Introduction: 108W LED Grow Light Panel

Picture of 108W LED Grow Light Panel

This is my first instructable, I hope you all enjoy it and hopefully some of you will get some use out of it.

Growing with LED lights

Using LED lights for plant growth is a nice alternative to using HPS and metal halide. While many argue that the results are simply not the same in recent years LED's are slowly gaining respect in the indoor plant growing community.

+Uses up to 80% less energy on your bill making it a green solution.
+Lower heat and easier to control temperature.
+Long life span up to 50,000 hours
+Precise spectrum for photosynthesis

The main disadvantage with LEDS is the cost of certain high end units. This instructable is here to give those that are interested in plant growth with LED's a nice cheap alternative DIY solution.

Step 1: Tools and Materials

Picture of Tools and Materials

+Soldering Iron
+Wire stripper
+A little series/parallel wiring knowledge

+Cooling fans($6-$20 or salvage)
+Thermal glue ($7)
+Nuts + Bolts ($3)
+2 - 3 feet of 18 AWG wire (3$)
+Metal Panel 7"x7" from ($16)
+Led Drivers x 3 (36$)
****use bulk rate because you get a disscount when purchasing 3 or more****
+DC transformer 8-14V (salvage)
+AC power cord/plug (salvage)
Total: $110-120

LED's from Ebay(about 40$):
3W Blue x4  (455nm)
3W Blue x4  (445nm)
3W Deep red x16 (660nm)
3W Red x12 (630nm)
***you dont have to use the same configuration as me, try your own let me know how it works out for you***

Step 2: Drill Holes

Picture of Drill Holes

The first step is to drill 6 holes for the led drivers and 1 hole for the wire to go through.

+Use a ruler to find the approximate centre of the led drivers when they are next to each other.
+Take a marker and ma

rked the six holes where to drill for the led drivers.
+Then mark one hole for the wires to go though (look at pic which will show you where to place it).
+Time to drill the holes
+First drill the six driver holes using a drill bit that is about the same size as the bolt
+Then use a bigger drill bit and drill the hole for the wires
+When finished you should have a metal plate similar to the one in the picture below

Step 3: Glue the LED's to the Panel

Picture of Glue the LED's to the Panel

In this step you will mark the placement of where each LED will go

+This is easy, measure one side of your panel, take that measurement and divide it by 6
+Now for me this came to about 1.16"
+Now use a ruler and place a dot every 1.16" on both that side and its opposite, once you are done this connect the dots and you should get 6 rectangles on the panel.
+Next you do the same thing to the other 2 sides of the panel and you are left with 36 even squares and should have a pannel that looks something like the picture bellow.
+After that we will mark where each LED will go (or you can use my picture as a reference, or you can make your own configuration)

Step 4: Glue on the LED's

Picture of Glue on the LED's

In this step we will attach the LED's to the panel

+Simply take the thermal glue apply a little to each led and stick it on the panel
+Add moderate pressure and twist slighty to spread the thermal glue and get a good surface contact
+MAKE SURE THAT LED's TERMINALS ALL FACE THE SAME WAY (+) and (-) unless you are doing your own configuration
its not a big deal if you mess up but prepare for some messy wiring

+wait a couple of hour or overnight for the glue to harden and cure

Step 5: Soldering

Picture of Soldering

+Once all LED's are in place and the glue has cured it is time to solder the LED's
+ I did this in rectangle shapes but you can solder it any way you want as long as you solder only up to 12 LED's in series.
+If you are unsure what series wiring is just simply google it, but in the simplest way to describe it to you is simply always solder the + terminal onto the - terminal of each individual LED so that every LED will have only two connections and will look like the picture below.

+Cut a piece of wire the length of one terminal to the next, and use the wire stripper to strip away a small portion of the end of the wire
+For easy soldering add a little solder to the terminal before adding the wire
+then simply re-heat the solder and solder the wire onto the terminal and your final product should look something like mine

+Once your have finished that, you then solder the + and - terminals of each driver to each of the 12 LED's in the series circuits and should have something that looks like the last picture of this step

Step 6: Bolt on the Drivers

Picture of Bolt on the Drivers

In this step you will bolt on the drivers on to your LED panel

+first take each bolt and use the nut to secure it to the panel
+after this add another nut close to the top of the bolt
+do this for all 6 bolts and it will resemble the picture below
+then add the driver on top of the bolt and tighten the last bolt to hold the driver in place
+do this for all 3 drivers

****the main reason behind raising the drivers of the panel is to add air circulation to the panel and drivers for heat manegment***

Step 7: Power to the Drivers

Picture of Power to the Drivers

In this step you are simply adding a 120V or 220V plug to your drivers

+take a power plug salvaged of anything thrown out
+Solder the matching 3 AC blue wires from the drivers together and to one of the plugs wires
+after this do the same for the other 3 blue wires
+I used electrical nuts or whetever you call them to simply screw the 3 blue wires + plug wire together for both AC wires
+also if you wish to add any switches I recommend that you add it to the AC line and not the DC ( for example you can add 3 switches to power on and off each individual series of 12 LED's)

****I used a retractable AC power cord this is totally unnecessary, it is simply the cord that I had available at the time and will most likely change to a regular cord****

Step 8: Cooling and Mounting

Picture of Cooling and Mounting

This last step is really up to each individual user to determine how they want to approach

+because most people have spare PC fans it is perfectly fine to use those or any other fans available to you
+I personaly used a fan I bough from a second hand electronic store for $6 and it works quite good
+ as you see in the picture this type of fan nicely pushes air along the surface of the plate cooling down the whole plate

+you can add any type of cooling you like just remember that you will need a external power sourse to power your fan/fans
+I used a salvaged transformer to power my fan simply connect the + and - terminals of the DC transormers to the mattching terminals of the fan/fans(require parallel wiring) and there you have it

****cooling is extremely important it is never a bad idea to add a thermal switch to the main LED circuit in case your fan circuit fails****this panel can reach dangerous temperatures without cooling and can become a fire hazard use at own risk*****

 remember that this panel will produce a fair amount of heat, keep this in mind along with the fact that some plants require up to 12 hours of constant light

How you mount your panel depends on where you will mount it, I personaly am going to use the bolts of the drivers to mount my panel onto a cabinet shelf, this will be included in my next instructable as I tend this to be part 1 of MAKE an automated arduino garden

Step 9: Finished

Picture of Finished

Thank you
I hope you have enjoyed this instructable
If you have any question feel free to ask me I will answer them when I can
If you made one enjoy your panel


GoonyLex (author)2016-06-29

I'am not sure why a bunch of you are getting flashing LED's. I have so far build a bunch of these panels (most are retired now) and none had flashing led issues. I have not revisited this in a while but off the top of my head to me it seems you guys might have a component mismatch. The drivers are constant current so they are more stable than a simple linear supply. Because they are constant current they do need to have specifically 9-12 leds that are 3W.

Here is what might be happening:
1. You are not meeting the correct Voltage and Current draw requirement.

2.This will cause drivers protection circuit to activate.

3.The driver will turn off

4.Moments later the driver will restart and try to power the LED's again.


Check your components

PhillipW18 (author)GoonyLex2017-05-03

Were your blue leds 3.2-3.4 FV and your reds 2.0=2.2 FV???

IvánO36 (author)2016-04-21

The guide helps build only 30% or less. Since the data presented in the instructions are very incomplete, the measures are incorrect.

I recommend a lot of research before buying goods or start building this lamp.

westexjoe (author)2016-04-14

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I'd like to caveat everyone on a condition that may be
overlooked. Even though the each LED is supposed to be electrically
isolated from the bottom of it's PCB, don't count on it! Leakage of
any magnitude can lead to a wide range of results, most are not good
if multiple LEDs happen to be leaking to others on the same heat
sink. If this happens you may or may not see any symptoms or failures
right away. Be warned. DO NOT ALLOW the bottoms of the 20mm PCBs to
leak electrically to other LEDs nor to the power bus.

So if you are
experiencing LED failures, that's the FIRST thing to check for. I no
longer use adhesive for holding the LEDs to their sinks. I apply an
additional insulating layer (electrical tape if you have to) and
firmly hold the LEDs on their heat sinks using mechanical means.
Once an LED has been subjected to overheating, it will have permanent
damage and can't be expected to last it's normal lifespan with the
expected optical output levels.

adam.notneeded (author)2015-02-21

Anyone else have an issue with that driver flashing? It seems like it takes anywhere from 5 secs to 3 mins to stop flashing and stay on.

hey, I just got the same issue, but my light already works about an hour and 2 of 5 drivers are flashing... how did you solve the problem?

Sounds like a resistance issue... LEDs require resistors to prevent strobe like effects. Just don't ask me what resistance is required for this particular setup cuz I'm not an expert either. I'm sure google would point you in the right direction though. And resistors are cheap, so it's not an expensive fix.

Quoting someone else who actually is a pro (Jason Poel): "With the resistors, you have to keep in mind the wattage rating. Most resistors are either rated for 1/8 watt or 1/4 watt. This refers to how much power is dissipated in the resistor itself. To choose a resistor you use: R = (Vsource - Vled) / Current(led). To find the wattage dissipated in the resistor: W = (Vsource - Vled) x Current(led)."

Hope this helps.

Nielsd (author)turgsh01.2016-04-04

For my LED grow light project i used seperate constant current drivers behind a step down mains power supply. I had a problem with my lights flashing because the rush-in current was too high (Charging constant current driver capacitors is effectively a temporary short), overloading the mains power supply max current and made the overload protection kick in. Which resulted in continued flashing.

ElizabethR19 (author)2016-02-15

There are different types of led: the bulb like with two long wires, tiny squares with no tabs and sold in strips, etc

Is there a name to the particular type of led used in this tutorial?

ShetalB (author)ElizabethR192016-02-18

The LED grow light market is expected to rise to more than $1.9 Billion by 2020, growing at a Compound Annual Growth Rate (CAGR) of 26.93% between 2015 and 2020.

ElizabethR19 (author)2016-02-15

What would I salvage "cooling fans" from? Is it possible to use higher watt leds?

ianm45 (author)2015-12-30

The LED drivers listed have a lifespan of 15,000 hours. Where does the 50,000 hour lifespan you listed come from?

KhaiR1 (author)2015-10-20

actually,i'm going to this thing for my final year project..I would ask some question regarding this project..Firstly,can i know the power sources that u are using? because i'm using AC power sources 240v.Then, do you have circuits for this project?

Then, for my final year project i may need to design something rather than just buy and use it.So,i'm planning to design the LED driver or the transormer..For your opinion which one is easier to design?
Thanks Sir.

evone (author)2015-08-28

Like is there a certain amount of red, white and blue lights needed to make this work? How many red verses white and blue? Do they have to be put in a certain sequence? Ahhhh I am so sorry I know all of these questions have probably been asked before. Thank you so much for all the info you have already given. I am so excited:)

RaphaelS11 (author)evone2015-09-24

have a look above for an answer :)

RaphaelS11 (author)2015-09-24

for people asking about what light frequencies are best and how much of each should be had this should be an interesting read:

John L (author)2014-12-18

I have a question that I have not seen asked yet. Per your instructions you used two types of Red and two types of Blue LEDs. Why is this imperative? Why can't I use the Warm White(2700k-3400k), and Cool Daylight White(5600K-7000K)? It seems to me that this would be a better overall way to go, since its really combined frequencies in order to produce the white light.

ideamaster (author)John L2015-03-19

Because the red and blue light are the main frequencies that plants crave. If you use white lights. You are losing energy to the rainbow. ROYGBIV. You can use white but you are pumping out energy to 5/7ths of the colors that don't provide a lot of value.

evone (author)ideamaster2015-08-28

Okay so... how big of an area are we talking as I only see one plant, and should the room be covered in foil or other reflective material to make a few lights seem like more to the plants? I am such a newbeeee at this but I am moving onto some land and want to do aquaponics inside.

SkillP (author)2015-08-06

Hi. I am planing to do a 25 W (true wattage) DIY LED panel and going to use these leds

How many of those each you recommend ?

kwdaily (author)2015-03-13

Hey awesome 'ible. I was just curious how did you determine that your spacing was sufficient. I am designing a 10" x 10" x 0.375" aluminum panel to hold 100 LEDs, and as of now I that leaves then on 1" centers. I plan to use thermal paste/glue to attach and am using an array of heatsinks on the back, plus fans circulating over the whole assembly. How big are the drivers you used? Dimensions wise? Thanks for the help, my questions are more for anyone who can answer then anyone specific. Whew, typing tirade over. Thanks guys.

GoonyLex (author)kwdaily2015-07-28

Um I probably dident use the best spacing as I did no prior research regarding the topic. Sometimes to get stuff done you just gotta try it.

MyreneD (author)2015-04-20

Hi there!

I need to get my red LED plant grower light to intermittently turn on and off in order to stimulate collagen production etc, what can I use on the cord? I will be shining this light on my knee and hip but I understand that it need to flash on and off to produce any noticeable effects. Please, help I am planning to visit my son at the navy and hope to be able to hike in the mountains near the base.

Thank you,

GoonyLex (author)MyreneD2015-07-28

Hi buddy
There are many ways to do this, the simplest way would be attach a relay to an arduino and make a simple program to control the relay. Here is a simple example

If your not into programming and doing the wiring yourself Im sure there is an purchasable solution but you will have to do a bit of research to find it.

xyrius (author)2015-04-09

So I wanted to double this in size and went with 14" by 7" and there is no way I can fit even the normal 108 watts of LEDs, let alone 216W -_-

ALSO, anyone find a good way to keep the power cord mounted in place firmly? I looked at using a U-bolt but that doesnt keep the wire secure, simply off of the panel :/

As for cooling im using two 0.18A blower fans, but having a hell of a time finding a power supply that is 400 mA and not 25$ on ebay any ideas?! Cheers guys cant wait to load up some pics once I finish the build

P.S. my plate is only 1/8, rust resistant aluminum, very sturdy but will they prove to be a deep enough heat sink? Do I need to buy something closer to 1/4? I do have two 1/8th plates i could slap together to bring it closer to 1/4th but im unsure at the moment!

AdrianL2 (author)2014-10-29

I know there are many critiques here in regards to price and other nit picks, but all in all, you did a great job in making a basic DIY LED grow light that will work. I made mine a little more "sophisticated" using qty100 1w LEDs. I configured it in array that would evenly distribute the UV and IR evenly. My choice of color and qty are as follows:

54% Red 660nm, 20%Red 630nm, 16%Blue 470nm, and 10%Blue 425nm, all with 60 degree beam angles.

I keep it about 14"-18" away from the top of my plant, and I did add mylar around the perimeter so light would bounce everywhere. So far, my plants have not complained one bit about being confined to a closet.

I may just bump up my next one using 3w LEDs and get a ton more usable light, but for now, my plants and I are content. Keep up the good work!

kwdaily (author)AdrianL22015-03-13

How exacctly did you arrive at your percentages? I am doing research on optimum wavelengths, trying to nail down a design for a LED panel myself.

gbekks (author)2015-03-09

I just made this and have a similar problem as others. My light is pulsing at different frequencies for each driver. I ordered what you recommended but i'm sure they could be different since our projects are two years apart. Did anyone have success trouble shooting this?

xyrius (author)2015-02-19

what kind of cooling fan is that? all cpu fans i know are square, i cannot find anything similiar to this :/

Also do you wire the drivers all together (black and white seperately of course) and then just wire directly into the power supply cord?



adam.notneeded (author)xyrius2015-02-21

The long fan is a type of squirrel cage fan.

xyrius (author)adam.notneeded2015-03-09

So I wanted to double this in size and went with 14" by 7" and there is no way I can fit even the normal 108 watts of LEDs, let alone 216W -_-
ALSO, anyone find a good way to keep the power cord mounted in place firmly? I looked at using a U-bolt but that doesnt keep the wire secure, simply off of the panel :/

As for cooling im using two 0.18A blower fans, but having a hell of a time finding a power supply that is 400 mA and not 25$ on ebay any ideas?! Cheers guys cant wait to load up some pics once I finish the build

P.S. my plate is only 1/8, rust resistant aluminum, very sturdy but will they prove to be a deep enough heat sink? Do I need to buy something closer to 1/4? I do have two 1/8th plates i could slap together to bring it closer to 1/4th but im unsure at the moment!

forex5x (author)2014-04-06

Would it be possible to use a power supply from a recycled computer to drive the LED's?

WayneO2 (author)forex5x2015-01-16

I'm sorry, but with 18 leds and only a 12 V power supply, the leds would be in 6 stings of 3 leds in series (approx 10V) each set of 3 leds in series would need a 2.2 ohm resistor also in series. the six strings, with their resistors, would all be connected in parallel... the only catch would be that each string needs 900 mA and there are 6 strings... that's 5.4 amps and you have only 5 Amp power supplies...

the resistors are necessary to allow the strings to evenly share current, else the string with the lowest combined forward voltage would "hog" the bulk of the current and the rest would be "starved".

The resistors would also need to be 1 watt each.

The ideal drive would be a single string of 18 leds driven by a constant current power supply set to 900 mA (this would require a total string voltage of 59.4 V)

WayneO2 (author)forex5x2015-01-05

Yes, this can be accomplished, but you will have to add the appropriate Constant-Current regulator(s) to insure that the LED's are not over-driven.

glen.raymond1 (author)WayneO22015-01-16

Do you know how to make it work 18x 3W Red (630nm) in serie with 18x 3W Blue (445nm) on a 12v dc 5amp power supply? (i got two 12v dc 5amp power supply)

GoonyLex (author)forex5x2014-04-12

yes it is possible, however you will require an additional circuit to control and maintain a constant current.

glen.raymond1 (author)2015-01-16

How to make it work 18x 3W Red (630nm) in serie with 18x 3W Blue (445nm) on a 12v dc 5amp power supply? (i got two 12v dc 5amp power supply)

micgreen (author)2014-12-25

waow, the hotline still here since 1 or 2 years? Bravo ! (i'm french, sorry for my english). A little first question for you goonylex : is it possible to put drivers out the panel (for heatless, moistureless and practicable)? Like a ruban wire and mollex connector(s) one meter lenght ? Must i have bigger section of wire between (molex) leds and drivers ? Thanks a lot.

micgreen (author)micgreen2014-12-26

oups, mistaking : this little question is't only for the author but for the experts too ! Sorry mr. Watergunz and Adrian...

Watergunz (author)2014-11-07

Just got done making this Instructable, amazing!

I must say heat is an issue here from the LED's not the drivers, please use a cooling system to lower the temperature for sure!

GoonyLex (author)Watergunz2014-12-10

Good Job! looks good :) happy growing

axmejo (author)2014-12-03

Hi. One array of leds pulsates att about 3hz. And another barely makes the LEDS glow. I have the mentioned drivers from and 3W leds from eBay going from 2.2V to 3.2V I'm perplexed by this. Anything give a clue?

GoonyLex (author)axmejo2014-12-03

with no load what are you measuring coming out of the drivers?

axmejo (author)GoonyLex2014-12-07

Hi all three drivers push out between 59~61 V dc

GoonyLex (author)axmejo2014-12-10

that is strange then, try measuring the resistance between each individual led to see if you find any resistance variation that might point you to a bad led. If that does not work send me a link to what you purchased.

Fitchett (author)2014-11-11

If you hook up the LEDs (per driver) in parallel instead of series:
1.) Would it still work?
2.) If one LED went out, would the rest of them on that driver continue to work?

gofasteddie (author)2014-08-15

Are you powering 12 leds with each power supply?

Watergunz (author)gofasteddie2014-11-08

Yes he is powering 12 LED's with each driver.

GoonyLex (author)gofasteddie2014-08-20

Yes each driver supports 9-12 Leds.

jjosef86 (author)2014-09-25

how close can the leds be? i want to put 150 3W leds on a panel. what size panel would be ideal?

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