60W 30€ Dimmable LED Grow Light

!! Working with electricity could always be dangerous, so be careful and protect yourself! If you have no experience in working with electricity learn the basics first.!!

We like growing things. As we want to grow plants like pepper,tomatoes or pumpkins, we have to start most of our seeds indoors. To give them a head start, we built our own cheap LED grow lights to enhance plant growth and to get healthier plants.

3 Challenges:

Cheap:

We searched for the cheapest components with good quality to make our project feasible for a small budget.

Efficient:

LEDs consume much less energy than conventional lights, but that was not enough. We also made sure to use red and blue LEDs with the right wavelength to maximise efficiency

Fanless:

Heat is a big problem for LEDs but because of the usage of a large surface and thermal glue, it was not necessary to mount a fan.

Step 1: Materials

14 x LED RED (650-660nm): (50 pieces quantity) http://goo.gl/s9AR3Z

2 x LED Blue (450nm): http://goo.gl/sgWZDn

4 x LED White (6500K): LED WHITE http://goo.gl/5jwCHt

24 V Power supply 60W: http://rover.ebay.com/rover/1/711-53200-19255-0/1?ff3=4&pub=5575141758&toolid=10001&campid=5337762987&customid=&mpre=http%3A%2F%2Fwww.ebay.com%2Fitm%2FLED-24V-2-5A-ADAPTER-POWER-SUPPLY-60W-%2F141636620626%3Fhash%3Ditem20fa335152

2 x LM2596 DC – DC Step Down Converter: 1 http://rover.ebay.com/rover/1/711-53200-19255-0/1?ff3=4&pub=5575141758&toolid=10001&campid=5337762987&customid=&mpre=http%3A%2F%2Fwww.ebay.com%2Fitm%2F5Pcs-Output-1-23V-30V-DC-DC-Buck-Converter-Step-Down-Module-LM2596-Power-Supply-%2F321476590827%3Fhash%3Ditem4ad97f7ceb

Metal sheet 800mm x 150mm:

Thermal glue

Screws

Cables

= 30€

Tools:

Soldering Iron

Drill

Wire Stripper

Cutter

Solder

Step 2: Idea

Plants do not require the full spectrum of light. The wavelength with the best absorption rate is between 450 - 480 nm (blue) and 650 – 700 nm (red). To save energy, we only use these two colors and just add small quantities of white light (full spectrum). Nobody knows, what the best configuration is and to be sure that our plants get enough light we added these white LEDs. This works fine for us, but you can test your own configuration if you want to.

Step 3: Preparation of the Metal Surface

At first you have to clean the metal sheet and the backside of the LEDs. It is important that the surface is free from oil. therefore, use a bit of alcohol.

Draw helping lines on the metal for the right positioning of your LEDs. This will help you a lot in the next step.

Step 4: Gluing

Use the thermal glue and glue all LEDs to the metal surface. You can stick to our plan or test your own configuration. Do not use too much glue. A thin layer is better than too much glue.

Step 5: Drill the Holes and Place the LM2596

Drill the holes to place the LM2596 as well as one hole in every edge to be to attach the light later were ever you want to. Mount the LM2596 to the surface.

Step 6: Change the Output Voltage (dim) of the LM2596

Solder the power wires to the LM.. Use a multimeter to check the output voltage. One LM should have 19.6V (for blue and white LEDs)and the other one 15.4V (for the red LEDs) You can change the output voltage by screwing the screw on the blue element on each LM2596.

Step 7: Soldering

Do the soldering, stick to the plan. If you have no experience in soldering, please learn the basics first. Otherwise it is possible to harm yourself or the building parts. So be cautious!

Step 8: Does It Work?

Connect the growlight to the power supply and check whether it works. Now you can install the lights wherever you want to.

I hope you have enjoyed this instructable. If you have any question feel free to ask me. I will answer you as soon as I can.

Comments

[TinaG82]

What size area will one of these lights cover? How far away do you place your lights from the plants?

[mschroeder14]

were your LEDs effected (fading light, burning out, etc.) buy not having any heat distribution?

[zyzu]

Question does this LM2596 give u a constant current of 350ma I don't wish to damage my leds

[zappenfusen]

Resistors for protection of Leds might be a good idea. 1 ohm resistors were made for this.

[Team Z]

You could be right, but we trust in the LM2596. Until now, we have no problems with this issue. Of course, if there occur problems, we will let you know ;)

[zappenfusen]

At the price of the LEDs replacement would be cheap but have you ever heard of thermal runaway? I know nothing about the LM 2596 but Led drivers offer current control as well as voltage which with solid state devices is pretty important. Are y'all located in Sweden? Instructables has gotten huge in the past few years. In the town, State, Nation I call home you start ordering the items on your parts list and you start hearing strange clicks on your phone line. Nah, I ain't paranoid but found out the hard way the authorities call growing "manufacturing" with a possible 10 year hiatus from life as we know it.

zapp

[Team Z]

We are not located in sweden ;). Our arrangement works fine. Please inform youself about the LM2596, it is also called "buck" and I think it works similar to an LED driver. We regularly control temperature which is always very acceptable. Don`t try to grow illegal plants and there is no need for you to be paranoid or afraid I think :D

[zappenfusen]

What? Me worry?

[zappenfusen]

Don`t try to grow illegal plants and there is no need for you to be paranoid or afraid I think :D

Ah to be a member of the Great Society of "Earth People". We common folk driven by base desires blaming actions on basic lack of control will one day be deemed non-essential and the birth of a drug free, Utopian society will finally dawn. Ingesting the green stuff may be a little rough though! All people are created equal, some a little more equal than others though. Like pigs.

zapp

[Najn_arte]

I was thinking, if I use a Christmas LED light string with the blue, red, and white LED lights instead of soldering, would it work? I am just thinking it could be a no-soldering method, although I would still have to glue the lights to the metal plate. What do you think?

[Team Z]

not a good idea, you need the right wavelength.

[bcLong]

Trying to put together my own plans but I'm new to electricity. My thinking was that I need a direct current driver for my leds but you're only using the step down converter. So if I want dimmable leds do I still need the direct current driver? Or does the step down converter do everything?

[Team Z]

The step down converter does everything.

[Zheka163]

Prompt brand hot glue with which you have pasted the LEDs? I never heard of such a glue. More interested in a current consumption you get and how you can use the LM2596 make it stable for LEDs is very important.

[milkcartonkid]

last I knew blue was the main color they need for growing and your only suppose to introduce red to start the flowering and grow the fruit or vegetable. over all nice nice instructable :)

[Team Z]

Thank you =) Yeah I have read something similar, but nearly all grow lights you can buy have significantly more red LEDs. I think there `s still a lot of research to be done to figure out the best configuration. It is also true, that different plant species prefere different wavelength. Because of those uncertainties, we`ve added the white LEDs. There are so many meanings about what is the best configuration and all meanings differ. Would be great to have a reliable source. We have also built 3 slightly different grow lights varying in power consumption and LED ratio, but all with more red than blue. I think because life developed out of water, plants are so good in using blue light. But as soon as plants began to grow on land, they also started to use red light. Aquarium lights should just consist out of blue LEDs, I think. All in all, complicated topic and a lot possibilities to try out.

[milkcartonkid]

just tryin to help you out, ive always used blue florescent bulbs. but is there any chance you've checked how much power it uses per hour?

[Team Z]

Currently, we are running the grow light at the lower end of the voltage area, to test a few things out.

P = U*I

2.2V*0.7 = 1.54W (red LED)

3.4V*0.7 =2.38W (blue LED)

3.2V*0.7 = 2.24W (white LED)

All in all: 35.28 W ==> 0.03528 kw/h

[andb41]

Hello I'm planning to built a similar grow kit but i'm confused with the power supply. What is limiting the current?

thank you for your instructable

[milkcartonkid]

look under the right color

http://www.gardeners.com/how-to/gardening-under-lights/5080.html