs to be done.

In reality, mass production will kill any DIY approach in terms of cost efficiency.

That does not mean that cheap manufacturers will not try to cheat people by selling crap for 5 times the worth, but your statement is ultimately and generally untrue.


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## evilc66 (Oct 11, 2011)

I wouldn't count on that. Reason being is that the retail price of these fixtures is usually quite high relative to the material costs involved. With the exception of the cheap Chinese fixtures that got this discussion started, most manufacturers are not buying LEDs in volumes high enough to get prices per LED much lower than the average DIYer can get them for. The remainder of the materials required (drivers, heatsinks, fans, hardware, etc...) are still not that much more expensive to the DIYer than the manufacturer.

The only way you can buy a fixture cheaper than you can build is to go with the Chinese fixtures. At that point, you are buying something with lower overall efficiency, and lower life expectancy than something you could build yourself with top end components at the same system wattage. Sure, in the manufacturing world, time is money. To the hobbyist, time is free. And I don't know where you think you need a full workshop to build something like this. All you need is some basic hand tools, a soldering iron, a multimeter, and a handful of common sense. I've helped teenage kids build them on their kitchen table before. It's not hard.

How do I know this? I am one of the people that has built up the reef LED DIY community to the point it is today. I'm also an employee of a reef LED lighting manufacturer, so I know first hand what these components really cost, and the time involved.

Now, I'm not saying "everyone should build, because all LED fixture manufacturers are evil and trying to rip people off". The biggest issue is that the relative cost of the materials, mainly the LEDs, doesn't get much better until you start buying in the tens of thousands.


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## Kinnza (Oct 11, 2011)

I think you both IMSabbel ans evilc66 are right, but just partially. It is true that absolute statements tends to be false. But I agree blasterman statement as far as considering the current stage of the market. Until now, very little good fixtures for plant growing has been available, and there is nothing on them you can't do yourself better and cheaper, at least if you are a LED hobbyist. When true mass production starts, sure DIY won't be as profitable. But way more competition in the market is required to reach that point. Likely, we won't reach it before a pair of years, probably 3-4 yet.

It is true that things are changing. I expect good fixtures comes to the market between this year and the next at decent prices for their performance. But until now, DIY way has been by far the best choice.

I disagree with evilc on the prices at high volumes. Actually, when buying from 800 to 1600pcs of high power LEDs (depending of the distributor), you get access to very competitive prices. For sure you get better prices as larger your yearly buys, but compared with the huge difference with retail prices you got with medium volumes, further savings are relatively marginal, and not a problem at all for an small manufacturer. 5-10$ more a 100W fixture is not anything that does you not competitive currently.


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## slebans (Oct 11, 2011)

Kinnza said:


> When true mass production starts, sure DIY won't be as profitable. But way more competition in the market is required to reach that point. Likely, we won't reach it before a pair of years, probably 3-4 yet.



Hi Kinnza.
I would add another -easier- DIY option to your argument. We have built simple fixtures out of multiple junction boxes/bulb sockets mounted on wood. Currently, most LED bulbs are 17% - 20% efficient. By late fall new bulbs will hit 25% and hopefully we will see 30% efficiencies by the end of next year. We are using LED DMX compatible Dimmer Packs(Chauvet) to control fixtures comprising warm or cool bulbs. You could also mix bulbs of different color temps on a single fixtures and wire them as separate circuits for control. 

LED Bulb prices are on a continual downward pricing trend. Couple this pricing with a 5 year manufacturer's bulb warranty and you have a dependable, easy to fix/modify/update fixture, that will be cost effective when compared to current DIY or mass produced LED "grow light" solutions. 

Finally, I have purchased LED Grow Lights direct from Chinese maufacturers. Unfortuntately, what you order is not always what is delivered. Service issues are even worse.

Stephen Lebans


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## Anders Hoveland (Nov 22, 2014)

For the most part, plants just need 660-670nm deep red wavelength light to grow. They also need a little blue light to tell the plant where to grow _towards_.
There are a very small number of plants that benefit from other wavelengths also. For example, red lettuce requires some UVB wavelengths to blush with that appetizing red color.

I am fascinated by all the specialized technology used in the attempt to make "full spectrum" grow lamps, and these technologies have much potential carry-over for use in ideal lighting for humans. However, the plain reality is that plants do not need full spectrum light for ideal growth.

Regular phosphor-converted white LEDs are not efficient for growing plants, their spectrum typically lacks deep red wavelengths.


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## SemiMan (Nov 23, 2014)

Stick to what you know Anders .... This topic certainly is not it.


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## SemiMan (Nov 23, 2014)

Oh and its 3 years old


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## snijok (Jan 4, 2015)

I made a grow light with 60cm MakersLED heatsink and 143 LEDs. I run most them at 1A current, mostly due to driver choice. Drivers are handmade, based on al8805. LEDs are: 56pcs CREE XB-D 4000K, 45pcs Led Engine LZ1R200 660nm, 30pcs XB-D blue (25 of which are 450nm and 5 are 470nm), 5pcs Led Engine 623nm and 3pcs 740nm, 4pcs UV Led Engine (2x 365nm and 2x 405nm). Drivers are combined in a way that I can adjust (no PWM) the intensity of each wavelength. PSU is Meanwell 24V 600W, even though the lamp takes only about 410W.


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## degarb (Jan 10, 2015)

Just a quick thought, but I wonder what the effect of reflective mulch would have on the efficiency of such a set up.


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## Shawnro (Jan 13, 2015)

That looks impressive. But why not just get three or four 100watt led chips and mount them to the heatsink you will need a small 12 volt fan to help cool but you would have more light and a lot simpler set up to work with.


Sent from my iPhone using Candlepowerforums


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## evilc66 (Jan 13, 2015)

Because those awful 100W Chinese LEDs won't have the efficiency, controllability, or the spectral spread that the above setup will have.


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## Shawnro (Jan 14, 2015)

I don't think they would be too far behind what you have. But different strokes for different folks. 


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## htsystems (Mar 10, 2015)

New here. I tried some of the 100w led full spectrum LEDs. They worked good but the test was with some hps lights too.
Now they make 50w full spectrum chips that have some white that should do better. 380nm-840nm full spectrum.
That is my next test. Also you need to use a lens on the cob LEDs, I found a 60deg lens worked best.
LEDs will do better and I have seen they do work.
The 50 or 100w LEDs need a good heat sink and fan on them.
I see working temps of 160F, I'm sure they can work there fine but it has to kill the life.
In my setup the LED base never got above 110F. And to run at 50 to 75% power will make them last longer and put out 
more lm/w.


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## WeLight (Mar 11, 2015)

I sell leds, I love leds, but having spent a lot of time on Grow light development. the conclusion is that led grow lights lack punch, color control is a wonderful thing with different wavelength leds. When I compare the performance of HPS and its orangy/greeny spectrum, it does not seem to match the science on what plants need. The reality is plants do want spectrum, but more than that they just want radiant energy/intensity in spades. I believe the approach you need to take is lots of highpower white COB style, some 15000 white lumen COBs as your base platform, then look to add 450,630,660, 730nm, around it for bursts or time periods relative to your plant cycles. The problem is the directional nature of leds means you may have plenty of PPFD directly under the led light, but move off axis?? then when you do a PPFD anaylsis of HPS, the PPFD numbers are consistent all over the plant, my two cents worth


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## SemiMan (Mar 12, 2015)

WeLight said:


> I sell leds, I love leds, but having spent a lot of time on Grow light development. the conclusion is that led grow lights lack punch, color control is a wonderful thing with different wavelength leds. When I compare the performance of HPS and its orangy/greeny spectrum, it does not seem to match the science on what plants need. The reality is plants do want spectrum, but more than that they just want radiant energy/intensity in spades. I believe the approach you need to take is lots of highpower white COB style, some 15000 white lumen COBs as your base platform, then look to add 450,630,660, 730nm, around it for bursts or time periods relative to your plant cycles. The problem is the directional nature of leds means you may have plenty of PPFD directly under the led light, but move off axis?? then when you do a PPFD anaylsis of HPS, the PPFD numbers are consistent all over the plant, my two cents worth



- I am not sure I would draw the same conclusions:

- 630nm is of questionable benefit when you have 660nm. I have not seen any proof of a different action spectrum in plant growth with 630nm over 660nm. On the other hand, 660nm is closer to the chlorophyll peak and 660nm LEDs tend to be almost 2x the wall plug efficiency of 630nm if not 3x when they are warm.

- 450nm is of course good

- 730nm has been shown to activate certain photochemical reactions in plants so all good

- There may be benefit in near UV for some plant species

- Some recent findings on green light may dispel the benefit of broadband white light or at least suggest the greatest benefit is from the green in that light. Red/Blue do not penetrate very deep in the leaf and may saturate the chlorophyll near the surface. The green penetrates much deeper and is hence able to activate a greater volume of chlorophyll even if not as efficiently as red/blue. Currently white LEDs are the most efficient at a broadband green so it may be mute point, but that may point to using cool white for the green portion and 660/450 for the rest. It would be interesting to try the lime green Luxeon.

- To your point, getting light into all the canopy is important. To that end, lots of smaller emitters focussed may be the best for coverage, and if you can do it, illuminating from the sides as well.


Semiman


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## snijok (Mar 13, 2015)

I believe that grow lights should mimic a distributed source. 
COBs are ok when one has e.g. huge greenhouse where there are many tens of light sources near ceiling. Then it does not really matter how bright is each source (I mean flux density at the source). 
For smaller applications, where the total power of the light is in range 100-500w it's better to avoid single powerful chip placed in reflector. It may burn the plant.


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