Building a Full-Spectrum LED Light Array for My Grow Station

[kamko15]

I recently began making a cabinet into a grow station. It's almost finished, but I'm having trouble with the lighting system. In the beginning the idea was to make a full-spectrum LED light array of no particular voltage. I wanted to mimic this array I saw on LED Lights and Light Fixtures

http://i.imgur.com/6WOIX.jpg
http://i.imgur.com/1tLt9.jpg

Then after I looked into it more I decided to use different types, and colors of LED That would produce the same full-spectrum light pattern. I chose a http://www.superbrightleds.com/moreinfo/component-leds/5mm-warm-white-led-30-degree-viewing-angle-15000-mcd/263/, http://www.superbrightleds.com/moreinfo/component-leds/5mm-blue-led-30-degree-viewing-angle-4600-mcd/267/, Super Red, and http://www.superbrightleds.com/moreinfo/component-leds/5mm-uv-led-30-degree-viewing-angle-380-nm-20mw/631/. I put links to the specifications of each LED.

I purchased 3 pieces of aluminum sheeting from Ace hardware and made 3 panels to mount the LED in.

http://i.imgur.com/cxf5z.jpg

These two are {18x9} in and have 99 holes {(11x9)} {Length x Width}

They will hopefully end up looking like this.

http://i.imgur.com/JkXPp.jpg

The other panel is { x } with 84 holes {(7x12)}

http://i.imgur.com/361kt.jpg

This is what I'm planning.

http://i.imgur.com/KQDRS.jpg

P.S. Here a link to an http://led.linear1.org/led.wiz

I don't have much knowledge on the subject and need help. Please feel free to give your input.

Moderator note: Replaced oversized images with links to the images and cleaned up the post a bit to make it easier to read.

 

[rhody]

Kamko,

Good idea, if I were you I would draw a grid with a yardstick, then take your aluminum to someone who has a nice drill press, you will get perfect holes at the perfect angle for your leds, please keep us informed of you out of pocket expense for LEDs, wiring, etc... BTW, I am looking for a solution similar to this. I am betting you can make a decent replica of what the add advertises for about $ 150 US dollars. See if I am correct. Then, all is required is time and labor on your part. If you get it done and want some ghost pepper seeds to start as an experiment, PM me and I will send you some.

Rhody...

 

[NascentOxygen]

You seem to be working on the premise that the plants you intend to grow will do best under full-spectrum lighting. This may be correct, I don't know. But if that's not correct, then it might mean you are not maximizing your bang for your buck. Have you done a google search to find the optimal spectrum of light for green plants, or for those that you plan to grow? It may be that one or more of the colours you have used might be better replaced by another, if plants do better with a narrower spectrum.

If you mix LEDS like this, knowing that different LEDs have different voltage/current requirements, how are you going to power them? Obviously you will reach a compromise, but it may be even easier if there were fewer colours, or if you used equal numbers of the different colours.

I suppose you'll be buying high efficiency LEDs so that for a given power usage you maximize the radiation?

Do you have an arrangement that can raise and lower the LED plate so that it can be kept really close to the upper leaves of the plants as they grow? If so, maybe it would be better to group one LED of each colour in a close cluster, and replicate this multiple times, instead of going for a geometrically-pleasing design. As it stands, plants on the perimeter will receive minimal UV, and plants in the centre won't get much RED. LEDs are much more directional than light globes, so each LED will deliver most of its light directly down. This might encourage plants to grow more spindly as the uppermost leaves block the light and the lower ones are shaded and get little.

What design do you have for the power supply?

Good luck with you plans to have home-grown lettuce in mid-Winter!

 

[rhody]

You also will need a heat sink, think, C channel aluminum, stacked side by side and a decent fan to dissipate the heat, have a look here, this may give you some ideas.

Rhody...

 

[Antiphon]

Plants grow best in a mixture of red and blue light. You don't need the full spectrum.

 

[kamko15]

Hey, glad to see people posting on here. thanks rhody that link was pretty interesting,but I

would use this compound as a http://www.platinummicro.com/product.asp?pf_id=TPZ3


I need lessons on wiring LEDs

I have no clue how to power the arrays, or what I would need to power them. (driver,ect)

weather to do them all on a separate power source or all together. (if that's even possible)

I guess the Main question I have and the reason for this post in the first place is to find out

If this is possible and if so how to do it.

 

[jim hardy]

need lessons on wiring LEDs

I have no clue how to power the arrays, or what I would need to power them. (driver,ect)

weather to do them all on a separate power source or all together. (if that's even possible)

I guess the Main question I have and the reason for this post in the first place is to find out

If this is possible and if so how to do it.

Find what is forward voltage drop of LED's at their operating current
not max current, something less so they'll last a long time

Connect enough LED's in series to get near a convenient voltage - maybe 12 volts is convenient ,
so you'd make a string that's nine or ten volts

Now add a resistor to the string that'll eat up the remaining two or three volts.
V = I X R
so resistor needs to be (volts you need to have eaten) / (amps you decided to use)
and watts eaten by resistor will be (Volts Eaten) X Amps, so buy one rated twice that many watts.

Make as many similar strings as required to accommodate all your LED's
and connect them in parallel.

Now add up the amps
and go looking for an inexpensive power supply
of that voltage and current.
Plenty of surplus sites carry them.
example: http://www.mpja.com/12V-17A-Phihong-Power-Supply/productinfo/18091+PS/

A 12 volt 6 amp battery charger is about thirty bucks at Tractor Supply
and will limit current should something short out.
Try it first though , some of them hum a bit.
And it'll actually make around thirteen volts.

 

[kamko15]

Find what is forward voltage drop of LED's at their operating current
not max current, something less so they'll last a long time

Connect enough LED's in series to get near a convenient voltage - maybe 12 volts is convenient ,
so you'd make a string that's nine or ten volts

Now add a resistor to the string that'll eat up the remaining two or three volts.
V = I X R
so resistor needs to be (volts you need to have eaten) / (amps you decided to use)
and watts eaten by resistor will be (Volts Eaten) X Amps, so buy one rated twice that many watts.

Make as many similar strings as required to accommodate all your LED's
and connect them in parallel.

Now add up the amps
and go looking for an inexpensive power supply
of that voltage and current.
Plenty of surplus sites carry them.
example: http://www.mpja.com/12V-17A-Phihong-Power-Supply/productinfo/18091+PS/

A 12 volt 6 amp battery charger is about thirty bucks at Tractor Supply
and will limit current should something short out.
Try it first though , some of them hum a bit.
And it'll actually make around thirteen volts.

The LED specs are linked in the post. I appreciate the advice, but maybe you would have some as pertaining to my specific project?

 

[Evo]

Please make sure that you do not post images larger than 800x600 pixels, please resize your images.

Also, the lights you posted are only 5mm and from everything I've read, they will not be strong enough, you need 10mm - 1watt lights.

If you are thinking of building a diy grow light please take note of this.
Each and every led needs to be atleast 1watt each. Anything below that will be useless so don't use old leds out of toys or old boards, they simply will have too little Total lumens versus lumens per watt. You need atleast 10mm LEDs with 1watt per LED to supply enough light to the plant anything lower will not work. A good combination is a pannel made from 75% 1watt red high brightness leds, 20% 1watt blue high brightness leds and 5% 1watt amber high brightness leds. somewhere in the region of 660nm for red and 460nm for blue
There is also no effective difference in penetrative power for horticultural purposes between a 1W LED and a 3W LED. So anything over 1watt is just wasted. This means brightness has very little to do with the benefit you will get once you use 1wat leds. Don't confuse this with a pannel made from say 20 LEDs rated a 10watt as to one with 10 LEDs rated at 10watt. As the 20 watt pannel will use the useless 0.5watt leds verses the 10watt pannel that uses 10x10watt 1watt LEDs that are ideal. This has been tested and proven that 1watt single LEDs have great benefit to plants and anything less is just a waste of time and has no benefit at all to plants. The same applies with going brighter than 1watt has no benefit either.

http://www.instructables.com/id/high-power-LED-grow-lights-M.k2/

 

[jim hardy]

The LED specs are linked in the post. I appreciate the advice,
but maybe you would have some as pertaining to my specific project?

gosh i thought you'd be using higher power m Luxeons or something.

well. i see forward voltages of 2.2, 3.5 and 3.2 volts at 30 milliamps.



one of each in a series string would add to 8.9 volts

IF you selected 12 volts as convenient,
your resistor would eat the remaining 3.1 volts
R = V / I = 3.1 / 0.03 = 103 ohms, 100 or 110 is nearest standard value
power is only 0.093 watt so a 1/4 watt will do...
To accommodate your 84 (was it?) lights
you'd need 28 such three light strings (each with its own resistor)
and current draw would be 0.03 X 28 = 0.84 amp

which you can get from a thrift store wall-wart supply , aka plug transformer
http://www.mpja.com/12VDC1500mA-Used-Regulated-Plug-Supply/productinfo/18668+PS/
Look for one rated 12 volts, 1000 ma or higher.

that's the method. Have fun!

 

[kamko15]

looked over all of the responses and tweaked the design slightly.

I am completely new to this and all of the feedback really helped.
Now that I looked into it a little more I see 1 Watt LEDs would ultimately produce the best plants, so I ditched the 5mm and went with these. RED 630nm, RED 660nm, Blue 450nm, and Warm White.

This was originally the array with 84 LEDs. It now consists of 70 1 Watt LEDs .

[URL=http://imgur.com/wrmHW][PLAIN]http://i.imgur.com/wrmHW.png[/URL][/PLAIN]

I know that the diagram above is NOT correct.

My question, is this possible or am I just pipe dreaming.
I know that I need some form of current limiter, or driver, but I am not sure what exactly.

is there anyway to use a smaller power source for this project? if so please let me know!

I really appreciate all the input I can get on this project thanks in advance!

 

[NascentOxygen]

well. i see forward voltages of 2.2, 3.5 and 3.2 volts at 30 milliamps.

one of each in a series string would add to 8.9 volts

IF you selected 12 volts as convenient,
your resistor would eat the remaining 3.1 volts
R = V / I = 3.1 / 0.03 = 103 ohms, 100 or 110 is nearest standard value
power is only 0.093 watt so a 1/4 watt will do...

Were I to build this, I would want to tweak the currents under full operating conditions by, e.g., tapping along an 82Ω with a string of small resistors in series. Otherwise, he could end up with currents being double what he'd planned for. A 12v wall wart could be anything from about 10.5v - 13v under full load, and small differences in diode voltages may accumulate.

In practice, the convenience of having a current source feeding each string may well be worth the extra effort of constructing it.

I'd look for a switched mode wall wart, much cooler running than the heavy iron + copper block.

OP needs to calculate the heat dissipated in the lights, too. Plants would probably enjoy a little warmth, but not excessive heat.

Also, OP hasn't addressed some questions I raised.

 

[jim hardy]

Your diagram is a good start...
just needs something to control current in each row.
There's always more than one way. The resistors i suggested are simplest, and cheap.
There are exotic LED drivers you could use
but there's no way to drive it with less power than it puts out.
You can use one supply, or several smaller ones.
How much current do you want through your led's?

Here's a fairly beefy supply. its datasheet says it'll adjust +-10% so it should make 26 volts okay.
http://www.mpja.com/24V-45A-100W-Power-Supply/productinfo/16015+PS/
and another, beefier yet...
http://www.mpja.com/28V-108A-NAO-Power-Supply/productinfo/18927+PS/

both are regulated so should hold constant voltage.
dont use an unregulated one for LED's for reason NascentO2 mentioned,
unless you use constant current drivers instead of resistors to set current.
7805 datasheet shows how to use it for that purpose, but you'll want a 28 volt supply in order to have enough "headroom"

check hobby and surplus sites.

 

[rhody]

This is overkill to the nth degree but will give you something to think about as you put together your light project, who knows, maybe it will inspire you to more lofty goals, http://plantlab.nl/4.0/index.php/products-and-services/plant-production-units/

...the following options are separately controllable: light color, light intensity, light color ratios, day length, infrared, light temperature, root temperature, plant temperature, irrigation, nutrition, air velocity, air composition, humidity and CO2.

Cool technology, heh ? I plan to do more digging later and will report anything I think may be useful to you in your project.

Rhody...

 

[kamko15]

I've finally decided how I'm going to assemble the 70Watt (70x1W) LED array.

That dose not mean that I am ready to build it, not even close. I am posting this method so

that you guy's can let me know if it will work, and it probably isn't the most efficient method

so please, let me know, I am open to suggestions.

However if this is a really good way to wire em up then please let me know what

components I'm going to need, what I might need to know, I mean anything that can help.

All of the information on the LEDs in on this thread.
The image of this array is link to the site hosting it, and on that site you can edit so if you

ever want to use that too respond to this post you can.

 

[jim hardy]

only trouble i see is your white LED's are 750 milliamp

and others are 350 milliamp

so the white ones will be not at full intensity (probably okay)

check LM7805 datasheet for how to use it as constant current driver

and i count up 3.5 amps load


and please go back and either shrink or delete those [too wide wide wide ] pictures so this thread fits on a screen

 

[rhody]

and please go back and either shrink or delete those [too wide wide wide ] pictures so this thread fits on a screen

Jim, kamko,

kamko can't they are locked at this point only a mentor can re-size them.
I sent a report to them, hopefully one of the mentors will be so kind as to re-size them.

Rhody...

 

[kamko15]

I couldn't Edit the previous post so here's the diagram again this time the wiring may look a

little more correct.

 

[Greg-ulate]

Very cool project! I hope you are learning a lot about electronics along the way.

The array calculator in the original post is very cool as well. my suggestion is that you don't necessarily need to connect adjacent LEDs to each other electrically, you could group them by color and then use the LED array calculator to determine how many rows you should have and what resistance to add in each row for current limiting.

only trouble i see is your white LED's are 750 milliamp

and others are 350 milliamp

so the white ones will be not at full intensity (probably okay)

to make these currents more similar you could wire 2 of each 350mA LED in parallel, so that 700mA total would flow through the combination, providing more current to the 750mA LED, boosting its intensity.

If I were going to design something like this I would probably use something like an old PC power supply to get 12V, wire as many LEDs in series as I could such that the combined forward bias voltage drop was about 10V, put a little LM317 as a constant current regulator, and then repeat that as many times as I need until I have the right amount of LEDs. That way it would be super cheap. ~$20 for 50 LM317s, ~$20 for the power supply (unless you have them lying around like me) plus the cost of the LEDS and mechanical components.
for a regulated current of 350mA us a 3.6 Ohm resistor, for 750mA us 1.6Ohms

 

[kamko15]

Hey guys. Thanks for all the posts and advice, but I have a specific question I need help with.

if you look at the most recent diagram you'll see I'm planning on using

10 constant currant drivers to run each series of 7 LEDs in parallel. Okay got that figured.

Now I'm having issues with the power supply. I don't know how I am going to wire all of

Those currant drivers to one power source. please if anyone knows please reply.



Jim, I saw that my LEDs weren't the same currant and am now looking for replacements.

 

[Greg-ulate]

The LEDs not being the same current will not be a problem if you group the LEDs together by type and configure the constant current supply to provide exactly the right current for each type.

The Warm White LED from Superbrightleds.com looks like it provides 180 lumens for 3 dollars each @750mA, and the one on newark says 80 lumens for 8 dollars, that's less than half as much light for more than double the price.

the constant current drivers can all go in parallel with each other, as long as the power supply is capable of handling the sum of all the currents. I hope you don't spend too much on the current drivers, the method I suggested would require about 1 dollar each

 

[kamko15]

Hey guys I'm about to begin purchasing LEDs. when I'm all done Ill be sure to let you know prices.

But! alas i cannot move forward with this project, because I'm not sure how to wire all of the

constant currant drivers to the 24v power supply.I need to wire 10 parallel connections, and

for them to be parallel each driver will need to be directly connected to the power supplies

+ and - output. I haven't seen this done and am wondering if i just strip the + and - wires

then just "tie-in" or wire each positive and negative end of the driver to each singular

+ and - lead from the power source.

In my search for power sources I came across ones that said dual output. I am wondering if

I need multiple outputs, or if dual means it can hook up to two different arrays.

Please answer these questions specifically so I can begin to order a power supply.

http://www.kutop.com/power-supply/indoor-power-supply/120w-switching-power-supply-ac-to-dc-12v-24v.html

 

[kamko15]

LED SPECS

RED-1watt/2.0-2.6Volts/350milliAmps/40-50Lumens/620-630nanometers/120degrees

RED-1watt/2.0-2.6Volts/350milliAmps/40-50Lumens/660nanometers/120degrees

BLUE-1watt/450-460nanometers/3.0-3.6Volts/350milliAmps/15-25LumensM/120degrees





the attachment is the bill from the LED company. see how I did.

 

[NascentOxygen]

The constant current drivers can all be powered from a single pair of output terminals, provided the sum of the currents is within the current rating of the power supply.

I suggest that you fabricate only one current source to start with, and concentrate on getting it working and powering its group of LEDS.

 

[kamko15]

The constant current drivers can all be powered from a single pair of output terminals, provided the sum of the currents is within the current rating of the power supply.

I suggest that you fabricate only one current source to start with, and concentrate on getting it working and powering its group of LEDS.

Thanks for the reply, but could you be a little more detailed. Maybe you could you tell me if

the diagram with each driver separately tied into the output terminals is correct or if that's

not the right way to go about it.


Another question I have for all of the viewers. What gauge wire should I use.??

 

[jim hardy]

sketch on left is fine.

# 18 lampcord is easily good for 7 amps

 

[kamko15]

I recently got some help from customer service representative Deng Tianxiong of Kutop.com. He sent me

the diagram below, and said this was the method to wire parallel circuits to the power source.

Is the above diagram more correct than the method I was originally going to use

depicted in the diagram below?

In this diagram each LED drivers positive and negative leads are connected to the positive

and negative leads of the power source output. In Deng Tianxiong's however each LED

series is wired together positive to positive, and negative to negative.

You guys have been a great help so far and I am asking again for your help. Thanks in

advance!

 

[jim hardy]

Imagine it as a plumbing problem.

Supply pipes are red and go to positive of supply, by hook or crook.
Drain pipes are blue and go to negtaive.

The two drawings you propose are electrically equivalent, just one is a "star" or "Radial" hookup (all wires radiate out from one point)
and other is a "loop" or "daisy chain" where they are strung together like Christmas lights..

use whichever looks better to you and will be easier to repair when that becomes necessary.
Answer perobably depends on where you physically locate the supply.

 

[kamko15]

i wanted to keep all of the diagrams the same style so I made this one up.

I'm pretty sure this is what Deng Tianxiong's diagram would look like.

Please let me know if it is or not.

sorry I am not sure why but I couldn't resize the picture.

 

[kamko15]

Hey guys I havn't made a post in a while, but I have an update on this project.

I got all of the supplies I needed to complete the 70 WATT panel so I went ahead and did it

Looks pretty dam good you might say...WRONG!
I was really sure of my method so I wired everything up and never stopped to test, and this is what it got me.

I think there are two duds which doesn't say much for the quality of the LEDs, but besides that the series connections don't seem to be working.

heres a few close ups of how I wired them maybe someone could give me a little insight on how to fix this.

P.S. here is the power supply I am using maybe this has something to do with it as well.

 

[dlgoff]

Hey guys I havn't made a post in a while, but I have an update on this project.

I got all of the supplies I needed to complete the 70 WATT panel so I went ahead and did it

Looks pretty dam good you might say...WRONG!
I was really sure of my method so I wired everything up and never stopped to test, and this is what it got me.

I think there are two duds which doesn't say much for the quality of the LEDs, but besides that the series connections don't seem to be working.

heres a few close ups of how I wired them maybe someone could give me a little insight on how to fix this.

P.S. here is the power supply I am using maybe this has something to do with it as well.

Thanks for taking the time to report back.

I couldn't find any reference in the thread as to the wiring definition of the LEDs base terminals. (edit: oh wait. Yes there is. Let me read it first) Guessing here that the green "-" supply should be on the last LED in the string?

 

[jim hardy]

what's IN and what's OUT on your LED's ?

Clearly, current is only going through the first one of each string.

One of those wires from each constant current driver needs to go to LAST LED in its string...
so the current will go through all of them before returning to supply.

You had it right a couple weeks ago, , take a look at the sketch in your post of Feb1-12 11:49 PM.
Where's the wire going to last LED, that blue wire at top of panel? I thought you were showing it as 'typical " for all rows.
Looks like you hooked it to first LED instead.

Good thing you had that constant current driver in there !

 

[dlgoff]

Looks like your green negative supply should be on the last LED. Here's the diagram from your link, with my green and orange annotation.

 

[kamko15]

Yeah, Thanks for the replies guys I relized my mistake only after posting. I fixed the problem and am still having troubles so I am turing again to you.

here it is all fixed up

The electrical tape is only temporary.

Heres is it all Lit up.

Even though its not perfect yet, it still looks pretty cool. I also replaced the first two LEDs in line 10 and it is now lighting perfectly.

Problem 1- as you can see the LEDs in lines 1,2, and 8 are lighting but very dimly and I am not sure why.

Problem 2- line 9 is not lighting at all, like power isn't even reaching it.

Im not sure where these problems originate from or what could be causing them, but I need to solve these problems in order to move forward with this project. You guys have been a great help so far and I am hoping that you all have a bunch more advice to give.

P.S. It may have something to do with how the drivers are wired to the power source?

 

[NascentOxygen]

Good thing you had that constant current driver in there !

+1

The driver ICs have paid for themselves already!