Introduction: LED Grow Light Using Illumitex Surexi F1 LEDs

I wanted to build an LED Grow light with real Horticulture LEDs(designed with Wavelengths for Photosynthesis)

I did not want to use Rope Lights or regular Blue LEDs or Red LEDs.

Illumitex makes fixtures and also sells the LEDs($16 for a 16 LED package) through I bought some LED packages and a few power supplies as a test. Read on for what I found out and Romaine Lettuce growth.

Step 1: Backstory

I wanted to see if the Illumitex LEDs were any good before buying a Fixture through a Distributor.

You can Buy the Illumitex LEDs packages off Mouser for like $16. Search Mouser for Part number AD446S-500F1

Then you have to get a 500mA Constant Current Power supply. I screwed up on my 1st two purchases but I am now using LCM-40U from Mean Well. (Make sure to size the Output voltage right for how many LED packages you plan to drive)

Power Supply Selection tips

-Input Voltage - make sure you do not get one that is 180VAC and up(i found one that met my Output Current and Output Voltage, but was High Input Voltage)

-Output Current - 500mA is called out on LED datasheet, do not exceed

-Output Voltage - Range needs to meet the amount of LEDs you plan to have in series 11V for 1 package, 22V for 2 packages in Series and so on(I bought and Returned one that met Output Current but the Voltage range was too high for only 2 LEDs)

Step 2: Collect Datasheets

The First Document shows the Voltage and Current requirements of the Illumitex Surexi LEDs.

One Package needs approx 11V and 500mA. (Later I found forward voltage to be less and also changes as LEDs warm up)

The 2nd Doc from Illumitex tells you how to Solder to the LEDs. Which is harder than you would think(or you just need to follow their instructions and use a 60W Soldering Iron!)

I also attached the LCM-40U Power supply Datasheet. It has DIP Switches to set upper Current Limit. You can also hook up a Potentiometer to dim the LEDs. Its output Voltage range is (2-70V at 500mA DIP setting)

I also got a APC-25-500 from Mean Well, its cheap and Fixed Current of 500mA. You need a minimum of Two Surexis in series to meet output Voltage range of (15 to 50V)

Step 3: Solder to LED Package

Read the Install and Thermal Guide from Illumitex. It stinks these files are not on their Website anymore. I found them through Google.

You Need a 60 W Soldering Iron and Solder on something not Metal or Thermally conductive.

The Aluminum back of LED package will heat up during soldering, but you don't want to suck that heat away or the Pad wont be hot enough to solder.

I used 22 Gauge Solid core wire from Radioshack. My solder job isn't pretty but I was pretty frustrated having to buy a 60W iron when my 40W was not working.

I have the LEDs, clipped to piece of Aluminum DIN rail, eventually will mount with Screws.

Step 4: Wire Power Supply and LEDs

I have two LEDs wired in series. I used terminal blocks to connect them in series and to the Power Supply.

Make Sure to Set the Power Supply DIP Switch Setting for 500mA. 700mA is default, do not smoke your new LEDs.

I used Term Blocks so I could test for Amp draw by wiring a Meter in series(why there is an extra block). Also I might add more LEDs cause power supply can go up to 70V.

Step 5: LEDs Work(getting True Leaves Now)

So I had my Romaine Lettuce seedlings chilling in back room since Dec 18, they put out their 1st leaves but no True leaves till after I turned lights on. I had lights on all day(7am to 5pm) on 12/24, then off for 12/25 and 12/26 cause I left. I came back to a 1 true leaf on most plants but it was stringy cause I left lights off for 2 days(I didn't expect this to happen)

Now 2nd true leaf is coming out.

Check out photos of how Leaves stand straight up at End of Day(lighting session)

Then they flatten out next morning when light is back on. That's Crazy that plants move based on light. No motors or muscles!