Introduction: An Even "cooler" LED Grow Light

Picture of An Even "cooler" LED Grow Light

hello everyone,

please support & share our mission;

today we will be putting together yet another LED grow light. a much cooler one..

cooling down grow lights are still the biggest issue, whether HPS, CFL or LEDs. most of the space usually goes towards this problem with either of these system. most of the cost also is created towards the solution, fans. lots of them..


LED grow lights have already proven themselves easier to cool down compared to other methods. my previous design; had to use fans to cool itself, due to the lack of a proper heatsink.

This time however I decided to use proper heatsinks, making the project fanless - also freeing up an outlet.!! new design is also more powerful, 12W to 16W. capable upto 20W using the same amount of space.. a huge improvement.



- 3x heatsink;

- 4x 660nm 1W;

- 4x cool white 1W;

- 4x warm white leds 1W;

- 1x led driver;

- 1x metal sheet;

- 1x ac cable;

- 1x switch (optional);


this new design is 16W, ~34V @350mA. it is $10 to operate 18hrs/day x365 days. and even less since there are no fans used anymore.

let's build>

Step 1: Measure

Picture of Measure

i need to be able to hang the light, and adjust its height as needed.


for this we need to make a frame first. I cut a piece of thin metal sheet using a drill and rotary cutter.


you could "glue" the heatsinks side by side using metal epoxy for your specific design. I could use a little distance between each light source..


i designed the cuttings in such a way that we should be left with nice little holders in place.

Step 2: Cut

Picture of Cut

first i used the drill to make lots of tiny holes along the cut lines, in pursuit of less rotary cutter time.. you can go either way for a cleaner cut.


after you cut the lines, bend the little flaps upwards using plyers.


it is going to be a tight fit, slowly try to place the heatsinks into the holes. make sure to cut less at first if you arent sure about the dimensions, you can always go back and cut more. much easier to fix..


Step 3: First Trial

Picture of First Trial

also drill 4 holes for the carrier wire.


attach some garden wire to each hole and hang where needed..

Step 4: Wiring

Picture of Wiring

here is the wiring diagram of the LEDs, solder everything in series.


using very little thermal glue place each led on the heatsinks. these heatsinks are supposed to work with 5x 1W LEDs. 24/7 x365days ON.


however I chose to use 4W/heatsink to get better cooling, and left the middle of each heatsink empty as I may upgrade to 5W/heatsink in the future.


there are many heatsink options out there, you can get

single 1W heatsink;

or upto +20W heatsink;

using them side by side etc, one can design a very effective and sleek grow light.

Step 5: Conclusion

Picture of Conclusion

the heatsinks do get warm, as i leave them on for long periods of time.. i am yet to test the actual temperature with an IR thermometer. will update here once done.!


i am in the process of updating box1; - i need a simpler, a more sleek look. allowing more space left for what really matters, plant growth.


I will be making more prototypes using other styles of heatsinks available as well, subscribe to stay updated. I also am going to try to use peltier thermoelectric cooler/heaters.


love & peace



Kuffy (author)2017-02-23

Hi Akin! Great Work , thank you!

I failed at buying the right led driver, instead I bought 18V - 700mA.

How could I use this driver withe 1w leds ? I tried looking online but did not understand how to do it :(

Anyway good luck with your projects and keep up the good work!

Akin Yildiz (author)Kuffy2017-02-25

hello, sorry for the late response :/

1w led = 3.5V @350mA since you are using a 700mA you have to add the 1Ws in parallel to reach 700mA. and since its 18V, you also need to add 5 of them in series. (18/3.5=5)


so what you need to do is add 5 1W leds in series, and make 2 of these. then connect these 2 strips together in parallel. which will equal to 18V 700mA :) 10LEDs total, 10W, equal to 90W incandescent.. pretty strong tiny light source.
here is a quick diagram. this is electricity 101. if you add in parallel, current mA goes up, if you add in series, voltage goes up. hope this helps

RobinP55 made it! (author)2016-06-02

I made this for my carnivorous plants. They soil always needs to be wet hence the bowl with water integrated in the design. Next up is an automated watering system :)

Akin Yildiz (author)RobinP552016-06-02

wow cool.!! how many lights you got there :)
thank you for sharing, great stuff.!!!

JakubB10 made it! (author)2016-04-14

Finally, after few months of waiting for parts, rebuying good parts instead of wrong ones, one or a few resolderings of leds, this Project is complete. Big Thank You to Akin Yildiz, who made this great guide, and hand on hand guiding me through problems, i am now happy, and girlfriends is happy, thank you Akin :)

Akin Yildiz (author)JakubB102016-04-14

i'm speechless, amazing work..
what is the frame made out of.?!

JakubB10 (author)Akin Yildiz2016-04-14

Actually the frame was bought long time ago by my girlfriend, and since we didnt have enough light in our apartment to grow anything in it, it layed useless for some time.

Akin Yildiz (author)JakubB102016-04-15

great stuff, glad you guys are getting a use out of it now :)

remember to put books under your pots to bring the plants closer to the light, and slowly remove books as they get taller/older
and please take pictures during growth and share it here later on.!!!
thank you for following this post,

JakubB10 (author)2016-02-22

hey Akin, it is me again, unfortunately, my heatsinks got lost in the mail, and i have to order new ones, do you think this cheap black ones will be good, or better to take this silver ones?

Akin Yildiz (author)JakubB102016-02-22

the look identical, either should be fine. can't tell without actually trying/feeling the material, but both say aluminium.?! good luck this time, i always purchase on

JakubB10 (author)Akin Yildiz2016-03-10

Hey, one last question, i have all the parts finally, but i am thinking about glueing radiators to the plasticy-glassy walls of this plant house, but i am wondering if hot glue would hold. How much the radiators heat up? Would the hot glue hold? I am planning on 5x1W leds on a 6x6x1cm aluminium radiator.

JakubB10 (author)JakubB102016-03-10

And do i have to bend the wings upward? Or can i leave them like they are and they wont conduct through radiator?

Akin Yildiz (author)JakubB102016-03-11

you HAVE to bend the legs up. it will conduct and shock/fire all kinds of bad stuff. you can NOT touch those legs anywhere, and after soldering you should seal them with hot glue as well.!!!!
and yes you can hot glue the radiators to the plastic housing, it will hold up, just try to do a good job and get a good layer of glue from all sides. you'll do fine :)

JakubB10 made it! (author)Akin Yildiz2016-04-06

Hey akin, i have last question before my project is complete. how would you wire this 4 modules? parallel or in a series? my driver is 20-40V and 900mA suitable form30W. Leds are 1W each. i want to ideallymhave 2x2 modules because they each will have their own hanger

Akin Yildiz (author)JakubB102016-04-06

very nice.. easy stuff.!!
1. you have to wire all 4 modules individually in series
2. you wire 2 of them in series together,
3. now you connect these 2 in series modules together in parallel.
ask me if you don't understand.

JakubB10 (author)Akin Yildiz2016-04-07

Well, something is wrong, cause i plugged it in, and it doesn't light up. I have 42.6V on each module, and between main + and -
What could be wrong?

Akin Yildiz (author)JakubB102016-04-07

how sure are you that each individual LED you have are placed on the board to face the correct + & - leads to each other. you have manually placed them on the pcb boards, are you sure you have lined up the legs correctly.?!

JakubB10 (author)Akin Yildiz2016-04-07

Every thing is clear :) I will try to upload my photos today after i finish

JakubB10 (author)JakubB102016-04-06

i mean i have 2 hangers and on one hanger there are gonna be 2 modules (5Wx2)

JakubB10 (author)Akin Yildiz2016-03-11

And if i use this star like bases for leds i dont need to do that right? Just solder leds on the base, glue the base to radiator and solder wires between the leds?

dylan.ochala (author)2016-02-11

Is it possible to create a 100W light?

Akin Yildiz (author)dylan.ochala2016-02-12

yes it is possible. you have 2 options for a 100W light.

1. ready to use with regular AC plug. no fan or heatsink required due to design. also comes with reflector and attachment system. this is a VERY good light.. get warm white and cool white..

2. make your own.

- light;

- heatsink;


since the final price of either option is very close, i would rather choose option 1 as it will be much more durable and tested. however those only come in cool white and warm white. to add more spectrum you can use these chips and make your own;


the problem over 3W LEDs is that now you are talking about serious cooling issues. you have to have the rightsize heatsink and most likely a fan with a DIY light. they will both work great.!! give it a try

dylan.ochala (author)Akin Yildiz2016-02-12

Awesome. Thank you. I am going to build this one first and then move on to that. Would it be possible to wire x10 10W in series and make 5 rows of these totaling to 500W? I am in a winter crop class, and we have these 500W full spectrum light bars that I really want to see if I can't design and build my own for cheaper!

Akin Yildiz (author)dylan.ochala2016-02-13

yep, you got the idea.. LEDs have surpassed any other light source out there years ago. it will be much better than what you have right now.!! give it a try and document with picx.
thank you for your interest

dylan.ochala (author)2016-02-11

Just ordered all the parts! Going to build this soon. Will post some pics. Thank you for this excellent guide.

Akin Yildiz (author)dylan.ochala2016-02-12

great news.!! remember to document it with pictures.

K-Greenhalgh (author)2016-02-01

Hi I did my own version of this project and used these LED's

2 X 430

2 X 660

2 X cool white

2 X warm white

the LEDs are connected to an LED driver and my power source is 3 X 9v batteries. I also have a two pronged switch connected to the batteries and to the LED driver except the LEDs are not lighting up. Any suggestions?

Akin Yildiz (author)K-Greenhalgh2016-02-01

can you show me a picture of your LED driver. i believe what is happening is that your driver is AC to DC driver. and you are trying to power it up with a DC battery. this option will work but you will need the right driver. this is why I need to know what driver you are using. can you please share a link/picture.


you also need to explain your wiring. are they in series, the batteries and the lights. i need more info

marsdefends (author)2016-01-04

I am inspired by your work & have decided to get into this.

Went to karakoy (yes), bought 30 LED's, 30 star bases, 2 drivers & 6 heatsinks. I'm pumped & ready to go...EXCEPT the thermal glue.

First, they are so expensive in so little packages (Even more expensive than deep red LED's) do you know a good place to buy in Istanbul by any chance?

Second, what would be the alternative to thermal glue? I read online that some people mix superglue with classic thermal paste, is it a viable solution? what would you advise?

lastly, some of the heatsinks have a cheap looking thermal sticker on it, the thickness of the sticker must be around 0.1mm and doesn't cover all the star-bases (as shown in the picture)

Am I being too cautious? or should I stick to the safest path and spend extra and buy the glue?

thanks a lot.

Akin Yildiz (author)marsdefends2016-01-04

technically you do not need thermal paste. you can just use nuts&bolts;

but this way you will need to drill holes. as long as you have a clean wide surface area for the heat transfer everything will be fine. are your LEDs 1W or 3W.?

also it looks like you have led beads and little base stars separately. you will need thermal paste for under there however.!! all you need is very little, like extremely little, less is better. put a VERY tiny thermal paste and push it down hard while turning the light left and right to spread it out evenly. use very little, allow it to dry overnight.!!

you can find more info and ideas here;

let me know how it turns out.!!

franksey (author)2015-04-16

Great tutorial. I would like to build this but have two questions first:

Is this setup suitable for growing herbs from seeds? (Basil, Thyme etc)

And, do I need to make any adjustments with the electronics to ensure it works when attached to the mains (I live int he UK)?


Akin Yildiz (author)franksey2015-12-16

wow i can't believe that i have missed this comment.. did you get it sorted out.? so sorry,

yes this setup is suitable for herbs but honestly you can grow anything under this light. i currently have a citrus tree that is 3yrs old - from seed


nope, the led driver i use is 100-240AC universal, you can use it right away safely.

JakubB10 (author)Akin Yildiz2015-12-18

Hello, i have a question.
I would like to make this light from 4 heatsinks, 5 LEDs each 1W.
How many of each LED colour do i need to have the best results? (Basil, lettuce, thyme maybe some flowers), and how powerful of a driver?

Akin Yildiz (author)JakubB102015-12-18

how big is your grow area.?

JakubB10 (author)Akin Yildiz2015-12-19

i have 3-4 pots with max diameter of 10.5 cm. I grow in this thing from swedish furniture manufacture
I want to make it from 4 heatinks, so i can bend in the middle and mount at the roof of this thingy, so it looks nice and as clean as possible

Akin Yildiz (author)JakubB102015-12-19

pretty much something like this you have in mind. each of these plants have a heatsink with 5x3W LEDs on them. user tiunkabouter below shared his work.


if you use 1W leds then you won't need fans, and it will be a low profile light. there are many ways of going about it. i can draw you a schematics if you want..

you would need 1x 40V @700mA LED driver and can use 8x warm white, 8x cool white, 4x 660nm red. each light would have 2x warm, 2x cool and 1x red. you would connect 2 of these light together in series. and then 2 sets in parallel to a single driver. or leave them seperate with their own LED driver.


i can draw you a wiring diagram once i get home. i wasn't able to open the ikea link btw

JakubB10 (author)Akin Yildiz2015-12-20

i would be thankful for the diagram and wiring schematic. Thank you for your time

Akin Yildiz (author)JakubB102015-12-20

all LEDs are 1W. they are all connected in series going into the 1st LEDs + positive out from - negative to the next LEDs + leg exit - leg, and same until end.. total of 20 leds, 2 drivers.

whites are cool white;

yellows are warm white;

reds are 660nm;

drivers used, 2x

heatsink is same as this instructable, make sure to use thermal paste as listed above.

JakubB10 (author)Akin Yildiz2015-12-31

i dunno why, but my last reply didn't pop up. I want to use one driver, would 30w/900mA be enough?, and in that case i need to connect red to red to driver and black to black to driver?

Akin Yildiz (author)JakubB102015-12-31

it came up and i replied :) you must have not seen it, here;

Akin Yildiz (author)JakubB102015-12-19

there is something that has to be mentioned. you said you would like to grow basil, lettuce, thyme and flowers. all of these except the lettuce will require a very minimal setup, see attached picture. i have 1W and 4W with a single tiny driver+plug.
but for lettuce you will need much more light, 5W per lettuce is probably the bare minimum. since we will be harvesting food from it. so also let me know about this as well..

JakubB10 (author)Akin Yildiz2015-12-21

i might let lettuce go for something else if it doesn't work out.
I want to use one driver, so i need to connect it in prallel, so red to red to driver, and black to black to driver?
Also as you wrote before, 40V, >700mA ?
would this one do:
it is 1200mA,

or this one verison 30w 900mA is better? it is twice the price

Akin Yildiz (author)JakubB102015-12-21

yes exactly, both of those lights in parallel can reduce the number of led drivers needed. and like you have mentioned, now we need a same voltage but 700mA driver this time. waterproofs are nice.
good luck and please remember to document & share your work.!

tiunkabouter (author)franksey2015-12-07

1, probably

2, LED drivers accept 110-250v AC with 50-60Hz so it should work fine

franksey made it! (author)2015-04-25

Thanks to Akin for all his help—I've made a version of his grow light for three herbs in the kitchen.

Akin Yildiz (author)franksey2015-12-20

do you have an updated picture with some growth inside, i have this as an example, made it for a friends kitchen, you can see it in the background, the triple pot version, only 4W

Akin Yildiz (author)franksey2015-04-25

wow very nice :) i really like the clean/simple design.. looks like it is bright enough to light up the entire kitchen.

which heatsinks are those, im assuming that you glued 3 together.?

one advice however, if you have a hot glue gun, you may want to seal each soldered connection. it's in a kitchen, water may splash or smtg.. also make sure that none of those connections are touching the heatsinks.


this is very exciting, thank you for giving it a try !!

franksey (author)Akin Yildiz2015-04-28

I got three of these heatsinks and used epoxy to bind them together: Usefully, the heatsinks have drill holes along the sides so I could actually just nail them into the wooden frame easily.

It is bright yeah, but I've also added some other herbs around it to make use of the light somewhat.

Thanks—will cover up the soldering to make it safer!

tiunkabouter made it! (author)2015-11-23

build one for my square foot garden (60cmx60cm/2ftx2ft)

the 4 units are composed of 5x 3w CW, 3x 3w WW and 2x 3w RED
each unit is adjustable in height, and have removable 90 degrees lenses

Akin Yildiz (author)tiunkabouter2015-11-23

amazing work. this 30watt system equal to about 270watt (1000+ total) output. without adding the benefit of focus lenses. plants must be in heaven :)


feel free to share your harvest as well, thank you.!!

About This Instructable




Bio: Please support & share our mission; . the Plant Doctor is a non-profit, open source online research laboratory specializing in electronics+plants. Our vision is ... More »
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