So I have been asked to do this a few (hundred? )times now, so I figured I would get it out of the way. Hopefully this will provide some education to those looking to dabble in the world of high power LEDs.
If you asked for this, here it is. If you didn't, well you're getting it anyways
Go grab a cup of coffee, hit the bathroom, you are going to need it. Don't worry, I'll wait.... Back? Ok. This is a lot of information, but it's useful. Making educated decisions on how to build your LED array will save you time, money and headaches in the future. Put it this way, I did all the hard work for you. You just have to read it.
DISCLAIMER: This involves the use of tools that can hurt you, and electricity that can kill you. Please be careful. We would like to see you back here again showing off your new LED setup at some point. Missing limbs and burned off eyebrows won't get you bonus points. I have tried to explain everything here as clearly as possible and as safely as possible. I hold no responsibility for you hurting yourself or others.
First things first. This will be addressing high power LEDs only. 5mm, 8mm, and 10mm LEDs are just not powerful enough for most applications. There are some instances (like fuges, algae scrubbers, and very small pico tanks) where they can be used, but when it comes to most applications, they don't cut the mustard. I will be writing up another thread addressing the differences between the different sizes here soon.
Many of you have posted question on this forum like "I want to get into LEDs, but I don't know what to get", and "I know what parts I need, but I don't know how to wire them up". These are the kind of questions that will be addressed here. I'll divide this into three parts; "Why Use LEDs", "Parts You Need", and "How To Put It All Together".
This article will be updated continuously as new tecnologies and part options become available. It will also be updated to correct any goofs that I make. Hey, I'm not perfect
Update History
2-17-09 Initial Release
3-17-09 Added Recom driver to the driver list
3-25-09 Added Meanwell ELN series drivers to the list
Why Use LEDs
We have all seen LEDs before. They are everywhere in our society in all kinds of modern technology. But why use them in our aquariums?
Up until recently, we weren't able to use them effectively to light up a tank. Too expensive, and just not powerful enough. But in recent years there have been great advances in the area of high power LEDs. Now, what makes a high power LED different from those that we find in our electronic devices?
First thing thats obvious is the amount of power used. Typical high power LEDs come anywhere from 1 watt to 3 watts, where your average 5mm LED is around 1/4 watt or less (8mm, 10mm and Superflux LEDs can go as high as 1/2W). With this high power comes increased brightness, but also increased heat. This increased brightness, which is many times more than 5/8/10mm LEDs is important for penetrating the water to greater depths. Another advantage is that they can generate more light over a wider angle. This is a clear advantage over smaller LEDs, as usually manufacturers will make the angle tighter to generate higher brightness numbers, and are usually so tight that they create what I like to call a "spotlight" effect, which it basically is. Currently, the top end high power LEDs are right behind metal halide and T5 in terms of efficiency, so you can produce almost as much light (lumens) for the same wattage.
But producing light, lumens in this case, is not what LEDs are all about. The real clincher is the ability to produce more PAR (Photosynthetic Active Radiation) per watt than most any other form of light. For those that don't know, PAR is a measurement of the amount of light that falls onto an area, that falls on a response curve for photosynthesis (400-700nm, ignoring UV and IR light). Basically what this means is that more PAR equals more growth out of photosynthetic corals. Because of this, LEDs do not have to produce as many lumens as other forms of light to reach the same growth potential. This also means less power is required too.
The next major advantage is heat. Now, I'm not going to say that these LEDs don't produce heat, as they do, and quite a lot of it. But what makes this different is where the heat is radiated from. Usually in most lights, heat is emmited from the bulb itself in the form of infrared light. LEDs do not emmit infrared from the emmiter and will not directly transfer heat into the tank like a metal halide bulb would. The heat that is generated comes off the back side of the LED. Usually, they are mounted to heatsinks to effectively control the heat, and radiate it into the air. Without additional heat placed into the tank, there is now less of a need for chillers and additional fans to cool the tank, saving you money.
LEDs can also save you money long term by elliminating bulb replacement. Most high power LEDs are rated to live for 50,000 hours before the light output drops to about 70% of the original rating. Thats a long time. With a light schedule of 10 hours a day, these LEDs could effectively last for over 13 years! The price you pay upfront is going to be more, but it could pay for itself within the first few years of ownership.
Another benefit of LEDs is the fact that they can easily be dimmed and controlled. Can you imagine being able to change your color temperature on the fly, going anywhere from 6500K to 20,000K? It's pretty cool. I realize that there have been new prducts released recently for T5 that allow dimming control, but I'm sure at quite a cost. Controlling LEDs can actually be quite simple, but also allows for some more complex setups and effects that you simply can't do with any other lighting source.
So as you can see, there are some very compelling advantages to using LEDs for aquarium lighting. The upfront costs will be more than most lighting setups, but the savings long term between heating and cooling costs, running costs (ie. less power to operate, less equipment to run), equipment costs (ie. removing a chiller out of the equation), and maintenance cost (bulb replacements) can make up the difference is a short period of time.
So how do you get this going?