LED Moonlight DIY

Fabio Iannelli - fabio@kaotica.com

It worked for me, and I am sharing it for you to make what you want of it.
If you have any doubts, then contact a qualified person to help you.

After spending a considerable amount of time online doing all sorts of research on moonlights, I realized that if I wanted a moonlight, I wanted it to act as real moonlight, not just bluish light on my tank at night time. Over the years I like many others set up cheap-o moonlights with 15W blue party bulbs you can get at you local convenience store. I kept that setup for about 2 weeks about 2 years ago. My fish acted restless during that time and seeing it was the only thing that had changed, I went back to what it was like originally, just pitch black at night.

Recently the price of blue LEDs has dropped significantly because a kind Japanese engineer figured out how to make them stable and inexpensively. He got a $200 raise. I feel bad for the guy, but that's a different story...

I started looking about trying to find out the spectrum that I needed to attain to simulate the moon. I found that the spectrum needed was between 470nm and 480nm. Now that I knew what was needed I went and started looking online for a LED that lay in that spectrum. I found many, but most were 464-473 which for me was too low, I wanted to aim for a main value of 475nm. I was able to find one place that had exactly what I was looking for at www.lcled.com I ordered the 500TB4D Super Blue LED. They have a sampler kit of 15 bulbs and I went with that. I was able to print the technical datasheet of the LED from the site and started doing research online on wiring LEDs. Years back I used to play around with LEDs quite a bit, but we're talking more than 10 years ago, so it was time to brush up on some of my highschool physics and college computer hardware skills. (It's not as complex as i am making it out to be) Some will notice that the site says it's a 470nm LED, but if you look at the datasheet, you'll notice that's not quite true. ;-) Either way, 470nm is in the range we are looking for.

I found a great free program called Electronics Assistant from www.electronics2000.co.uk I was using their online version when a pop-up window informed me I could download and install the program, which also has quite a bunch of nifty features. I installed it and figured I needed to have the transformer I was planning on using to know what voltage and current it was putting out. I went to ACE hardware and got a travel transformer which basically allows for a series of voltages from 1 to 12V DC @ 300mA. Just as an FYI-> the transformer was the most expensive part of the whole setup (assuming you don't use all 15 LEDs).  I decided that I was going to run my setup between 4.5V and 6V. I was able to calculate that I needed roughly a 150ohm resistor (thanks to the helpers at www.thesea.org) and that would give me enough play that I could run it at 6 or less and still have adequate power for the bulbs.  I decided to use 5 bulbs to see what they looked like. I can easily add more need be without having to redo everything.

This is what the wiring diagram looks like:  (this was the original one I made, so disregard the questions. Resistors are as mentioned above, and the transformer is a 4.5V-6V not 9 as mentioned in the image.

Image of the resistor package I got at RadioShack:


Once I knew what it was that I needed and purchased everything I started getting ready to assemble.

I recommend doing soldering in a well ventilated area to make sure you don't breathe in too many lead fumes. I used a 30W Soldering iron. Note: this is the maximum wattage iron most LEDs will handle. You'd be better off with a 15W or 25W iron. The max soldering exposure time for the LED is 3 seconds. Warm the iron and and make sure it's reached it's hot mode by testing on some solder, and see how long it takes to melt it.  When you are ready, lay the LEDs in a position you are comfortable with and lay the resistor wire to the anode (the longer of the 2 wires coming out of the LED, the +). Solder the connection. if you are going to do some trimming, do it before you solder, and be careful not to crack the resistor or trim too close to the LED base.  Do this for as many LEDs as you plan on putting on your tank. I made 5 sets. Once I was done, I used speaker wire and soldered the LEDs to those. Make sure the wires are long enough to join each other when you mount them in your canopy!  Tip: Use the Silver or Black wire for the (-) side (the wire coming from the LED), and the bronze or red wire for the wire coming from the resistor (+). This is standard and will help if you ever decide to add more LEDs down the road.

Here is a picture of each node and then a blurry picture of the speaker wire soldered to the node.

Once done, solder the wires together, all positives together, and all negatives together. Make sure you add an extra wire that you will use to connect to the transformer. Tape up the area where the junctions are to avoid having the wires touch. This is what my harness looked like when done:

It looks fugly, but it gets the job done, and will not be seen by anyone.

Next was mounting the contraption in my canopy. I ended up using a staple gun and basically stapled the wires in place. Make sure you do not staple over the exposed wires at each end. I stapled them in place w/ one staple on each side, which anchored the LED in place.

When you have the wire leading down to wherever you want it to go,  connect the wire to the power supply. Make sure you have the correct polarities otherwise you run the risk of burning the LEDs out. Usually on most transformers with the needle looking connector, the inside is the (+) terminal and the outer shell is the (-) side. You can also cut the connector off, and solder the wires onto the harness.  If you have no clue of which is which there is usually a little diagram on the transformer that shows 2 concentric circles, the middle one is the inside and the outer one is the outside of the connector, just look at which is labeled + and -.  It's probably a good idea to test the lights out BEFORE mounting everything in your canopy, otherwise you may have to take it down to replace a blown or malfunctioning LED. From this point you are pretty much done. When it's dark, turn the LEDs on, and see where they point- you will notice they act like mini spotlights. You will have to play a little with the positioning. It was pretty easy for me because the tips of the wires were firmly attached to the canopy, so it was just a matter of bending the bulb to point where I wanted it to shine. Again, be careful not to make the wires touch when doing this.  The LEDs, if wired properly will outlast your fishtank, canopy, and probably you. (Gotta love solid state lighting) Here is a picture of me testing my setup on my tank. This was right when I turned the lights on for the very first time w/o any adjusting:

It's very hard for the camera to capture the exact color that the tank is. I have since redirected the LEDs to shine on specific areas. By the way, it's a 4' 90G tank. Some of what I have noticed since setting it all up: greater polyp extension at night, increased night activity, shrimp spawn and molt more frequently, mushrooms have gotten VERY big very fast, and obviously all corals look different, especially zooanthids. I have the lights set up on a timer, to come on about an hour before my halides turn off(10PM), and stay on till about 4AM.

I hope this write-up helps some of you. Once you have everything you need, it should not take longer than an hour to to everything, and I am sure you will like the result, and at <$20 total, it's hard to beat. Commercial versions of this type of setup go for anywhere around $40 to $150 for just 2-3 bulbs!!! Now, even when you have guests that stay late at night when the regular lights are off, they can still enjoy your tank without bugging you about turning the lights on "just for a little while".  If you have any questions feel free to send me an email and I will try to help you as best I can.



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