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Discussion Starter · #1 ·
I'm going to be building a LED light for an upcoming tank build - a 24 inch cube tank from Protean. The plan is to purchase a 10" by 20" heatsink from Heatsink USA, and then mount 10 EndorStar 3-Up leds to it. This will give 30 emitters for the tank - which should be more than enough. I'm planning on getting 5 each of the "Cool white" and the "Neutral" EndorStars, to simulate a daytime light color. The cool white emitters run about 6000K - 10000K, while the neutral white emitters are more in the 4000K to 6000K range. I plan on placing the emitters in an alternating pattern on the heatsink so that they mix well.

These emitters can be ran up to 1000mA, but I'm going to be using the 700mA BuckPucks - one driver per every 2 stars since they can drive up to 6 of these emitters. I'll be using dimmable drivers so that each group of 2 emitters can be dimmed independently of each other.

I'm also going to get one optic to see if it's something I'd like to use on all of them. They help to focus the light since the emitters alone have a wide throw. We'll see.. photos of course!

Cool white - Cool-White 3-Up EndorStar - LED Supply.com
Neutral white - Neutral-White 3-Up EndorStar - LED Supply.com
BuckPuck - 3023-D-E-700P Wired BuckPuck - LED Supply.com
Optic - EndorStar Optic - LED Supply.com

Heatsink - 10.000 inch profile custom cut aluminum heatsink (10" x 20")

Does anyone see any pitfalls with this? Each Luxeon Rebel throws about 3W of light, so this fixture will have about 90W of LED light. This should be comparable around a 175W - 250W metal halide (I think?) - which seems like more than enough light even dimmed back a bit ("sun shafts" or whatever you want to think of it as).

The tank will be holding either a group of R. imitator 'Varadero' or a group of R. fantastica - the target is sometime in the spring or early summer. Plants will be mostly miniature orchids and a showy center piece bromeliad clump of some kind. The tank itself won't even be ready for planting till February give or take a few weeks - so this thread will transition into that one at that time.

I'd love any input that anyone could give me. Of course I'll take photos and document the process of building this light. My estimated cost of materials is about $300.
 

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Discussion Starter · #2 ·
So, I went ahead and did this over some time with my father a couple weeks ago. He's much better with a soldering iron than I am - so it worked out for the best.

In case anyone else wanted to follow along and build a similar unit - I'll post a step-by-step for you.

The only thing that I used, other than standard aluminium parts, was a tube of Locktite Hysol Thermal Adhesive that I bought from McMaster-Carr:

Hysol US1750 Electrical Urethane System

I'd recommend buying the applicator gun with it.. though I just eyeballed the 1:1 ratio and mixed it with a toothpick and all seemed to work. This stuff dried pretty slowly - it didn't appear to be drying at all for several hours - but by the next day it was hard as nails and perfectly clear.

First, you'll need a heatsink. I have a 24"x24"x24" cube that I'm lighting, so I bought a 10"x20" aluminium heatsink from heatsink USA to spread the LEDs out on:




When you get your heatsink and you're ready to start gluing things to it, you'll want to clean it off really well with some rubbing alcohol. This will remove any coatings that might be on it from the factory. It'll make sure that your LEDs won't fall off because of a bad glue job.


Here's the guts of the system. 5 Buckpuck drivers (one not pictured) and 10 3-up Endorstar LED units. Each Endorstar has 3 Luxeon Rebel emitters on it, giving this build a total of 30 emitters.

To avoid having too white of a light I purchased 5 "cool white" and 5 "neutral white" endorstars. I wired them cool - neutral - cool - neutral so that the light would mix well.







Each emitter is rated to put out 70% of it's original brightness after 50,000 hours of use. Thats 2,083 days of use, or 5.7 years of burn time. At only on 12 hours a day, they'll last over 11 years before they dim to 70% output. The total power draw for this system is only 90 watts.

LEDs are becoming very popular in reef tanks - this light is sort of a test run for a bigger build I may do in a couple years for my 150g reef. We'll see how these last!

One important consideration that you'll want to make is how you're going to attach the LEDs to the heatsink. You'll want to choose something that is both thermally conductive and electrically resistant so that you don't need to worry about charging up your heatsink. Each Endorstar is supposed to be non-conductive out it's base, but better safe than sorry! I chose Hysol urethane which can be had for about $15.00 from McMaster-Carr. One tube will last you through several builds!







When you do glue the LEDs down, make sure that the solder pads are facing towards each other so that your solder job will be easier. In this case, we can only power 2 stars per driver, so we're just going to solder straight across the middle to connect up each set of 6 emitters.

This adhesive dried solid overnight - I'd give your job at least 24 hours to dry before trying to solder the LEDs. At first I was worried that it wasn't going to dry... nothing seemed to be happening after a few hours. The next day however everything was nice and solid - rock hard in fact. I also like that this stuff dries clear - it doesn't dry silver like the Arctic Silver epoxy that most people use. The Hysol adhesive is also significantly cheaper than the Arctic Silver when you consider how much of the stuff you get for $15.00.

Once everything has hardened up, it's time to start the soldering. This is where my father took over - these solder pads are TINY and VERY close together. Don't drink too much coffee and then try to do this!


Another thing to note is that LEDs in general are lead free. So those pads are actually tin - which melts at a much higher temperature than lead. If you have a really cheap soldering iron you might not be able to heat the tin enough without damaging the plastic emitters. Be careful and work as quick as you can to avoid overheating the emitters. Also, keep in mind that you have a huge heatsink working against your soldering iron - it was quite hard to solder these at first even for an electrical engineer! We ended up using a good bit of flux with lead solder, but we first melted the tin pads and applied our wire, with a bit of extra lead overtop to seal the deal. You can also work with pre-tinned wire, but I didn't think of that in time...

Each cross wire goes from one + to the other -. Once you get both pads soldered, you'll want to make sure that you're not conductive between the two. The black wire and white wires there go off to the driver for these 12 LED emitters.




Once we got everything soldered onto the starboards, it was time to clean up our connections to that no extra flux was present on the heatsink. This was as simple as rubbing everything with some alcohol. It was also a good test of the connection strength.


You can also see part of the hood that this is going to be bolted into when it's all done there. It's basically an aluminium scaffold that supports the heatsink/LED array a couple inches above the top of the tank. It will be encased in wood to hide all the electronics.

Once everything was clean, I wanted to tidy up the wires a bit - cable ties to the rescue! It was quite a mess - lots and lots of wires going everywhere!




It was much more manageable after making a nice bundle of the wires. If you use the same Buckpucks that I used, or you build your own, you may have a dimmer set up to work on some of your LEDs. That's what we're mounting in this photo. At the back of my hood is a box with all the dimmers and drivers mounted in it. Each dimmer controls two endorstars.


And finally, of course.. it all works! You can see the different color LEDs pretty well in this photo. It's bright!




It also seems like the light spread is pretty good without needing any additional optics for the LEDs. We'll see once I have my tank if that works or not.
 

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I was going to test on reef tank . When they get the cost down . but you would only need half of them for plants . good idea . and look fun . allot more then paying 500 to 1000$$. for premaid fixture . love to see some plants under it . it well have less shadowing because light score is come from all over . more natural light . sweet good luck
 

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Discussion Starter · #4 ·
I went with the frog tank light first because my reef is 150g and I'd need to build something several times larger for that. It wasn't in my budget =p

I'm very excited to get this onto a tank as well - for now though, it's just in storage :(

I'm still waiting on the tank...
 

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I've never heard of a BuckPuck. I'll have to research them; they sound like they'd be helpful in my own lighting project. How did you send power to the BuckPucks? What's between the wall outlet and them?
 

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Nice project. And I am encouraged that Dad's can still help out and still are willing to do so...
 

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Discussion Starter · #8 ·
Wow, somehow my subscription for this must have dropped off. Sorry for the months of neglect!!!

The buckpuck is simply a little bit of electronics that takes the input DC power and switches it to a constant current 700mA 9V supply which is enough to power 6 emitters.

I forgot to link the power supply I used. It's a 24 volt 6.5 amp 150 watt supply that you plug into the wall. The output is attached to a wire from which all the buckpucks are driven. I got it at MPJA, which is a great place for random electronics. Here it is: 24V, 6.5A MEANWELLPOWER SUPPLY-MPJA, Inc.

My tank from a certain custom tank company should be about to ship any day now.. so then I just need to get my stand to me here in Las Vegas from Ohio (which will be fun, I'm sure) and then I can post a "all done" shot for you to check out. For now, this whole setup is sitting on a shelf in the closet :(
 

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Discussion Starter · #10 ·
This unit is "live" now over a 60 gallon cube in my living room. I found that with the LEDs full brightness the plants yellowed a bit, so I have them turned back maybe 10-15% right now and things are growing amazingly well.

I have several orchids in the tank that bloom, two that bloom non stop. Bromiliads grow well, moss grows well. No complaints from me! I'd do this again in a heartbeat.

For the life of me I couldn't figure out how to get image URLs off Google plus this morning, but I did upload several photos just now.

You can check them out in my album, https://plus.google.com/photos/110032837456034395696/albums/5686755055157330385

Let me know if that doesn't work.. or if there's a way to go from Google+ to posting the images directly on here. Who wants to go to an album?!? :mad:
 

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WOW @ That heatsink! Is that much passive cooling needed for that many LEDs? Could you get away with smaller heatsinks? Say 1 each for each endostar? Maybe something actively cooled, as in a computer heatsink?

Also, to solve that problem of having the huge heatsink working against you why not solder the connections before gluing to the heatsink?
 

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Discussion Starter · #13 ·
That tank is 24" from top to bottom, and the lights are 4 to 5 inches above the top of the tank. Factor in the dirty top glass, and I think you could still grow even the most light demanding plants at the bottom if you had them full brightness.

Heat is the number one thing that is going to reduce the life span of your LED emitters, hence the large heat sink. You certainly could do individual heat sinks, or smaller fan cooled heat sinks like in a computer, but here's why I didn't go that route:

- A single large heat sink means you only have to deal with mounting a single heat sink
- A large heat sink means that the whole setup can be completely silent. No fans!

After a day of running, the heat sink is noticeably warm to the touch. Not as hot as a car that's sat in the sun all day, but you can feel some warmth for sure.

I glued the LEDs to the heat sink first because that made it easier to know exactly how much wire I'd need to put the LEDs exactly where I wanted to have them. Also, these things are very, very, small.. each Endorstar is well under an inch across.. and having them totally stationary when you're soldering them makes it a heck of a lot easier to do.
 

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Thats some awsome light coming from that setup, figured it would be to bright.
Its good you can dim them :thumbs: I like the big heatsink in alot of ways :D
I find if you at least tin the pads of led before mounting to heatsink, will make life easier ;)
 

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Makes sense, although a soldering bench would really help to hold them stationary.

The reason I asked about the need for a large heatsink is that long term, for my rack, I want to do something like this, but I have verts, so I would like to have an individual heatsink and set of endostars per tank.

I was thinking 3 endostars for each 29 vert and 2 for each 20 vert. I don't nessesarily want a 36" long heatsink running the length of the rack.

Are there programable dimmers for these? I'd love to be able to slowly ramp them up to max brightness for a peak daylight and back down for dusk.
 

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Discussion Starter · #16 ·
I think a smaller heatsink would work just fine. Worst case, you could blow a fan down the rack over the tops of the tanks.

You can program them using an Arduino, if you wanted to get fancy. You just need to send a variable signal through the wires where the potentiometer would be attached to control how bright they'd be.

I'm sure you could have them fade in and out without much trouble. It's just varying the voltage you send back in.
 

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i wish the heatsinks were cheaper . i have been playing with the rebel and rebel star for the past year and love the out put they are capable of. i am happy to hear the light wave length is palatable to the plants. this is the #1 reason i havent started playing with it yet. anyway looks like i better start thinking about it. thanks for the review and id say with a year of watching plants under it you have good enough info for me.
 

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The reason people use article silver is becuase its liquid metal and therfore will transfer heat to the heatsink what you did is isolate the leds from the heatsink and the thermal conversion is going to be minimal and the output of your leds is not going to last as long.
 

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Discussion Starter · #19 ·
The epoxy I used it designed for working on heat transfer units in medical settings (cooling blood, etc). It can also be used for potting electronics, and is totally non conductive.

Here's the datasheet for the Hysol 1750 that I used. I'm sure arctic silver would be better, but the amount of adhesive between my emitters and the heat sink is negligible and so I am not worried about it.. and having the emitters all electrically insulated from each other was worth it to me since I have a spray tube running right below this fixture.

http://tds.loctite.com/tds5/docs/HYSOL US1750-EN.PDF
 
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