Cintax

My DIY Led Build

Well hello! I have decided to make up a DIY LED fixture for my reef aquarium. I bought the components from various places, basically wherever they were cheapest. Tank dimensions are 36" by 18" by 15" deep. Because the tank is so shallow, I have decided not to get optics now, this might change, I will have to see how everything looks.

 

Major Components:

 

HeatsinkUSA 5.886" x 25.5" Aluminum Heat Sink (1)

IMG_0343.JPG

 

Mean Well ELN-60-48P Constant Current Drivers (2)

IMG_0345.JPG

 

 

Cree XT-E Royal Blue LED (24) supplied by LED Group Buy

IMG_0349.JPG

 

Cree XP-G Neutral White LED (12) supplied by LED Group Buy

IMG_0357.JPG

 

Thermal Tape Pre-Cut (36) supplied by LED Group Buy

IMG_0348.JPG

 

 

Controller:

 

DIY Arduino Driven Controller

IMG_0358.JPG

 

 

Tools:

 

Weller WES51 Soldering Station

Side Cutters

Wire Strippers

DMM

 

 

Design Aspects:

 

Well alright, a word about the design of the controller. I have been working with Amtel microcontrollers for awhile now. I like them because they are cheap, and easy to program. In the above picture you see three boards. The larger blue one is a development board. You would wire your circuits up on solderless bread boards and then connect jumper wires to the pins. The tiny blue one in the middle is actually the same as the larger one but only acts as a breakout board with no on board power regulation. The one on the right is the prototype board complete with the RTC and headers for a temperature probe.

 

This controller already has provisions for ATO, Wavemaker, Temperature Probe, LEDs and Water Level as part of the design. I am going to start with the LEDs and move on from there. In the software the foundations are already laid down for the extra additions later.

 

With respect to the LEDs, I plan to drive the XP-G NW LEDs at the stock 1300mA provided by the Mean Well drivers in a single series circuit. As for the XT-E Royal Blue LEDs, it gets a little more complicated. My plan is to run two parallel strings of twelve LEDs each. According to Kirchhoff’s Current Law, the total current is the sum of the currents through the individual branches. In this case the total current is 1300mA so that means there should be about 650mA available to each string. The current rating for these LEDs is only 1000mA so a failure of either parallel string will likely result in fried LEDs. As such I plan to employ, at the very least, fast blow fuses on each branch of Royal Blue LEDs. I am also toying with the idea of using a current mirror circuit to balance the current as well as offer another way shut down the LEDs in case of individual component failure.

 

I plan to suspend this fixture from my ceiling using braided cable or something similar. And I have a line on a fellow who will do plastic work for the cost of the materials. If that's the case, I may end up with a fancy little enclosure as well.

 

That's it for now, I'll be back updating as I go.

Edited by Cintax

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Very cool, I am interested in the cost for parts at this point.

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A breakdown of cost is as follows:

Heatsink - $45 (Heatsink USA)

LEDs and thermal pads - $180 (LED Group Buy)

Drivers - $26.30 each (PM if you want to know the supplier)

 

Everything else such as the Arduino, wires, solder, tools, etc. I already own as I have an active electronics hobby.

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nice leds,i wish i could go with crees :(

how big is the tank that these are going over?

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I should have included that above, the tank is 36" by 18" by 15" deep. Because the tank is so shallow, I have decided not to get optics now, this might change, I will have to see how everything looks.

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So, I whipped this up on AutoCAD last night. This is my proposed layout. The larger space between groups 3 and 4 is to accommodate my center support. What does everyone think? Does anyone have experience with 5.886" heat sink from HeatsinkUSA and using a layout like this?

LED_layout_Model.pdf

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From personal experience I would say the only time that grouping them like that is beneficial is when you are putting optics on them... tried it like that a few times before and got some wierd spotlighting effects. Fixtures you see using that arrangement typically use a collimating lens so the colors are being blended at the source.

IMO, you would be better off going with rows... alternating your blue and whites. There is enough overlap on the light output that you'll not just get a good blending on the colors but you'll get a more even coverage of the tank. Just leave a little larger gap between the rows to accommodate your tank brace.

 

The 5.886" heatsink you speak of, 3 rows of ten, whites and blues alternated. You of course would have 3 rows of 12 but you get the idea....

P1010204.jpg

 

 

Whole tank with even coverage and not a hint of any color separation (disco ball effect).....

 

P1010222.jpg

 

Don't mind the somewhat "washed out" look on the color of the lights... my cheap little camera does NOT like LEDs. In person it's awesome...LOL

 

 

Steve

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Thanks for the input Gazer. I am considering using a layout like you suggest as well. I do not know yet if I will need optics, so my reasoning behind the above grouping is that I can easily add optics without spotlighting. If I have tonnes of spill out that's wasted light and I'd like to be able to focus it a bit if needed. I also don't know how high I will have this fixture from the surface of the water. I was thinking 6-8" from the water surface so that it is easier to work in the tank if needed. This is another reason I might need optics. Nothing I keep needs a lot of light though so maybe this won't be a problem. All of the above are the reasons I haven't advanced on this even though I have all the parts I need. :/

 

BTW, are most people using 18ga or 20ga wire when connecting their LEDs?

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I have analysis paralysis on this. /sigh.

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Thanks for the input Gazer. I am considering using a layout like you suggest as well. I do not know yet if I will need optics, so my reasoning behind the above grouping is that I can easily add optics without spotlighting. If I have tonnes of spill out that's wasted light and I'd like to be able to focus it a bit if needed. I also don't know how high I will have this fixture from the surface of the water. I was thinking 6-8" from the water surface so that it is easier to work in the tank if needed. This is another reason I might need optics. Nothing I keep needs a lot of light though so maybe this won't be a problem. All of the above are the reasons I haven't advanced on this even though I have all the parts I need. :/

 

BTW, are most people using 18ga or 20ga wire when connecting their LEDs?

22awg

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Well, the problem is that 22awg has a maximum current rating for 7amps open chassis but only 920mA when used for transmission. I suppose I could use 20awg run from the driver to the heat-sink, then the smaller 22awg smaller for distribution between LEDs.

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Well, the problem is that 22awg has a maximum current rating for 7amps open chassis but only 920mA when used for transmission. I suppose I could use 20awg run from the driver to the heat-sink, then the smaller 22awg smaller for distribution between LEDs.

 

If you decide to use optics, you probably won't be pushing more than 700mA anyway.

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Always design with safety margins. Safer that way

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Does anyone have experience with the operationing temperature of Mean Well drivers?

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This is my proposed layout for my LEDs. I have 2:1 Royal Blue to Neutral White

 

 

 

Option 1:RB	RB	RB	RB	RB	RB	RB	RB	RB	RB	RB	RBNW	NW	NW	NW	NW	NW	NW	NW	NW	NW	NW	NWRB	RB	RB	RB	RB	RB	RB	RB	RB	RB	RB	RBOption 2:											RB	NW	RB	NW	RB	NW	RB	NW	RB	NW	RB	NWRB	RB	RB	RB	RB	RB	RB	RB	RB	RB	RB	RBNW	RB	NW	RB	NW	RB	NW	RB	NW	RB	NW	RB		Option 3:									NW	RB	RB	RB	NW	RB	RB	RB	NW	RB	RB	RBRB	NW	RB	NW	RB	NW	RB	NW	RB	NW	RB	NWRB	RB	NW	RB	RB	RB	NW	RB	RB	RB	NW	RBOption 4:											RB	NW	RB	RB	NW	RB	RB	NW	RB	RB	NW	RBRB	NW	RB	RB	NW	RB	RB	NW	RB	RB	NW	RBRB	NW	RB	RB	NW	RB	RB	NW	RB	RB	NW	RB

 

What do you guys think?

LED_layout2.pdf

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This is my proposed layout for my LEDs. I have 2:1 Royal Blue to Neutral White

 

 

 

Option 1:RB	RB	RB	RB	RB	RB	RB	RB	RB	RB	RB	RBNW	NW	NW	NW	NW	NW	NW	NW	NW	NW	NW	NWRB	RB	RB	RB	RB	RB	RB	RB	RB	RB	RB	RBOption 2:											RB	NW	RB	NW	RB	NW	RB	NW	RB	NW	RB	NWRB	RB	RB	RB	RB	RB	RB	RB	RB	RB	RB	RBNW	RB	NW	RB	NW	RB	NW	RB	NW	RB	NW	RB		Option 3:									NW	RB	RB	RB	NW	RB	RB	RB	NW	RB	RB	RBRB	NW	RB	NW	RB	NW	RB	NW	RB	NW	RB	NWRB	RB	NW	RB	RB	RB	NW	RB	RB	RB	NW	RBOption 4:											RB	NW	RB	RB	NW	RB	RB	NW	RB	RB	NW	RBRB	NW	RB	RB	NW	RB	RB	NW	RB	RB	NW	RBRB	NW	RB	RB	NW	RB	RB	NW	RB	RB	NW	RB

 

What do you guys think?

 

I am thinking of doing my own similar LED setup, did you ever go on with this?

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I am thinking of doing my own similar LED setup, did you ever go on with this?

 

I did. I just never updated this thread. I went with clusters but in retrospect I'd like have gotten better blending with spacing them evenly.

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I actually used 18ga from driver to heatsink and 22ga from led to led....22ga led to led in 1-3inch runs should easily support upto 2a, while the longer runs from the heatsink to drivers(5ft) for me I used 18ga...

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Nice build. My biggest struggle so far on my build is getting my rtc to work.It keeps time but I have no idea how to make my lights come on with it.Good luck with your build.

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