I've been meaning to replace the T8 lights on my tank for a while now but never cared enough til I realized that it wasn't enough to grow HC. I've been talking to Darren about doing an LED fixture for his ADA tank but decided to wait to see how it compared to a T5HO setup. This is my first time I've posted a DIY on one of my projects and was too lazy to use my heavy SLR so it's gonna be a bit messy so bear with me until I can finish and clean it up. Introduction -
I'm using my Via Aqua AR-680 18 gallon tank that I picked up on craigslist to see how well it will grow HC. This is a complete hood system which has integrated filtration and lighting. It uses 2x 15watt T8 Biolux tubes and the pump is pretty strong and quiet enough for my bedroom. I've had it up and running since October and it seems to be growing Dwarf Hairgrass and Christmas Moss okay but isn't enough for my HC to carpet. I'm using a 5lb CO2 tank diffused by a Hagen Mini Elite and using a bag of Eco complete and Black Sand as my substrate. This is my tank with the default T8's right now. Materials - LEDs
Cost - 13 x $3.24 + Free Shipping = $42.12 DealExtreme.com
I used 13 Cree XR-E Q2 LEDs because it was cheap and put out a decent amount of light. According to Cree these LEDs should last you about 50,000 hours or 5.7 years, beats having to change T5 bulbs once a year...
PLEASE don't use those 5mm LEDs that you find at Radio Shack or Ebay, those are tiny, inefficient, expensive and you'll just end up wasting tons of time wiring everything.
You should use Luxeon III or K2, Cree P4 or Q2-Q5, Seoul P4, or those ultra expensive Cree MC-E. These LEDs come in 3 diffrent colors Cool, Neutral, Warm so take a look at the color chart . The kind they sell at DX is Cool White. These run at 3.7v 1000ma
Volts * Amps = Watts
3.7V * 1A = 3.7W * 13 LEDs = 48.1 Watts
The Cree XR-E has a 90 degree beam so you might want to use a narrow Optic Lens to focus the light more if you got a tall tank. I decided not to use any until I see how effective they are without a lens.
I've included a picture of my DIY Lightsaber which uses a single Luxeon K2 Blue LED which was running on a set of low AA batteries to show you how bright a single LED can be. Since this is a blue LED it doesn't appear as bright as other colors and it is also being filtered through a ton of gift wrap paper to diffuse to light more evenly.
Here is a bit of random information I picked up from a LED Grow Light explaining Why blue seems dimmer then other colors...
"Our eyes are most sensitive to the middle (green) part of the visible spectrum and sensitivity decreases toward the blue and red. Plants on the other hand respond most to red and blue and little use for the middle part of the spectrum and is why chlorophyll appears green (green light is reflected not absorbed")
I would love to add some blue LEDs to my setup to give it that actinic look but for now its just gonna be white...
The Q2 puts out 87 lumens at 350ma and the Q5 puts out 107 lumen but we all know that lumens is a terrible measurement of how much usable lights the plant can use...
I'm not sure how much PAR this setup will produce but from what I read on other DIY LED Guide it should be atleast equal to a T5 setup of equivalent Watts. LED Driver
Cost - $30.99 + $9 Shipping = $40
This is a Meanwell ELN-60-48 LED driver which will drive 13x 3w LED and is alot easier to use. There are other versions of this driver that have dimming capabilities ELN-60-48P & ELN-60-48D but those are a lot more complicated to use and cost more. You can also use a 1000ma Buckpuck which will safely power up to 6x LEDs but require you to find an appropriate transformer. I chose the Meanwell because it was cheaper and didn't require a transformer.
This driver runs at 60 watts 48 Voltage 1.3 Amperage but has a knob that you can turn to reduce it by 25% to 975ma Heatsink & Aluminum Plate
Cost - FREE or $5-$20
Luckily I found some aluminum heatsinks and a plate I had left over from my PC watercooling project from a while ago. The aluminum plate is completely optional and the only reason I'm using it is because I didn't have a large enough heatsink. It would be better to just put the LED directly on the large heatsink but I only had 3 small ones. Thermal Compound
Cost - $5-$13
I used the cheapest tube I could find at Fry's Electronics which was the ceramic kind at $4.99. You can use the expensive Artic Silver 5 but I think it is a waste on a project like this. Screws
Cost - $5 ???
I had alot of these screws in my tool shed and they were the right size so I decided to use them. You should get a box of Nylon screws for securing the LEDs to the plate but I ran out and decided to just be really careful Wires
I strip and tin a bunch of wires for soldering to the LEDs Assembly - Measurement and Drilling
First step is planning everything out carefully. Take as long as you need to make the precise measurements, and mark everything down. Take your time when you are marking the places you are planning to drill on the plate. It took me a couple of hours to drill that plate in the picture Thermal Compound & Heatsink
After making sure the heatsink fits proper apply a VERY THIN layer to the heatsink. I applied WAY too much in the picture below, PC Geeks must be cringing at that picture lol. Applying too much thermal compound will make the heatsink less effective. After you spread it out evenly carefully screw the plate on. LED Mounting
Next step is to mount the LED. There are many different layouts you can use, some being more effective at covering a larger surface area while others focus more on light concentration. Since this is a retro fit I didn't have much of a choice and just used a basic layout 1 inch of space between each LED. I hope you took your time when you made your measurements because it would be a pain the ass going back to fix a mistake. Also when you screw the LEDs to the board make sure to align it so that it is + then - then + see picture below. Don't forget to use a small amount of Thermal Compound on the bottom of the LED star. LED Wiring
Now the next step is to solder the wires in SERIES which means - then + then - then + ...
Ok thats all for tonight I'll continue to update tomorrow!