LED Light DIY

As many of the DIY guys, I used GODs instructions (and I mean KNNAs for the LEDs and VerdantGreen for the MJ Gardening).

but as KNNA was busy and couldnt be reached this winter I had to source my LEDs from other sources. I mainly used DealExtreme for 5Watt Whites running at 700mA (no brand though, and right now you could find better deals elsewhere), and Cree for Red and Royal Blue (both running at 550mA sourced from cutter ).

for vegetative I used 3W, 3B, and 6R all running at 630mA mounted on 3 PC heatsinks, totaling 28W at the plug
To be accurate it stabilises to 28 after 20minutes, as the noname dealextrem driver start from 31W -starting voltage at around 42V dropping to 38V after 20-30minutes, I dont know why, the meanwells dont have that kind of behaviour ).

Passive cooling, temperatures reaching 48C for REDs (they are a little bit overdriven at 630 as max is 700mA), 42C for the blues (as they have max 1000mA) and 58C for whites (they are infirior quality to CREE and have a nominal current at 700mA, so I thought running at 630mA is not overdriving, so the temperatures are ok. No fans apart from exhaust fan (12cm PC fan, regulated at 7V), just passive cooling for the heatsink (well maybe a small fan would be good in vegetative but I dont like the added noise)





as for the construction, as you can see, I used 2 pieces of aluminum profile with thermal glue in order to connect the 3 Heatsinks together, but Im not very satisfied with the temperatures achieved. The 2 profiles connecting the 3 heatsinks also warm up, but that doesnt mean much. If I had to go over again, I would use aluminum profiles and spread the LEDs over a bigger area. That way I would certainly have lower temperatures, as PC heatsinks are not very good for passive cooling.
The 2 big ones were rated for around 65W but without a fan this capacity is greatly reduced.




in the flowering compartment. I used 28R 4B and 5W . The whites were running at 700mA, and the blue/red on two parallel strings under a meanwell at 1100mA (so 550mA each string).


How to calculate your Constant current supply
first you have to choose your LEDs. Example. I used 28R 4B 5W . 28R Cree XPE, 4B Cree XPE, and 5White chinese 5w each.
Reds are working at around 550-600mA (max700) and 2,1Volts.
Blue are working around 700mA (max1000mA) at 3,3V.
Whites are working at 700mA at 6,5V

so all in all I need 28*2,1V+4*3,3V+5*6,5V=104,5V to give some head room make it 107-108.
I also need 700mA for White/Blue and 550-600mA for Reds which makes life a little bit complicated.
Now we have to choose the drivers. I went for meanwells which are stable. We are trying to get as little as possible parallel strings and if we make 2 parallel strings we use exactly the same leds on each string in order not to have any unbalanced effects.

So I chose to use 1 700ma,20W driver for the White ones and then I chose an ELN60 (60w) running at 1,2A with 2 strings of 14Reds and 2Blues each. So each string would get 550mA which is underdriving the blues, but for 4 blues I didnt want to spare an extra driver. I put a correct fuse (630mA) before each string and everything was set.



Heatsink Construction

I have some time so I'll give some more instructions on construction. I used aluminum profiles as heatsink. I used Π profiles measuring 2x3,5x2. That gives me (3,5x2+2x2+2x2)=15cm2 of surface area per cm of length used. I went for around 100cm2 per Watt as I wanted to mount a mostly passive system. I cut the profiles to 50cm each (my cabinet has 60cm of width), so 50*15=750cm2 of total area per cutted profile = around 7watt per profile.

Then I made 2 10mm holes on each side and put a 8mm threaded rod secured with nuts. On 4 profiles that I had to put more Watts, I glued with thermal glue in the center a smaller Π profile (1,5x1x1,5cm).






and led temperature never goes over 42C for Blue, 43C for Red and 46C for Whites which is fine. Just passive cooling and one 12cm PC exhaust fan on a DIY carbon scrubber (but it needs replacing)

Ιn this run I m driving the flowering compartment at 59W total at the plug and we will see the results (hopefully they will be the same).

the flowering took nearly 65days.

each string is protected with a fuse and a zener, but in my experience meanwell drivers are as stable as Pyramids. I wouldnt say the same for the deal extreme piece, but it was cheap and quite suitable to my needs (the meanwell running at 700mA would be too much for the Reds)

im not very proud of my construction skills but it works.

(this was the plant 10days before harvest)

For the future Im thinking of putting a low RPM fan circulating air in each cabinet. That is more in order to heat a little bit more the sativa dominant plants, than to cool the heatsinks. Temperatures in the cabinet are around 20-22 in flowering and 22-25 in vegetative, which I think are on the down side of the Cannabis spectrum

If you have any questions please fire away. and if anyone needs help building such a thing, dont hesitate to ask.

as for the sources
Cutter in Australia is very helpfull and the prices are right.Cutter.com.au
Led Teille in ebay has quite cheap chinese White and Blue LED. Less than 1eur per 3watt led which of course are not as good as the Cree and Osrams , but on the other hand they are dirty cheap.

and for the meanwells constant current regulators the cheapest source I found in Europe was Proconnect

Did another tutorial for pretty much the same stuff.

https://www.icmag.com/ic/showpost.php?p=4441582&postcount=7

I, however, use 12V PC Fans to cool the panels, I like them arround 30°C. I love your design!

alkalien said:

Did another tutorial for pretty much the same stuff.

https://www.icmag.com/ic/showpost.php?p=4441582&postcount=7

I, however, use 12V PC Fans to cool the panels, I like them arround 30°C. I love your design!

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Yep Thats what I mean I m not proud of my construction skills. Both your work and your tutorial are exceptional

I loved the XM-L and nowdays they are dirty cheap for what they emit, but I had hard time to find a proper driver for them. 2500mA is too high a current and 3,4V each is too low voltage.

KNNA and others that used only a W/R mixture had some complains, and added blue back to the spectrum. What are your results?

And we also have to say, with the new lower led prices, building your own is at LEAST twice as cheap (most times is 3times cheaper) than a commercial unit (and Im not going to argue about the quality of the LEDs). So even guys if you screw up and burn all your LEDs, you could buy a second run and still be cheaper

Great work!

fyi: I've been running the Cree XP-E reds at 700mA for two months without any issue. As it is now, you're not even at half their max junction temperature.

bonsai said:

Great work!

fyi: I've been running the Cree XP-E reds at 700mA for two months without any issue. As it is now, you're not even at half their max junction temperature.

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Well I wouldnt want to wear them out prematurely, at least not until a new generation of REDs come out and be cheaper than the ones I have


Spec says Imax=700mA and maybe MAX junction Temperature is 150C but at that temperature, relative luminus flux drops to 50%
Even at 60C you have a 80% Relative luminus Flux. So in reality you just waste energy for no additional light . Red LEDs are a little bit touchy

So maybe having a fan circulating air around the cabinet is not such a bad idea


Oh and as I said, Im not pretty sure about my calculations concerning Tj . For example I calculated Thermal resistance to 10+1+4=15C/W
Tomorrow I will tell you the temperature of the heatsink just over the leds

very nice

so along with this post

blimblom said:

my first LED run had seeds on, so I dont count it really. I growed nearly 200 healthy seeds, so I wont need to pay any of the premium seeds anymore.

my second LED run yielded 34+29grams (two plants) = 63gram of dried matter

My system is a 67watt total consumption DIY LED system, so we have a GpW of nearly 1 (or 0.94 to be precise) which is exceptionally good for my standards. Im not an exceptional gardener and Im sure there is some room for improvement . Maybe I have to run the LEDs a little bit softer or harder Im not sure yet. But on this run the consumption was 67Watt total at the plug

the plants were Martian Mean Green grown from seed in SCROG (the best method of growing with LEDs IMO)

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you've been tagged !!!


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I use a 2A driver, running three strings at a little less than 700mA each with the reds and blue. I then solder them together for three or more XM-L for them to be inline with. I can now run the Osram Golden Dragon at those 700mA and the XM-L at 2A. That's the best I could do supplying them the best possible current.

I use different Meanwell drivers, for this setup I like the CEN-100-48 100W 48V.

Thanks GP73LPC , really glad I can share back to the community all the things I learned here.

Did some more calculations for Tjuncture. The Temperature I measure is certainly the temperature of the LED and some part of the starboard. So in reality my R(th-j-b) for RED is (10+1)=11C/W which gives a Tj of 54C when the Tb (the temperature I measure) is 41C. (Total Power is nearly 1,2W)

So lets calculate again Tj for REDs (which are the most touchy).
In the Flowering cabinet I have Tb=41-42C which translates to Tj=54C which gives me nearly 90% of relative luminus flux (not bad)
In the Vegetative Cabinet I have Tb=48C which translates to Tj=63,5C which gives me nearly 80% relative Luminus Flux (worse but still).

So all in all if I pull my shit together and add 1 small 8cm fan in the vegetative cabine to circulate the air around, I would maybe get a Tb=42C for my Reds and 10% more lm out of them .

For those interested in that kind of nerdy stuff, read this,
And if anyone thinks my calculations are screwed, please dont hesitate

deleted posthttp://tapegysegaruhaz.hu/en/shop_search.php?search=lpc

Seriously if you guys could break everything down into a how to guide that would be awesome. I just don't understand the I'm running this "string" this way and the rest of the jargon is also confusing. Then a little section on drivers, soldering, do's, don't's, all that I reckon we'll see a fair few people going DIY and with help from you guys we'd be able to build some wicked lighting. I can honestly say I'd rather buy the materials and build it myself even if it costs more just to know that if things fuck up I can fix it and not have to wait on some shifty co. to respond to emails asking for help. Man... I really envy my little brother sometimes, prick could build one of these easily and he doesn't even know what they are. Electrical skills for growing marijuana... there's a book!

Mountain Monkey(and others) - I've been debating about asking the mod's to set up a separate section for the DIY LED stuff. I'm partway through the assembly of mine, and have found a lot of great information on here, but it is so scattered around that it is difficult to compile. People like KNNA and Shafto have been a tremendous help, and I keep seeing good information dropped into the middle of other threads by Freedom Grower, SupraSPL and many others - I think that one centralized spot would be very beneficial. Any thoughts?

Mountain_Monkey said:

Seriously if you guys could break everything down into a how to guide that would be awesome. I just don't understand the I'm running this "string" this way and the rest of the jargon is also confusing. Then a little section on drivers, soldering, do's, don't's, all that I reckon we'll see a fair few people going DIY and with help from you guys we'd be able to build some wicked lighting. I can honestly say I'd rather buy the materials and build it myself even if it costs more just to know that if things fuck up I can fix it and not have to wait on some shifty co. to respond to emails asking for help. Man... I really envy my little brother sometimes, prick could build one of these easily and he doesn't even know what they are. Electrical skills for growing marijuana... there's a book!

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The problem with DIY is that people have a varied degree of knowledge about all the stuff and sorry for the jargon, I ll try to explain a little bit (and yes a sub-forum would be good)

First you have to remember that
Voltage x Ampere = Watts
and that LEDs are devices that feel very well with constant current (ie Amperes) than constant Voltage. Thats why we buy specialized drivers (transformers) to drive (to give power) to the LEDs. Most other devices (like your laptop) prefer to have constant voltage and variable current (amperage). With LEDs is the other way around

For example a RED led works from 100mA to 700mA but at the same time can only work from 2.1V to 2.4V , As you see you see the LEDs are extra sensitive to those small variations in Voltage while they can accept a big range of current.

Also the RED led in our example has a typical Amperage of 350mA which is the power they tested it. At that current (350mA) this LED produces 64Lumens. But if I double the current at 700mA, the same led will produce more Lumen but not double the lumen (more likely 180% of the rated 64Lumen).

so this RED LED driven at 350mA gives us 350mA *2,1V=,073W and 64lumen
and driven at 700mA gives us 700mA*2,3V= 1,6W and 115Lumen.

The problem is that as this LED is driven harder, it produces more heat and heat is something the LEDs dont like, because it decreases their life expectancy AND their output. For example if our LED at 700mA reaches a junction temperature (thats the inside of the LED) of 45C-50C, its output capacity is reduced to 80%, so inreality we will not get 115Lumen but 92Lumen. Thats why we use half our effort to build heatsinks for our LEDs

So we have to decide. Is it worth to spend double the power (and money) driving this RED LED at 700mA, only to get half the gain? Where I live power is very expensive so I dont find it a good solution. On the other hand, driving the LEDs harder (more power) means that you will need less LEDs in your setup to achieve the amount of light you would like to


you can see all these specs here

and of course you can start reading what KNNA has written all over in order to be introduced to the LED lighting

^^^^ good post

blimblom said:

...
you can see all these specs here
...

Click to expand...

i've got another link for you: http://pct.cree.com/

First you have to remember that
Voltage x Ampere = Watts
and that LEDs are devices that feel very well with constant current (ie Amperes) than constant Voltage. Thats why we buy specialized drivers (transformers) to drive (to give power) to the LEDs. Most other devices (like your laptop) prefer to have constant voltage and variable current (amperage). With LEDs is the other way around

Click to expand...

Transformers are voltage controllers, what LED drivers are is currant limiting devices. LED drivers can be efficient to a greater or lesser degree. That is why reading currant draw on a LED luminaire (assembled lamp) can be very deceiving as inefficient drivers make the lamp draw more power in relation to the actual light output, making it appear to be more pwerful to someone glancing at the specs witout knowing what is actually inside. The worst of these don't actually contain a "driver" per se, but a terminating resistor that burns up the lion's share of the currant, leaving very little currant left for light production.

@hempguy you mean there are really ready made lamps that dont use a driver and only use a resistor? thats perverse. A driver is not that expensive specially when you charge so much for the whole setup. And sorry for the terminology mix up. Most of my electronic knowledge comes from my father who was an electronics man and the terminology wasnt in english, so I mix up. Thanks for the clarification.

@asde nice calculator.

Hempyguy said:

Transformers are voltage controllers

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There are many types of transformers, but perhaps the most commonly used are voltage converters, not voltage controllers. There is no active "control" of the output voltage - it is simply converted at the ratio of the primary to the secondary windings. If there is a voltage fluctuation on the primary (inbound) side, it will be reflected on the secondary (output) side at the same ratio that the transformer is wound. For instance, if you have a transformer that converts 120 vac to 12 vac, a surge on the power line to 140 volts will make the output go to 14 vac.

Incidentally, transformers only work on alternating current (ac), not on direct current (dc). They can be used to convert the secondary voltage to either a lower or higher voltage than the primary, or maintain the same voltage and provide isolation. Also, the wattage remains constant - only the voltage and amperage change.

@hempguy you mean there are really ready made lamps that dont use a driver and only use a resistor? thats perverse. A driver is not that expensive specially when you charge so much for the whole setup. And sorry for the terminology mix up. Most of my electronic knowledge comes from my father who was an electronics man and the terminology wasnt in english, so I mix up. Thanks for the clarification.

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You better believe there are lamps made just that way.

And there are others that use cheap inefficient drivers that allow them to use lower cheaper LEDs and still have "higher wattage" specs.

There are many types of transformers, but perhaps the most commonly used are voltage converters, not voltage controllers. There is no active "control" of the output voltage - it is simply converted at the ratio of the primary to the secondary windings. If there is a voltage fluctuation on the primary (inbound) side, it will be reflected on the secondary (output) side at the same ratio that the transformer is wound. For instance, if you have a transformer that converts 120 vac to 12 vac, a surge on the power line to 140 volts will make the output go to 14 vac.

Incidentally, transformers only work on alternating current (ac), not on direct current (dc). They can be used to convert the secondary voltage to either a lower or higher voltage than the primary, or maintain the same voltage and provide isolation. Also, the wattage remains constant - only the voltage and amperage change.

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__________________
The point is that a simple dual coil transformer is not up to the job of protecting the LED whilst making sure that it is not starved for current thus reducing light output. An unprotected LED will quickly "run away" in terms of current and quickly destruct in a burst of light (and heat). Voltage controllers that work on DC are not any kind of transformer by the way, they are DC to DC voltage converters. A LED drivers might be best described as a self contained regulated DC power supply.

Peace and enlightenment, Bro!

BTW the OP used the best "pre-rolled"drivers I am aware of, good onyou, bro!

Hempyguy said:

The point is that a simple dual coil transformer is not up to the job of protecting the LED whilst making sure that it is not starved for current thus reducing light output. An unprotected LED will quickly "run away" in terms of current and quickly destruct in a burst of light (and heat). Voltage controllers that work on DC are not any kind of transformer by the way, they are DC to DC voltage converters. A LED drivers might be best described as a self contained regulated DC power supply.

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Absolutely! I was just trying to add a little clarity for Mountain Monkey and others without a technical background.

Actually there is no alternative to Meanwell drivers. Well, there shouldn't be any...

Today you get electronic transformators which don't reduce voltage by a fixed ratio but will make sure the correct output is supplied, therefore controller is pretty much correct.

Modern power supplies work at something like 100 to 265V and 50 to 60Hz, how they do, please don't ask me