DIY led lights for 210 gal

[Funkness]

Ok guys and girls recently aquired 210 gallon tank and I want to use led lights on it only thing is never been experienced with LEDs the tank is 7 ft long and I will be building a canope for it but I have no idea how many what watts what controllers or heat sinks to use any ones experience with this would be awesome also should I build one long led fixture or two smaller ones?

[Timfish]

Lots of variables! What is going to be easy to work around when you are doing maintenance? For myself I like either doing a bunch of cannons that I can point in different directions and angles or something almost full length so the tank is evenly lit. That's what I like about LEDs is they can be relativley easliy customized to your tank. Keven B and Jason Jones have good threads on multicolor builds. I'm attaching three .pdf files of DIY stuff I've done.

ARC 34 Watt LED Cannon.pdf

ARC LED Cannon 60 watt.pdf

Cree XP-G light field.pdf

[Funkness]

I am liking the cannon idea hmm would the 5w instead of the 3w make any difference in the design ? Also how many of the PVC pipe design would you think I would need I was thinking 2 to the front of where the two built in over flows would be and two on each sigh of the support making it 6 all together and mounting to a canope hmm

[Timfish]

My motivation for the cannon design was to replace some 250 MH on some of my tanks. Taking some light measurements I need 2 80 watt cannons to get comprable PAR reading as the 250 watt MH fixtures I'm using. The heat sink I used for both the 34 watt and 60 watt cannons is supposed to handle 90 watts so I don't anticipate a problem running 8 of the 3 LED stars in this design. The reason we only needed a 60 watt cannon to get fairly similar PAR readings on the Solana was the reflector for the Solana is basicly a cylinder which wastes a lot of light. The Cree LEDS with both designs are running at about 2/3rds of thier maximum current rating so you could squeeze out more light by running the XP-G CW (and /or NW or WW) at 1500ma and the XP-E B/RB at 1000ma. LEDSupply.com caries 1400MA buckblocks. Meanwell also has several drivers that will work well. You will shorten the LEDs life expectancy running them at max current.

There are very different conditions to consider using dc powerd (or low valtage ac) buck pucs or buck blocks versus drivers that use 120 vac like the Meanwell drivers. Using the buck pucs or buck blocks I can run just a single 24 - 32 vdc line to the cannon and can actually chain cannons together as long as my dc power supply will handle the total current. One thing I like about this is I don't have 120 vac close to salt water which greatly reduces the risk of dropping something in the water and getting shocked (well, actually it only reduces the risk of getting shocked ) . The disadvantage is dimming is more complicated since seperate control wires would have to be run. On the other hand it is easy to put a thermostat between the dc input and the buck pucs or buck blocks which will turn them off if the fixture gets to hot from a fan failure. This is more complicated using drivers like the Meanwell drivers as you now have to run a seperate ac line to the thermostat and back to the ac input of the driver.

You do not want to put a thermostat on the output side of any driver unless you have carefully matched the LEDs to the max output of the driver. Most LED drivers initiall apply a minimum voltage and current to the LED circut and increase it untill the current is at it's design rating. This allows you to use one or several or many LEDs without worrying about figuring out the current and voltage drops across the LEDs. If a LED driver does not sense a load on the output it will end up with the maximum designed voltage and current on the output. If a thermostat cools down then connects a string of LEDs to the output and the string has not been matched it will run the string at maximum voltage and fry some or all of the LEDs. Of course if you want to sit down and figure out the voltage and current drops across a string of LEDs you can dispense with a driver and just use regulated DC power supplies and current limiting resistors and I will think you seriously need a life .

RapidLED.com also has a nice heat sink that is tapped and drilled to accept either thier single LED stars or another manufacturers 1 or 3 LED stars. It is possible to put something together that will pretty much fry anything you put in your tank (with very narrow lenses I was getting PAR readings comprable to sunlight around 3:00 with the 60 watt cannon!). I would encourage you to sit down and do some simple drawings and calculations to get an idea of just what you need and how you want to lay it out. It is easy to do to much or not enough.