I know this is Nano-Reef.com but..., LED Lighting questions for future build Options

[evilc66]

I really like the look of natural sunlight over a reef... But I think I might be missing something here. Natural sunlight (as perceived by the human eye) is going to have a slightly yellowish color to it. If you add strong blue light, yellow + blue = green, right? Of course I could be way off... but that's just what came to mind.

Either way, I would think that fluorescent tubes would be needed to overcome the brightness of the sunlight (since LED's have relatively low lumen output).

Nah. Doesn't quite work out that way. Adding blue light to sunlight just makes the tank bluer. LEDs are certainly capable of adding every bit as much color as fluorescent tubes. Not quite as cost effective though

[Kamy]

Nah. Doesn't quite work out that way. Adding blue light to sunlight just makes the tank bluer. LEDs are certainly capable of adding every bit as much color as fluorescent tubes. Not quite as cost effective though

No definitely not quite as cost effective for the initial layout, but maybe over time considering electricity usage, lamp replacement costs, and soon "Cap & Tax".

[ajmckay]

Nah. Doesn't quite work out that way. Adding blue light to sunlight just makes the tank bluer. LEDs are certainly capable of adding every bit as much color as fluorescent tubes. Not quite as cost effective though

There's definitely a "coolness factor" to be had as well...

As for cap & tax... well, it can kiss my shiny, soon-to-be halide ass... If that happens I'll never be able to afford LED's.

Kamy, I just realized that this post is from February... Wow... make sure you post pics sometime.

[Kamy]

There's definitely a "coolness factor" to be had as well...

As for cap & tax... well, it can kiss my shiny, soon-to-be halide ass... If that happens I'll never be able to afford LED's.

Kamy, I just realized that this post is from February... Wow... make sure you post pics sometime.

Oh I will as soon as the tank buiild begins This is going in my new entertainment room, (read man cave), which is just now in the process of being built. That entailed building a separate detached garage to move all of my stuff over, then closing off the existing attached garage.

Drywall is going up next week, flooring a week or so later, still have to finish the plumbing and get the HVAC installed too. Long process, but it is coming together!

[jewbilee]

I read through the threads posted in the previous page and I love the idea... Were I to have my own place this is definitely something I would consider for a larger tank, especially if it were to go on a fresh setup. Not having to buy the MH's, ballasts, and all that other stuff would definitely help offset the cost of installing the tubes!

Good luck with the build and definitely keep us updated. Should be awesome.

[Kamy]

Evil, I was rebrowsing hobogato's tank here again

http://www.reefcentral.com/forums/showthre...hreadid=1457056

He is running 580 watts of actinics to reach that level of blueness in his tank. Any rough idea of how many LEDs to reach that comparatively?

This post has been edited by Kamy: Nov 6 2009, 10:43 AM

[evilc66]

Wow. Thats a lot of actinic. Unfortunately you are treading in new territory here. Needless to say, you are going to need lots of LEDs, and certainly optics to get the effect you want. You shouldn't need tight angle optics, but something like an 80 or 60 degree lens will really help get the color deeper. Try this: lay out a grid over the entire top of the tank with 4" spacing on the grid lines, and the grid about 6" away from all tank edges. Where each grid line intersects, that's where a blue LED will sit, but with the areas for the solar tubes removed. That should get you somewhat close.

[Kamy]

Wow. Thats a lot of actinic. Unfortunately you are treading in new territory here. Needless to say, you are going to need lots of LEDs, and certainly optics to get the effect you want. You shouldn't need tight angle optics, but something like an 80 or 60 degree lens will really help get the color deeper. Try this: lay out a grid over the entire top of the tank with 4" spacing on the grid lines, and the grid about 6" away from all tank edges. Where each grid line intersects, that's where a blue LED will sit, but with the areas for the solar tubes removed. That should get you somewhat close.

That's going to have to wait until I get home Should be interesting to draw out, I'm guessing some sort of lattice arrangement that the LED's will be mounted to. Hopefully I'll have time to start drawing it out tonight. Thanks for the conceptualization

[evilc66]

What you may be able to do with that is use aluminum L-channel to make the grid. If you build it right, and bolt all the parts nice and tight, the whole grid will become your heatsink.

[Kamy]

What you may be able to do with that is use aluminum L-channel to make the grid. If you build it right, and bolt all the parts nice and tight, the whole grid will become your heatsink.

Right, and if I extend either the long or wide axis (or both) out to the edge of the hood, easily suspended above the tank too

[evilc66]

Yes indeed. With some careful planning, it could be quite the setup.

[Kamy]

Okay, question for those who know. All input is welcome.

21" Solatubes come with 2 different types of domes, the first dome captures more light earlier and then later in the day by use of a fresnel type lens, and then blocks some of the strongest daylight during the noon day sun.

The second type of dome just has no Fresnel lens and allows the strongest part of the day sun to pour down the tube.

Here is a chart of what I am talking about.



Question is, what is the consensus of which dome lens to go with? I think I would lean toward the one with the Fresnel lens, as I would pull more usable light for longer periods. (It is seasonal here, this winter solstice I will have 9h:37m of light here, thank you wolframalpha.com)

What do folks here think would be better for overall coral growth? More usable light for longer periods, or more powerful light but at shorter periods.

For those solar physicists out there, I'm at 37, 44 N

[evilc66]

Hmm. I would say use the fresnel. Mainly because of the more even lighting during the day, but also for the limiting factor at high noon. During the summer, that could be an awful lot of light.

[Kamy]

Update,

After discussing with JD over at RC, he also has a 30" wide tank and the 14" tubes are throwing enough light for him and that works out for me, because that leaves me room for supplemental actinic lighting. The 21" tubes would have been too large and likely thrown too much sunlight for me to overcome with LED lighting and squeezing any other lighting in there would be a tight squeeze also.

Tank placement will depend on where I can route the tubes through the roof trusses. If I butt the two outer tubes against the trusses (outside edges of trusses are just about 26") and center the center tube between the trusses, that gives me plenty of room all around for LEDs

I could also go with T5's or PC's, but where is the fun in that? Also, I'm hoping to come in under the cost of running PC's or T5 electricity and replacement cost wise.

Here are a couple of screen grabs I did in sketchup to explain what I am talking about.

First, here is how the tubes would align against the trusses



The 14" tubes give me 8" in front and behind the tubes, 9" from the side of the tank to the two outer tubes and then 6" between the center tubes and the outer tubes.

So this is a frame concept I came up with.



If I could get away with just single strings of LEDs mounted to the aluminum L channel, great! But I have been thinking, I might want to add some white LEDs into the mix, as I work all day, I am not sure I just want to see my tank lit straight up blue for a short while in the evening when I get home, a few white in the mix might help that, I'm guessing opposite of what everyone is using for standard lighting i.e. 1 white for every 2 RB. that would likely then require staggering the LEDs, so I added heat sinks along the frame. I could easily fit a 12" by 4" heatsink along each portion of the frame (doesn't need to be that big, just an example of what would fit)



So, while drawing this out, I am realizing that this is a seriously ambitious project. And of course, I have to design it in such a way I could easily move/remove it and not interfere with the tubes. Also I don't want a ton of light spilling out of the tank top, so I want to control light seepage from the hood.


Okay, so, how about a guesstimate on how many LED's to knock down the yellow of sunlight? And could I throw 1/3 whites in there and still realize some blueing of the sunlight? (I could put the whites on a separate power supply, that way they wouldn't add to the sunlight)

[Kamy]

This is a whole lot of LEDs 68 total



Certainly looks like it would throw a whole lot of light.

LED's are spaced out on a 4" grid starting approximately 6" inside the tank edge. Gets a little tight around the area of the tubes, so If I do go this way, I'll have to pay attention to fit/measuring in the vicinty of the tubes.

Wiring up something like this looks like it would be a #####. From what I am reading, most are using or going to use the Meanwell ELN-30-24 and are driving 12 LEDs. I would need 6 of those to drive this amount of LEDs.

Could I use the ELN-60-24 and then only need 3 drivers? (I know the amount of LEDs do not divide equally, would I need to squeeze an extra 4 LEDs in somewhere, or somehow or other draw the extra current off?) As I understand it, as we are wiring in series, and these are constant current drivers, so even if a string was short a few LEDs it should operate correctly, yes?

Also, the Meanwell drivers run on line power, so I can plug it right into the wall, well, does each driver need it's own plug or can they be wired together into one plug?

And I'd like to hook this to an ALC, so I am anxiously waiting the arrival of Evil's ALC and see how that works out

[evilc66]

You can use the ELN-60-24D, but you will need 4 (3 strings of 6 LEDs on 3 drivers and 3 strings of 3 on the fourth, making 63 LEDs), and each LED will run at a lower current (830mA vs. 1000mA) That probably won't make much of a difference though. When wiring in parallel like this, each string on a driver has to have the same number of LEDs.

They can all be wired to the same cord if you like. Nothing stopping you there.