Help me position LEDs

[catchprj]

I have 48 LEDs on their way from RapidLED. There are 24 CW and 24 RB with 4 drivers. I have 60 degree lenses included in the package.
I also have 10ft of aluminium U channel to use as a heat sink (to be cut up however necessary).
I have been trying to think of the best way to lay out the lights to cover my tank while providing some high, and lower light areas.
The issue is the stupid shape of my tank - it is a pentagonal corner tank:

What would you guys do?

 

[Egkid]

I would do 4 strips of 12 hung parallel with the front of the tank.

 

[catchprj]

Would you suggest alternating rows of CW and RB so that I can control each strip with a different driver, or alternating LEDs?
e.g:
Strip1: CW CW CW CW CW...
Strip2: RB RB RB...
Strip3: CW Cw Cw...

OR

Strip1: CW RB CW RB...
Strip2: RB CW RB CW...

 

[Egkid]

From what I've read if you do one strip all CW and another RB you'll probably have bands of blue and white in your tank. I alternated mine like your second example and have no problems.

It may be a pain to wire the blues and whites on seperate drivers (which I highly recommend) if you alternate them though.

 

[catchprj]

What do you think about this setup? The extra 6 LEDs would go over my small frag area in the sump.

Is this a waste of LEDs i.e. do you think the extra 6 will be needed over the tank, or is 42x 3W CREEs enough? - it is 70gal, 22 inches deep.

 

[brassmonkyballs]

What do you think about this setup? The extra 6 LEDs would go over my small frag area in the sump.

Is this a waste of LEDs i.e. do you think the extra 6 will be needed over the tank, or is 42x 3W CREEs enough? - it is 70gal, 22 inches deep.

I think that would work well and 42 is plenty. The extra 6 on the small frag tank is good but make sure you include blues otherwise you will wash out the colors. I assume you plan to use fans to cool the channel.

 

[catchprj]

I ordered the constant current kit so will have 2x Mean Well LPC-35-700 drivers and 2x Mean Well LPC-60-1050 drivers.
It would be nice to have some control over the level of light, so I thought I would wire the CW LEDs from channels 1 and 3 to one driver, and the CW LEDs from channels 2, 4 and sump to another driver, and the same with the RB LEDs. This way I can set the [2, 4, sump] drivers to turn on in the morning, then the [1, 3] drivers to turn on a little later, then turn off in the reverse order.

Does that sound like a reasonable idea?

Also, do you think the 60 degree optics will be necessary? The LEDs will be mounted ~8 inches from the water surface and the water is 22 inches deep.

 

[brassmonkyballs]

from an intensity perspective no you won't need them...the problem becomes you don't have dimming drivers so you cannot turn it down...I would not use them but put it up without them 1st...i think you'll be surprised. If you put them on your output goes up dramatically.

 

[brassmonkyballs]

from an intensity perspective no you won't need them...the problem becomes you don't have dimming drivers so you cannot turn it down...I would not use them but put it up without them 1st...i think you'll be surprised. If you put them on your output goes up dramatically.

I would like to add that some people wonder why they bleach everything with LEDs or that they don't get the colors on their coral like the should....my experience has been from over lighting and too much white. I really wish you used dimming drivers.

 

[catchprj]

This may be a silly question so excuse my electrical ignorance... Is there no way to dim the LEDs on a constant current driver? I dont plan on doing it, but in theory could you wire a variable resistor in series with the LEDs to increase the resistance of the circuit, and hence supply less power to the LEDs?

 

[brassmonkyballs]

This may be a silly question so excuse my electrical ignorance... Is there no way to dim the LEDs on a constant current driver? I dont plan on doing it, but in theory could you wire a variable resistor in series with the LEDs to increase the resistance of the circuit, and hence supply less power to the LEDs?

nope.....the dimming drivers have a feedback loop back into the driver via a couple wires to which you hook either/and/or a 10v supply and a potentiometer depending on the driver.

 

[catchprj]

Ok... next question! haha
I am trying to think of the cleanest way to wire the LEDs, especially with the alternating CW RB pattern. Here is a diagram of two options I have so far...

Just looking at the RB diodes, the first option would have a straight wire going between each RB diode. It would mean overlapping wires once the CW were wired as well. (I don't like this option as much as the second).
The second would involve drilling into the aluminum U channel (either drilling through the side or base of the U) and running the wires through the middle of the U. I think this option would be much cleaner, however I am not sure how important air flow will be through the U and/or how much the wires will disrupt this flow. I see others on ReefCentral have mentioned that the LEDs barely get warm with a heat-sink like this, and that they don't even need a fan to cool them... I am a little more cautious though.
Any thoughts?

 

[brassmonkyballs]

Ok... next question! haha
I am trying to think of the cleanest way to wire the LEDs, especially with the alternating CW RB pattern. Here is a diagram of two options I have so far...

Just looking at the RB diodes, the first option would have a straight wire going between each RB diode. It would mean overlapping wires once the CW were wired as well. (I don't like this option as much as the second).
The second would involve drilling into the aluminum U channel (either drilling through the side or base of the U) and running the wires through the middle of the U. I think this option would be much cleaner, however I am not sure how important air flow will be through the U and/or how much the wires will disrupt this flow. I see others on ReefCentral have mentioned that the LEDs barely get warm with a heat-sink like this, and that they don't even need a fan to cool them... I am a little more cautious though.
Any thoughts?

If you drill through just make sure you debur the hole so it doesn't cut the wires and cause a short. I have not drilled. I just cross them. I use full heatsinks and they get hot without fans but I push my LEDs. just run them on the bench for a couple hours and if the aluminum gets hot you have your answer....won't hurt anything long term.

 

[catchprj]

Thanks so much for your help! You've been awesome!

 

[brassmonkyballs]

Thanks so much for your help! You've been awesome!

keep us posted on progress!