DIY LEDs - The write-up

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Heat Sinks

Heat Sinks

Please remember that I am planning on running at the rated current not the maximum current. But then again this is a 3 up version (3 LEDS per star). However the endostar data sheet has the following statement:

Heat Sinking and Mounting
The Endor has(TM) 6 mounting points for #4 screws. It should be attached to additional heat sinking for proper thermal management. At minimum, a heat sink of a metal plate
(copper or aluminum), attached using a thermal interface material, should be used to increase the area exposed to free air.
The Endor MetalCore printed circuit board has a backing plate that is electrically isolated from the emitter. It is not necessary to use an electrically insulated thermal interface material.

I never tried this lets see if I can give you the web site:
http://www.leddynamics.com/LuxDrive/datasheets/7007-Endor.pdf
 
Re: Heat Sinks

Re: Heat Sinks

<a href=showthread.php?s=&postid=15567965#post15567965 target=_blank>Originally posted</a> by TheFishMan65
d using a thermal interface material, should be used to increase the area exposed to free air.
The Endor MetalCore printed circuit board has a backing plate that is electrically isolated from the emitter. It is not necessary to use an electrically insulated thermal interface material.
Click to expand...

I have one star-mounted XR-E where the negative pad of the LED is NOT isolated from the base of the star. Needless to say, I won't be using it. I'm honestly not sure if it was like that from day one, I discovered it after it had been in use for a week or two.

Given that experience, it's probably best practice to check for continuity between the contacts on the star and the base of the star when doing these builds.
 
So can someone verify my math is correct as I design my oddly shaped heat sink.

With 40 degree optics with the LED being 22 inches from the sand bottom, each LED should at the sand level have a 16inch diameter light.

I want to keep the light off the tank walls so that means in theory from the mid point of the light to the sand it will shine 8 inches forward?


It looks like many are keeping the LEDs about 4 inches or so from the tank edge. Is this keeping the light off the glass?
 
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brocnizer, you have to balance keeping light off the glass (which you're going to do a good job of with optics compared to regular reef lighting, no matter what) vs. a good spread in the tank. If you design the system to have NO light hitting the glass, coverage is going to be really spotty, especially high up in the tank. Just picture the cone of light coming off the LED - if, at the bottom of the tank it's just barely touching the glass, up near the top, it's just gonna be a narrow shaft.

If you're really concerned, you can mix optics - use 40's or 60's everywhere except the LEDs closest to the edges of the fixtures, then put 20's or 40's on those LEDs - a step narrower than what you used in the middle.

One thing I haven't seen anyone do yet is tilt one or more rows. That would let you use whatever optics you wanted, and get the LEDs close to the edges of the tank, without spill on to the glass.
 
Brocnizer, your math is correct but remember that for the FWHM (full wave at half maximum) so there will be light beyond the 8" radii. You may want to use 25 degree optics on the rows parallel to the glass (5" raddii ). Another option is to run a shield outboard of the lens to reflect back the outer light beams. I'm also adding the reflectors which will also block the viewers from seeing the direct light from the lenses & LED's. Jim
 
Thanks for the fast reply. I think I will try the 40 degree optics on all of them for now and maybe do 20's or so in the First row and outer lights.

They are cheap enough to toss if it doesn't work. So My build will be very simple compared to a lot on here. Any final suggestions before I make the parts purchase?

My tank is a corner tank so the LED config and heat sink will be a little different to avoid too much light on the glass. I'm only going to keep zoa coral and a BTA. I think this should be enough light for them.

Also the back part of my tank does not need lighting as it is all rock work up until 4 inches from the surface, hence why only three rows of lights.

I will be buying the big stuff from here and the 7inch heat sink from heat sink USA.
http://www.rapidled.com/servlet/the-9/24-LED-Do-dsh-It-dsh-Yourself-Retrofit/Detail

The proposed setup
http://reefcentral.com/gallery/data/500/219278setup.JPG

A similar Tank
http://reefcentral.com/gallery/data/500/219278fulltank.jpg
 


Does this mean we're close to having a "standard approach" for LED lighting? :lol: [/B]
Click to expand...


To be honest there has been a rapid progression since this thread has been started and I would bet in another year there will be a "standard"

A lot has changed in just the three months I have been following this DIY on different forums.
 
This is getting a little nit-picky, but - while I appreciate what rapidled.com is trying to do by kitting these parts, I have a few complaints. First, they are selling the Q4 brightness bin of XR-E, while most people are using the Q5, which is available elsewhere for about what they are charging for the Q4. Also, the drivers they sell have no dimming capacity. Even if you won't be using some controller to auto-dim the lights, it's nice to have a knob to turn so you can "balance" and blend the colors to your liking, and/or scale back lighting to acclimate corals, etc.

And I definitely agree about the "standard" still being up in the air. Besides us as a hobby getting used to this stuff, the technology itself is changing pretty fast. In another few years, there will probably be LEDs twice as efficient as what we're using now.
 
I'm glad I asked. Thanks for the heads up on that.

I guess I'll go with LEDsupply. Seems others have had good sucess with them unless you know of a better place.
 
81571LEDstars.jpg


Anybody feel like doing a little soldering? :)

Finally received my LED's and lenses from EGT, but I have some time before the drivers arrive so Ill be busy wiring up all these bad boys!
 
<a href=showthread.php?s=&postid=15576564#post15576564 target=_blank>Originally posted</a> by brocnizer
I'm glad I asked. Thanks for the heads up on that.

I guess I'll go with LEDsupply. Seems others have had good sucess with them unless you know of a better place.
Click to expand...

They are good too, but a hair pricey depending on quantities. Probably best to check with ETG if you're going with Crees, they seem to have solid prices but you have to call to order.
 
What size are the heatsinks that you are going with? My next tank will be that same size I believe and have already started thinking about what I would need to upgrade my LED light next time around for light penetration at that depth with haing my array 1" off the water surface.
 
I bought 2 large 40" heatsinks from heatsinkusa and screwed them together! It covers the opening of my tank since I have eurobracing.
 
Interesting. I'm sure that you are going with 40 degree optics for that kind of depth, but how far do you think that you will need to suspend the light off the surface of the water to get good penetration all the way to the bottom? I am going with 5 inches right now to start with since I have a baby clam on the sand bed and with my T5 bulb fixture currently, it seems to be just enough for him right now.
 
<a href=showthread.php?s=&postid=15598740#post15598740 target=_blank>Originally posted</a> by madadi
would these work to control two dimmable buckpucks together??? i can just get the dimmable ones without a pot attached.
thanks

http://www.surplussales.com/Potentiometers/PBM-Shafted/PBM-Shafted-1.html
Click to expand...

are you wanting to controll (2) buckpucks w/ (1) pot?? if so, what you want is called a "gang pot"...the # of "gangs" is the number of different devices it can control, so a 2 gang will do 2, etc
 
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