I'm trying to build a LED set up for my 20"x20"x20" tank. Most of the rocks and corals are in the center of the tank. Should I space the LED 2" apart fom left to right and 3" apart from front to back? Will this spacing give me a "spotlight" effect?

Spacing is good. No spotlighting.

Thanks for the reply Evil. How many 3023-D-E-1000PmA Wired BuckPuck can i run on a 24V @ 6.5A POTRANS POWER SUPPLY? I also want to run (2) 12v fans on the power supply.

You can run up to 6 on that power supply. If you want to run the fans on the 24v power supply, you have to wire them in series.

Yes number 1 fan - goes to PS and + goes to number 2 fan - and + number 2 fan goes to PS. Is that right???????

Evil
I found a power supply from a old laptop the output is 19.5v 4.62a. I check the dc out put and its 19.4 with no load. Will that power the buckpuck? If so how many?

One more question..... If i order (1) 1000mA Constant Current Output, External Dimming W/ POT. Can order (3) 1000mA Constant Current Output, External Dimming without pot and wire all 4 to that same pot?

Thanks

You have your series wiring correct.

That power supply will only let you run 4 LEDs per driver, so it may not be too practical. You can run up to 4 1000mA drivers on it.

For the drivers, you will want to order one 3023-D-E-1000P, and three 3023-D-E-1000 Buckpucks. The "P" on the end adds the pot, but the rest will still be wired, just no pot.

Ok parts are in except for the power supply.

Evil I got questions

1. When using Arctic Silver to attach the LED. Do i spread the adhesive all on the back side of the starboard or just a little bit in the middle?
2. Do I just twist all the wires from the buckpuck and attach to power supply? ( I think that parallel )
3. Are the drivers better off near the LED or power supply or have both the ps and drivers near the LED?
Thanks in advance
Kenny

how many LEDs is that? Looks like 28? Will that be enough?

1. Either or. Just make sure its a thin layer once the LED is seated.

2. Yes

3. Near the LED is preferable, but you can put them wherever makes the most sense to you. Just make sure the wire size is adequate.

ok got the LED mounted and wired. Each puck is running 6 LED and powered by a 24v power supply.

I first measure the voltage from the power supply and i get 22.8 volts then i measure the draw on each string and i;m only getting 580-613mA with the pot turn all the way per string. I thought the puck i ordered with power the string at 1000mA ?????

Even at 600mA these led are very bright.

You need to adjust your voltage on the power supply (assuming that you have one of the MPJA units). Adjust it so that it is above 24v. With the voltage at 22.8v, the driver can't regulate the current properly, which is why you are seeing it low.

any ideas??? I tried to adjust the white knob and i can adjust it down to 20.3v and up to only 22.6v ???

It's the standard 24v 6.5A Potrans power supply right?

Yeah it's the 24v 6.5A Potrans power supply and what a dummy I am. I didn't switch the input voltage from 230v to 115v. It's putting out 900mA now. What is the best way to adjust and where should the output voltage be?

The coverage and how bright these LED are crazy. Here are a few pics of the puck all solder up and 24 LED over my 120.

Question
1.What is the best way to adjust the voltage (with a load or without) and where should the output voltage be?

2. I am going to build more LED for the 120gal 48"x24"x24". Will the spacing of the led change? Will i do something different for the 120 gal and not the 20"x20"x20" cube??

The voltage switch helps a lot

1. You should be able to measure the power supply voltage with no load. These switching power supplies are pretty good at regulating the voltage with and without a load. You don't want to be measuring the output voltge of the driver, other than to check that everything is working. The driver voltage is dynamic based on the needs of the LEDs, but won't change much with dimming.

2. Everything gets put together the same way. Just more of it

ok so spacing the leds are the same? Also I'm just doing softies with a few LPS. You think 60 led will be ok to cover the 120? Also will you run optic lens?
Thanks

60 won't be enough. 90 would be a better number (18x5). 60 degree optics will be a good idea for a tank that deep.