Hi.
I'm building an LED upgrade for my marine tank and it is made up of 3 sets of 12 LEDs. On each array is 6 x Cree xr-e cool white Q5 and 6 x Cree xr-e royal blue group 15. Could I please have some help on selecting the correct drivers, power supply and controller to be able to simulate sun-rise, sun-set and various other functions like cooling fan controllers.
Many thanks.
You are gonna need a pretty beefy power supply, all those LEDs will need a total 12.6 amps (350mA each for nominal brightness). I would look into a 5V 100W supply should be more than enough.
I take it that these are already prewired into modules? Are the modules built with seperate inputs for white and blue?
So, assuming you are just trying to simulate natual sunlight, I'm assuming there is no need to vary the lighting individually (by color or module). Essentially you need one output controling the brightness as a function of the sine of the 'altitude' of your simulated sun. You could of course make very complicated formula simulating a particular latitude or simulating 'seasons.'
I don't know if anyone has any experience with how well an Arduino keeps time. You might want to consider a RTC, otherwise you might find that 'sunrise' doesn't occur until noon.
Well i'm building the arrays myself. Mounting the LED's onto 3 200 x 180 mm heatsinks and using pc fans to cool them.
http://www.ultimatereef.net/forums/showthread.php?t=400993&highlight=led+build&page=2
I found this thread. Do you think I could re create that kind of control for my set up?
Should be fairly straight forward to duplicate this.
I'm going to have to do some calculations but each LED is 350mA @ 3.2V, that's all of 1-1/8 W times thirty-six LEDs works out to about 40W total. It seems to me a large heatsink and forced-air cooling is overkill.
Everything about that design seems a bit overkill, but sometimes that the point
Get yourself a 24V power supply and three of the those dimmable BuckPucks (700mA) version. Run each module with six LEDs in parallel. Simply use three outputs of the Arduino (you got 'em might as well use 'em) to control the BuckPucks. I love that they have a 5V output for the uC.
My only concern is electricity, metal, and salt water don't mix well. So, you gonna have to take care and protect the uC, wiring and connectors, and the metal heatsinks from the corrosive effects of salt water contamination. (and yeah don't drop the whole setup in the tank :o)
Thank you so much for your help.
So do you think that 1000ma buckpucks to drive the white LEDs is overkill?
You could certainly use 1000mA constant current supply since you will be capable of dimming them. I made the assumption you were going to run them at their nomial IF (350mA) instead of maximum. Running them full on will shorten their life, but it wouldn't be unreasonable to design that capability into them. You just can't mix LEDs on the same circuit if you do.
I've read the post in the other forum and I still wonder about some of the numbers he is using. Such as 15W/in2 for lighting. That sounds awfully high for solar insolation. The typical number I see is 1kW/m2 or about 0.65 W/in2. With his numbers, he should have 16KW of lighting, thank goodness for the fishes sake he divides by 13 instead of multiplies. The pictures of the aquarium look properly lighted, so somehow he seems to have ended up with a reasonable amount of light.
Assuming the numbers of LEDs per area is correct, you could get three 1000mA and three 700mA dimmable sources. To handle this you would need at least a 150W power supply.
Mugzee, in case you didn't found it yet, have a look at this arduino powered reef controller http://reefprojects.com/wiki/Main_Page (details and code included)
Greetings,
EriSan500