Ultimate LED guide

[evilc66]

Never quite liked the icy blue look of some tanks I've seen.Thought maybe I could get more color variation

with the rgb tri.Wouldn't the mix bring about other colors like yellows for instance since the rgb forms white

light?I do know that reds will get filtered out at certain depths , but my tank is shallow and I recall while searching the web that green plants ( caulerpa? ) could benifit from it.I like the fact that the rebel stars are three LEDs in one which to me will be good for color blending.Reading the LED guide has proven very useful

though I am still confused about power requirements and whatnot.I want to do more of a warmer tone to a

DIY LED fixture , like how natural sun light has that yellow look to it.Found that I could solder my own rebel

and thought about a cool white , warm white and royal blue blend.The warm white could bring out the reds

and yellows and maybe help the green plants to grow without overpowering with reds and useless greens

in the rgb tri.Want to get this right before I take the plunge $$$

 

We don't work with depths that light gets effectively filtered out. The warmth of the color can easilly be changed by adjusting the balance of white and blue LEDs. Fine adjustment can be done with an adjustable driver.

 

I agree that the tri-Rebels provide great color blending (I use them on one tank), but using other colors really provides no great benefit to the corals. Heavier amounts of red can help with the growth of macros, but it can also cause problems with corals. The amount of red in a cool white LED typically is plenty to grow most macros pretty well.

[jiriki76]

I could be wrong about this, I've heard adding a few red LED's will add pop to the more reddish corals such as acans. Obviously, it would only be for aesthetic reasons but sacrificing 1 or 2 LED's for a red one every 2 feet might not be a bad idea if the tank has a lot of red corals.

[evilc66]

If you need more red, you could substitute in neutral white LEDs. It raises the red output without sacrificing the blue much. Honestly, I have no issues with red colored corals, including a few acan polyps I have at the bottom of my 4g LED tank.

[Jammaroo]

Added this to show what we're looking at as far as color temperature.The warm whites maybe too red after

all and I may go with some neutral whites instead as Evil suggested to me.I'll have to research it more , the

warm whites are more aesthetically pleasing to the eye though.

Edited March 4, 2009 by Jammaroo

[evilc66]

Keep in mind that that graph represents the ideal black body color temp plot. There are many ways to get to a certain color temp (which is painfully obvious in MH bulbs). Most LEDs that you find are not the ideal versions, and you have to pick the appropriate tint bin, which is very difficult sometimes.

 

What are you basing the comment thatwarm whites are more pleasing to the eye on? In the home, it's what we have been conditioned to deem pleasing to the eye, and unfortunately the CRI (Color Rendering Index)usually follows that trend. What we need to think of here is how to appropriately simulate the conditions that our corals would see, which is typically heavy in blue.

[Jammaroo]

What are you basing the comment that warm whites are more pleasing to the eye on?

 

What we need to think of here is how to appropriately simulate the conditions that our corals would see, which is typically heavy in blue.

Personal taste really for the warm whites.I am drawn to more warm than cool colors , nothing scientific.

True we must try to recreate the corals natural light conditions.My approach is to make a DIY LED fixture

that is pleasing to me without overly sacrificing the corals needs.

[evilc66]

My only concern going to warm whites is the potential for pest algae issues.

[reef55]

Ok, how about a bigger design then...

 

48" long, 24" wide, 24" deep tank.

 

40 degree reflectors obviously, I'm thinking 2 to 1 white to blue ratio, with a total of 96 xr-e's.

 

My biggest problem though is power supply design... that's an awful lot of expensive buckpacks

 

Help

[phaze5]

Hey with a small voltage power supply does that mean you have to run at higher amp draw or can you just not run as many leds. I going with the last one...

meaning instead of 6 at 24vdc-you can only run 4 at 12vdc per buckpuck?

Edited March 5, 2009 by phaze5

[evilc66]

Ok, how about a bigger design then...

 

48" long, 24" wide, 24" deep tank.

 

40 degree reflectors obviously, I'm thinking 2 to 1 white to blue ratio, with a total of 96 xr-e's.

 

My biggest problem though is power supply design... that's an awful lot of expensive buckpacks

 

Help

 

Might be a little light on LEDs. It would require spacing that could cause spotlighting. Moreso front to back. With 96 LEDs, you are looking at 4 rows of 24. For a 24" wide tank, I think going up to 6 rows would give you better results. Adding a few more tot he rows would get you closer to a 1.5" spacing that will work better for 40 degree optics.

 

Powering it is always going to be expensive. The Meanwell ELN drivers are your best choice right now for running lots of LEDs. The ELN-60-48 will allow you to run 26 LEDs (2x13) at 750mA, and 13 LEDs at 1A. Getting the dimmable version is a little pricey right now.

 

 

Hey with a small voltage power supply does that mean you have to run at higher amp draw or can you just not run as many leds. I going with the last one...

meaning instead of 6 at 24vdc-you can only run 4 at 12vdc per buckpuck?

 

What you can do is run smaller strings at a lower voltage, but run multiple strings in parallel. The driver has to support a higher current to get the most out of the LED though. For example, if you want to run 6 LEDs at 1A, you either have a driver running 1A at 24v and run all six in series, or you have a driver running 2A at 12v and run 2 3 LED strings in parallel. Works out the same, but it's harder to find drivers with higher currents. The Meanwell drivers are probably the best for this.

[pbenner]

Any thoughts on the number of LEDs for a 2.5gallon? Thinking about putting a reef on my desk at work...

 

lol!

 

Paul

[evilc66]

Ideally, 10. Thats what I use in the single Satellite retro that fits perfectly over the 2.5g tanks. You can go less than that, but the coverage suffers a bit.

[pbenner]

So like this:

 

X X X X

X X X

X X X X

 

?

 

2.5" spacing from corner to corner across and from edge to edge on the diagonals?

 

Best,

 

Paul

[evilc66]

Well, thats more like 13, but who's counting

 

You can do that, but it's not necessary. A simple 5x2 worked out perfectly for me.

[chazde3]

Well, thats more like 13, but who's counting

 

You can do that, but it's not necessary. A simple 5x2 worked out perfectly for me.

More like 11 but who's counting.

 

You could go

x x x

x x x x

x x x

 

But a 5x2 would work better with the size of a 2.5g tank.

Edited March 5, 2009 by chazde3

[evilc66]

Pfft. 11, 13, I'm sick and I say it's the same

 

I don't see much need for three rows on that narrow of a tank. Doesn't mean you can't do it though.

[pbenner]

I assume that "lm" is lumens? More lumens = better for corals on white lamps?

 

Thanks,

 

Paul

[evilc66]

When talking stricly about LEDs, yes. A higher lumen white will provide higher PAR numbers. You can't use lumens as a comparison to other light sources though.

[merk1_99]

On my 4 gallon I am going to do 2 x 6...

[evilc66]

What type of 4g tank?

[ls7corvete]

do you have guidelines for spacing with different degree optics and depths?

ie

40 degree at 12" at 24"

60 degree at 12" at 24"

 

Maybe we can put together a chart?

 

Any updates on writting more info on the superflux and other leds, didnt you mention a new section for them?

[evilc66]

Spacing doesn't really change for the depth of the tank. You still have to light portions of the upper sections of the tank.

 

Typically, I have suggested ~15." spacing for the 40 degree optics, and 2-2.5" spacing for the 60 degree optics.

 

I haven't had a chance to work on the other LED section. I still need to finish the last portion of this guide.

[pbenner]

For the Rebels with 3 LED's on them, are the considered 3 seperate light sources for calculations, or are they just one LED? Also, do they make a 60 degree optic for Rebels that you know of?

 

How do you attach the back of the LED PCBs to the heatsink? I assume that you drill/tap a hole and then screw them on through their mounting block?

 

Do you know of a cheap place to get a custom heatsink made for mounting LEDs to? How does the Optic stay attached?

 

Also, if using the 3 LED rebels, should I mix colors on each lamp? Do like 2 white and 1 blue and 2 blue and 1 white alternating to get a better blend of color for the tank?

 

I'm a pretty good hand at soldering, and I think this is something I can do.

 

Thanks,

 

Paul

[evilc66]

For the Rebels with 3 LED's on them, are the considered 3 seperate light sources for calculations, or are they just one LED? Also, do they make a 60 degree optic for Rebels that you know of?

 

Not sure what you mean here. Calculations for what?

 

They only make a 25 degree lens for the triple Rebels. While this setup has some nice advantages, it gets expensive really fast, and is really only good for super high light setups.

 

How do you attach the back of the LED PCBs to the heatsink? I assume that you drill/tap a hole and then screw them on through their mounting block?

 

Drill and tap is the prefered way. Gives maximum contact area and pressure for thermal transfer. Thermal expoxy is an option, but can lead to higher die temperatures.

 

Do you know of a cheap place to get a custom heatsink made for mounting LEDs to? How does the Optic stay attached?

 

Chris at Nanotunners can do truely custom heatsinks, but you would have to model it yourself to keep costs down (not Sketchup, a real CAD program that can export to IGES, STEP, or STL). If you want just a big heatsink, HeatsinkUSA is a good source for big cheap heatsinks.

 

Also, if using the 3 LED rebels, should I mix colors on each lamp? Do like 2 white and 1 blue and 2 blue and 1 white alternating to get a better blend of color for the tank?

 

You can mix up the colors any way you want. It will offer the best color blending by far.

 

I'm a pretty good hand at soldering, and I think this is something I can do.

 

Thanks,

 

Paul

 

Soldering wires and through hole components is very different than surface mount. Can't use a soldering iron in the typical sense here. Hot air, or a reflow setup is needed here. There are some simple ways to get this done on the cheap at home. Either way, Rebels are not an easy LED to work with.

[reef55]

Might be a little light on LEDs. It would require spacing that could cause spotlighting. Moreso front to back. With 96 LEDs, you are looking at 4 rows of 24. For a 24" wide tank, I think going up to 6 rows would give you better results. Adding a few more tot he rows would get you closer to a 1.5" spacing that will work better for 40 degree optics.

 

Powering it is always going to be expensive. The Meanwell ELN drivers are your best choice right now for running lots of LEDs. The ELN-60-48 will allow you to run 26 LEDs (2x13) at 750mA, and 13 LEDs at 1A. Getting the dimmable version is a little pricey right now.

 

So the opening above my tank will accomodate an 18" wide by 40" long grid of LED's. If I did 6 rows of 20, you think that would work well with the 40 degree optics? Speaking of the optics, closest I found were the Carloc 20mm wide ripple lens to 40 degrees: http://www.ledsupply.com/10211.php

 

Am I missing an optic out there?

 

For power supply, this gentleman out of germany has diy kits with linear regulators for under $3 each, and each can power 6 LED's on 24VDC input. So thinking of getting 20 of those kits, and powering them off multiple 24VDC power supplies: http://www.mpja.com/prodinfo.asp?number=16854+PS

 

Good idea / bad? Thanks again for all your help