DIY LEDs - The write-up

[der_wille_zur_macht]

wmilas,

It might be simpler than you're thinking. You could do a "traditional" approach with a big heatsink and LEDs spaced evenly across it. Then, plan which LEDs are on which drivers and have which optics carefully enough that you get the effect you want. For instance, if you have that one island with SPS on it, use an 1000mA or 700mA driver for the LEDs above that, and 40 degree optics. Then, on the rest of the tank, use 350mA or 500mA and no optics (except maybe 60's around the perimeter).

Just a thought. . .

 

[bobbyrocco]

Yes the wall is foam with agronite sand glued to it.

I used thermal tape to hold my LED's on the heatsink and so far so good. It was a lot easier than drilling and tapping 280 holes. Will see how it holds up long term!

Yes you can gang up multiple drivers on one ALC I have 6 drivers on each port of the ALC.

 

[HerdofCrickets]

Wow! What a great thread.

I'm thinking this is going to be my winter project - an LED light for my 180gal.

I'll start with making one for my 30gal frag tank, and if that goes off well then I'll give it a try for the big tank.

The price tag is scaring me a bit, but basically not buying bulbs or anything for 3-4 years would make it worth it.

180 gal tank = roughly 200 bulbs (100 white and 100 blue)

ouch.

haha

 

[der_wille_zur_macht]

Depending on which LEDs, drivers, and heatsinks you use, you should expect total cost to be somewhere around $7 - $10 per LED for large rigs (by my plans, I have yet to build that big - but will be over the winter, too.)

 

[HerdofCrickets]

Well actually, Soundwave did 48 LED's on a 4' tank w/ SPS, so I could do 100 on a 6' and still have good light...

 

[Skeptic_07]

If i was to make a light fixture for my 75 using 96 3w LED's and wanted to power them completely from solar panels.. would i still need drivers? would I end up with a completely natural dusk-dawn? what specs should i look for in solar panels?

 

[der_wille_zur_macht]

Well actually, Soundwave did 48 LED's on a 4' tank w/ SPS, so I could do 100 on a 6' and still have good light...

Depends on what you mean by good light - your tank is wider and deeper than his, for one thing.

If i was to make a light fixture for my 75 using 96 3w LED's and wanted to power them completely from solar panels.. would i still need drivers? would I end up with a completely natural dusk-dawn? what specs should i look for in solar panels?

You'd still need drivers of some sort, at least as a failsafe to keep current from going too high. I don't know enough about the output of solar panels to answer any better (for instance, if a panel is rated at 24v, what does the output actually look like? Is it regulated to 24v, or will it just be something close to that?)

 

[Skeptic_07]

i've no clue. I must ask my EE friend.

 

[der_wille_zur_macht]

Regardless, the circuits required to regulate DC in order to drive LEDs aren't that complicated.

Regarding using the output to simulate dawn/dusk - IMHO that would be a pretty risky approach. If you had clouds for a week, your tank would be in a rut. It is a really cool concept though, and you might be able to get a similar result without the risk. You could use the solar array and some sort of power regulation or storage (batteries?) to drive the LED array. Then, use a photosensor to take readings of sun intensity, and dim the drivers to match that value. Then, you could have programming on your controller to set minimum and maximum limits, and to deal with cloud cover, etc.

 

[Skeptic_07]

hmmn.. i see your point. I already have a couple computer power supplies, which is what i was originally going to use. Originally i was going to use the ALC module for reefkeeper to control the drivers. Maybe I could just buy panels with outputs that match the output of the power supplies i was originally going to use. I could put a couple switches between the power supplies and the drivers allowing me to switch from the panels to the power supplies during times of bad weather.

 

[der_wille_zur_macht]

I think you'd want it all automated - switching power sources, etc. I'm sure there are load balancing switches out there to flip between DC power sources. And I doubt that the panels are going to be a very stable source without some sort of "tank" attached to the system, but again I'm far from being an expert at solar power. I you used an array of batteries (like most solar power systems seem to), you could use the DC power supplies to charge the batteries when the solar panel output dropped below a set amount.

What's your goal in doing solar power? (I'm asking purely out of curiosity). I'm not sure I see the payoff in this application, since panels big enough to provide 400 - 500w for 8 or 10 hours a day are going to cost a few grand, I bet. The ROI compared to buying power is probably going to be at least 10 years.

 

[Skeptic_07]

yeah, i'm looking over the prices of those now and they're higher than I expected. My interest was pretty much because it would be a cooler way to mimic nature than using the ALC to control the LEDs. O well. scrap this idea. way too expensive.

 

[der_wille_zur_macht]

You could get the same effect by using a photosensor to control the drivers. Or, just write code that ramps up and down according to your taste. Once you have a programmable controller, the sky is really the limit.

 

[HerdofCrickets]

anyone have a good link to a DIY 36" fixture?

If not I'll probably end up taking the very first post on this thread and "shrinking" it down.

This is going to be an awesome winter project...

 

[terahz]

Hi all,

What a great thread (and long). I'm still at page 20 of part 2 and I've decided to light my 10G AGA using LEDs.

I'm planning to get:
6x Cree Neutral White XR-E
6x Cree Royal Blue XR-E
2x 700mA BuckPuck
1x 24DCV @ 1.7A 40W switching PSU (237-1299-ND from digikey)
And a heatsink.

I will control the lights with an arduino controller most likely.

Please do tell me if something in my list is wrong (# of LEDs, PSU, Driver ... anything). I will be ordering parts tomorrow (or later today, rather).

Thanks.

 

[kcress]

Your list looks OK except for the PS.

I'd go larger. The closer you get to the rating the hotter it gets and the less temperature head room you have with it.

I also don't like the one you have as it will be damaged on a sustained overload. Most will not.

Check out this one:
http://www.powersupplydirect.com/Product.aspx?ProductID=30477


I don't like open supplies around aquariums at all really. You are asking for trouble.

I'd reach for a desk wart myself. These provide some semblance of splash survival for both the supply and yourself.
Digikey T1049-P5RP

 

[terahz]

Thanks kcress, I will get desk wart you recommended.

 

[Skeptic_07]

You could get the same effect by using a photosensor to control the drivers. Or, just write code that ramps up and down according to your taste. Once you have a programmable controller, the sky is really the limit.

thats a good idea. Here's another idea I had: using an anemometer (wind measure device) to control the speed of powerheads! :lolspin:

 

[der_wille_zur_macht]

The problem we'd run in to with these simulation methods is that, unless you're living in the tropics, your environment is probably way different than a natural reef.

Hence, instead of using sensors to drive my lights and powerheads, I'm just writing code that'll simulate sunlight and weather in the tropics. The problem is finding reliable data on storm frequency, duration, and intensity.

 

[HerdofCrickets]

So... tell me if this process is wrong...

mount the LED's w/ epoxy and screws to a thin piece of stainless steel

wire it up

attach it to a heatsink

put on a fan

ka-plow - done.

obviously over-simplified, but the basic steps... yes?