75 Gallon LED Hood

[phalanx]

So I'm not hijacking the other person's thread, here is the progress on the LED hood I'm currently building:

I'm in the process of building an array for another member on this forum with a 75g tank. I was going to start a thread soon detailing the entire process but here is the general idea. We are making a 100 led array with a 50/50 cool white and royal blue mix all of which are Luxeon Rebels. The general layout will look like this:

The heavier lines are the outline of the 2 heatsinks being used.

So far I have reflowed all the Rebels onto their stars:

And I just finished making a drill template for the holes to mount the stars to the heatsink. The 2 sinks are wrapped together with the large one on top:

This weekend I'm working on the prototype of the custom LED driver for the array. It will run directly off of 120VAC and will power up to 25 LEDs per channel. I'll be putting 2 channels on a single board so only 2 driver boards will be necessary for the entire 100 LED array. Once I have the prototype up and running, I will probably detail the design steps of making one in case other people are interested in the methodology.

 

[phalanx]

More updates. I got the first channel of 4 up and running. The empty space on the board is for the second channel. Channel 3 and 4 will sit on a second board.

Turned off (with a quarter for size reference):

Turned on (with 24 LEDs in series at 750mA):

 

[phalanx]

Managed to get the mouting holes drilled in the heat sinks. I was lucky enough to be able to use a machine at work. It was drilled with a stationary mill with a CNC table. Now I need to have them tapped. I'm also lucky enough to have access to a drill press with a tapping head at work.

 

[Bruno]

What do you think yhe total cost will be when your done? What are you going to use to house all of these lights?

 

[s_kelley]

Holey Moley thats alot of light, whats going to be the total par rateing?

 

[phalanx]

What do you think yhe total cost will be when your done? What are you going to use to house all of these lights?

The guy who is actually paying for all this will have to chime in with all the costs as well as the final mounting solution. Right now I can safely say that it is not cheap by any stretch of the imagination (over $500) but it is substantially cheaper than buying a pre-made solution and will outclass their performance by a large margin.

 

[phalanx]

Holey Moley thats alot of light, whats going to be the total par rateing?

Total PAR? I really don't have enough experience with these to say for certain. I'm hoping the person I'm making it for will borrow a PAR meter and let us know how it performs.

 

[phalanx]

The heat sinks are now tapped as well. I managed to tap them all in about 45 minutes. About 3/4 of the way through the tapping job, I snapped one off flush with the sink so I drilled 2 new holes for the star.

 

[DoctaQ]

im guessing that it was not a manual tap if you finished so quickly, the #4 is so small that sometimes it slips out of the wrench handle for me
nice work man, wanna hear something foolish?
im toying with the idea of converting my house lighting over to led, but thus far i dont want to do anything that is not easily reversible as in, im just playing with the sockets now.
man, i could never find phillips head #4 macheine screws.

 

[phalanx]

You're right. I have access to a drill press at work that has a tapping head. When the head encounters enough resistance, it clutches out so it doesn't break the tap. When you start pulling the tap out, the clutch reverses allowing it to come out. It saves tons of time and some how I still managed to snap a 4-40 bottoming tap.

The only thing crazy about LED illumination in the house is the cost. It's crossed my mind many times but it just gets too expensive when I start thinking about what I want to do.

 

[number1gsxxr]

The guy who is actually paying for all this will have to chime in with all the costs as well as the final mounting solution. Right now I can safely say that it is not cheap by any stretch of the imagination (over $500) but it is substantially cheaper than buying a pre-made solution and will outclass their performance by a large margin.

So far I've spent $216 on the heatsink with shipping, and $510 w/shipping on the LEDs and mounting stars. I still need to purchase the lenses which should be around $100 and build the hood to hang the heatsinks.

As far as PAR, hopefully I will be able to borrow the club PAR meter again and get some numbers once the LEDs are complete.

 

[number1gsxxr]

As far as the hood goes, I'd like to build something like the one in these pics. Instead of white I'd stain it to match my tank stand.

I have a family friend that does general carpentry work but his quality isn't the best when it comes to finish work. I'm open to any suggestions of people who can build a hood. I can provide the materials and pay for labor.

 

[MrReefer]

I was wondering if you could glue the stars to the heat sink or do you have to mount them? Interested in building my own but all that drilling looks intense.

 

[snowmaker]

Similar question - do you use any kind of heat conductive substance in between the LED and heatsink? Is there a heat conductive adhesive that would work?

 

[afboundguy]

You are supposed to use either a thermal glue or thermal paste... The glue works best but then it's a PITA to replace a blown LED. IMO the paste with the LED's screwed in would be best for ease of swap out. They also have thermal sticky pads but they're not as good at heat transfering and I've read some horror stories about them falling off...

 

[JayM]

is the thermal paste/glue reef safe? Are the LEDs going to be covered by anything protecting them from salt spray?

 

[DoctaQ]

thermal paste/glue should never get into the tank but id think its pretty toxic although if any gets in it will be a tiny tiny amount.

ive used thermal tape (pm me), two part epoxy, drilling and tapping and i can say that drilling and tapping is a major pain but is cheapest and most effective but it does give the risk of shorting the driver to the heatsink if you are slopping with the solder. ive never had the tape or epoxy pop off, the trick i guess is to clean the heatsink and star and apply strong pressure when the adhesive is attaching.

 

[number1gsxxr]

I forget if it was on here or Nano-Reef forum but I had asked about thermal interface material (TIM) and Bill (Phalanx) said it was unnecessary. I've always used it when assembling computers for the CPU heatsinks but I'm sure he'll chime in when he gets a chance. He travels a lot for work.

EDIT: I plan to have some layer of acrylic under the LEDs to protect from salt creep and water splashes.

 

[MrReefer]

There is a spray sealant that protects all the equipment and led lights from salt water that you can use.
heres a link to the product
http://www.reefledlights.com/wp-content/uploads/wpsc/product_images/Led_SealrllSM-2.jpg

 

[number1gsxxr]

Oh that's a cool product.