DIY LED Questions

[richardhmc]

Howdy! I want to make a DIY led fixture and I have some questions.

I'm trying to figure out whether or not I want dimmable drivers. I plan to use 36 3w Leds (white and blue) over my 50 gallon tank (36 x 18 x 18). At the last swap, I recall someone saying that for them, the power of the LED was too strong and that once they dimmed the intensity, they had better response from the corals. Is there any truth to this? Is it worth getting dimmable?

Also, my 50 gallon has a center brace. Should I split the 36 LEDs half and half over each opening of the tank? Or just use one long heatsink and stick them all on there. The LED fixture will be only about 5 inches off the water, which I was told that I don't even need lenses since they are so close to the water.

Thanks!

 

[smoq]

Hey Richard, I'll give you some advantages of having a dimmable leds vs. non-dimmabe:

-first of all, obviously, is that you can dim them. In my and few other people I talked to opinion, dimming them really help corals adjust to the light. I experienced some montis bleached after being exposed to the full power of leds and I needed to move them away from the top of the LR, but when I dimmed thee light they were OK on top
-second and IMO strongest advantage is that you can control the temperature of the light by simply dimming the blues and whites to your needs. Thats a good reason to have a dimming circuit
-third of all, sometimes you need to dim the leds a little bit so they don't run too hot. I found out that if I dim my white leds just a slightly little bit (I guess form 1000mA to 900mA) the heatsink temperature goes from warm to touch to completely cold
-other than that, if you have or will be planning to get a controller like Apex you would be able to create interesting effects like sunset or so

If your 50g has a center brace I would not use lens on the leds that are right above it or do two fixtures. That's what I did, I have a 36" tank and I'm using two 24 leds fixtures. Hope that helps

 

[richardhmc]

Hey Richard, I'll give you some advantages of having a dimmable leds vs. non-dimmabe:

-first of all, obviously, is that you can dim them. In my and few other people I talked to opinion, dimming them really help corals adjust to the light. I experienced some montis bleached after being exposed to the full power of leds and I needed to move them away from the top of the LR, but when I dimmed thee light they were OK on top
-second and IMO strongest advantage is that you can control the temperature of the light by simply dimming the blues and whites to your needs. Thats a good reason to have a dimming circuit
-third of all, sometimes you need to dim the leds a little bit so they don't run too hot. I found out that if I dim my white leds just a slightly little bit (I guess form 1000mA to 900mA) the heatsink temperature goes from warm to touch to completely cold
-other than that, if you have or will be planning to get a controller like Apex you would be able to create interesting effects like sunset or so

If your 50g has a center brace I would not use lens on the leds that are right above it or do two fixtures. That's what I did, I have a 36" tank and I'm using two 24 leds fixtures. Hope that helps

Ah so you are running 48 LEDs over your tank. I just assumed that 36 would be enough LEDs for any kind of corals. How is your tank doing with 48?

Thanks for your response! definitely helped me figure out what dimmable could be good for

 

[smoq]

Yeah, I guess 36 will be sufficient, I am running 48leds just because I upgraded form Solana which I lighted with 24 leds and I wanted to make the exact same fixture in case I would upgrade to 75g someday:sgrin:

 

[richardhmc]

Yeah, I guess 36 will be sufficient, I am running 48leds just because I upgraded form Solana which I lighted with 24 leds and I wanted to make the exact same fixture in case I would upgrade to 75g someday:sgrin:

Hmm 36 or 48 that's the question haha. I'd like to try SPS dominated tank.

 

[richardhmc]

Regarding BLUE to WHITE ratio. Should the amount of blues to whites be 1:1?

I'm leaning towards purchasing from reefledlights.com. They have the lowest price so far for 48 LEDs.

They offer dimmable and manually dimmable drivers. What is the difference?

 

[xxnonamexx]

what about a FOWLR tank?

 

[richardhmc]

what about a FOWLR tank?

What?

 

[scapone]

reefledlights are good i used them to build my first fixture. go with the dimmable drive with the d on the end its easier to work with. All youll need is a 0-10 enercell adjustble power source to fire it up

 

[richardhmc]

reefledlights are good i used them to build my first fixture. go with the dimmable drive with the d on the end its easier to work with. All youll need is a 0-10 enercell adjustble power source to fire it up

Thanks for your reply. I see that the d at the end is the difference between dimmable, and manually dimmable. What is the difference? Aren't both supposed to be dimmed manually?

 

[scapone]

yes but the one with the p you would have to make a seperate circuit to make it work i beleive, it would not work with just wiring in a qadjustbale enercell or similar type converter

 

[qy7400]

The letter at the end describes the dimming feature, D using a 1V to 10V and the P using the digital PWM reference. The D is most popular due to fact the Apex and RK controllers have a 10V output or using the wall-wart and pot where the P version is popular with the DIY Arduino controller, although I've used the P on my Apex and seems to work fine.

 

[smoq]

Yeah, go with a D version on meanwell, the "P" requires a PWM dimmer circuit, something like this http://cgi.ebay.com/LED-lighting-di...tem&pt=LH_DefaultDomain_0&hash=item2ead4b97d7 The "D" version is manually dimmable by simply using a pot wired into the meanwell. I'm gonna start writing a led build thread ver 2.0 in a minute, wait for it later today

 

[smoq]

just posted, hope that helps http://www.manhattanreefs.com/forum/diy-do-yourself/81156-cree-led-light-write-up.html

 

[richardhmc]

My tank is 18 inches deep. I want to keep mostly SPS, but at the same time, I want to cover the entire tank with light, instead of a more focused area of light. I hear that with LEDs, there are many dark spots. With 36 LEDs, is it sufficient enough, over an 18 inch deep tank, to grow sps?

Should I have lenses on my LEDs? If so, what degree would be sufficient?

 

[qy7400]

18" I'd go with either 70 or 80, the 80 will give you greater PAR at the edges where the 70 drops off a little for greater PAT directly beneath.

If you're handy soldering the Arduino based controllers are pretty easy to build, the Typhon controller build on RC cost me about $60 and now I have a 4 channel controller for sunrise/sunset, cloud cover or whatever I decide to program. This is it with the display off.

 

[smoq]

18" I'd go with either 70 or 80, the 80 will give you greater PAR at the edges where the 70 drops off a little for greater PAT directly beneath.

If you're handy soldering the Arduino based controllers are pretty easy to build, the Typhon controller build on RC cost me about $60 and now I have a 4 channel controller for sunrise/sunset, cloud cover or whatever I decide to program. This is it with the display off.

Could you explain more about that build, I'm very interested but at thesame time arduino-challenged. Thanks

 

[qy7400]

A little new to the Arduino myself but picked up pretty quick. The build is from this thread on RC, http://reefcentral.com/forums/showthread.php?t=1847680, basically the Arduino has built in PWM control (but only 5V) so the board has a circuit to switch the 5V to 10V, a clock chip for timers and the 4 buttons to change the program. While not required there is a 16x2 character display (think RK lite or AC Jr) that you can program to display the time, channel power or anything else you want to add.

 

[richardhmc]

18" I'd go with either 70 or 80, the 80 will give you greater PAR at the edges where the 70 drops off a little for greater PAT directly beneath.

So with 70 or 80 degree lenses, should I have 36 LEDs or 48 LEDs for the greatest growth in SPS?

 

[qy7400]

I'm just finishing a 40B for my office, same size just 2 inches shorter with 36 LEDs; no water yet but seems plenty bright for whatever I decide to put it.