SMD LED Build for 2.5G Office Pico Reef

[DenverBC29]

So...

I have another thread going containing my 2.5G Office Pico Reef Build @
http://reefcentral.com/forums/showthread.php?t=2048992

I planned on using a Coralife Mini Aqualight (the old version with 2 - 9W compact fluorescent bulbs) but it runs extremely hot (even after adding a fan and elevating it 1.5" off of the glass). Temp were getting up to 84 degrees, so I scrapped that Idea and I'm going to build a custom LED fixture like one that I built one for a 5 gallon reef bowl a year ago with 4/4 white/blue and it was bright enough to grow coraline algae and mushrooms, zoas, etc. The 4/4 white/blue fixture is going to be utilized to light the fuge on this tank.

This is not the standard Cree LED fixture that you see everyone building, but a 5050 SMD LED fixture, using very small but powerful SMD LEDS that have 3 anodes/diodes each. This is sort of uncharted water, so I look forward to showing the capacity of these LEDS. For shallow tanks, I believe they can be very useful and extremely cost effective (65 cents each).

The fixture will put out about 3watts and I think will be great for a 1.5 Gallon Display in my AIO 2.5G Tank. The whites put out 6000 MCD each and can be found at:

http://www.superbrightleds.com/cat/c...mx5mm,18,1319:

This project will utilize:

Radio Shack Circuit board cut to 7"x3"
8 - 5050 SMD LEDS Pure White @ 6500K
8 - 5050 SMD LEDS Blue @ 465nm
1 - 5V 1000ma Cell Phone Power Supply
1 - sheet of 1/8" Black Plexi for custom fixture (couldn't find a project box that I liked, but use whatever you'd like)
48 - 100 ohm 1/4 watt resistors (you can use 1/8 watt, but the 1/4 watt will run cooler)
1 - 12v rocker switch (i'll try to rob one from an old piece of electronics, but may buy one)
1 - 40mm or 60mm fan (not 100% necessary IMO, but I want my resistors running cool/efficient)
1 - tube of super glue
1 - roll of Rosin Core - Silver Bearing Solder
1 - 40W Soldering Iron (25W would work as well) *use a small tip or file yours down
Etc - hobby knife, electrical tape, liquid electrical tape, screws, drill, drill bits, tweezers, screw drivers, and probably other various tools


Wiring Diagram:

[DenverBC29]

Cut the board to the size wanted and laid the LEDS out as a test fit. These LEDS are small, so get your tweezers!


Here is a close up of how I like them to sit on the board. There are 3 anodes (+) on the right and 3 cathodes (-) on the left. You can see a small notch in the upper left hand corner of the LED, this indicates that the left side is the Cathode (-) side. They are not glued down and are not completely square, but when they are, I like to have the center contact on each side line up with the nearest adjacent hole and the upper and lower contacts line up, somewhat offset.



I used a tiny drop of super glue on each LED and glued them in place which will make soldering easier and assure that they end up exactly where I want them. This fixture is wired parallel, so it will make soldering easier. Use this calculator to design your circuit and identify correct resistors to use
http://led.linear1.org/led.wiz
I laid a piece of wire (I gutted some Cat5 that I had laying around to use the individual wires inside) out because it will be stripped from the top LED to the bottom LED and soldered along the entire right side.

[DenverBC29]

Stripped the wire long enough to reach the top contact on the top LED and the bottom contact on the bottom LED. I laid my tweezers on the wire or use tape as it would work better, and I began to solder. It only takes about 5 or 6 seconds to get it hot enough before you push your solder onto it.


The 2nd one looks better than the 1st one, but they both work. Just work your way down the board and get them all soldered up.


Right side done (anode or + side). I use a 3volt power supply to touch each lead and make sure all of the connections work. The 4th one from the left was a pain (the middle circuit wouldn't light up) so I had to hit it, and hit it, and hit it before it tested working. Ended up ugly, but it works. TEST AS YOU GO, IT WILL SAVE YOU TIME! Most of this will be covered up by liquid electrical tape, so don't worry of your leads aren't pretty, just make sure they work!

[kcress]

Looking good!

[DenverBC29]

Thanks kcress!

[DenverBC29]

Time to solder the anode side of the other row. First step is to strip a long piece of wire, just like the first side. Then tape or hold the wire in place with something. First couple are soldered. Some turn out prettier than others.


Time to test the leds. I like to use a 3 volt power supply because the leds can take all 3 volts and you don't need resistors to do a quick test.


Plug in your 3 volt power supply and place the positive lead under your positive strip of wire that was just soldered.


Then touch the negative lead to all 3 diodes on each led. Each diode should make the led light up, if not, check your soldered connection.


That's it for the anode side of the entire fixture. When my resistor shipment comes in, I'll solder a 100 ohm 1/4 watt resistor to each diode of every led. A total of 48 resistors will be soldered into place.

[DenverBC29]

Here is an example of these leds being used as moonlights. This is 1 blue smd led on my biocube 29 with only 1 of the 3 anodes hooked up. It could be 2 or 3 times brighter if I hooked up the 2nd and 3rd anode.

[Egres]

thats pretty sweet denver

i've never look at doing led because i tough its was harder to do but the way you explain it and will all the picture you can't go wrong man great job ..... sow i'm guessing if someone want to do a dawn dusk effect he could wire the blue and white one separately ? and put them on different timer as well just i anode some where to do the moonlight ?

[Egres]

just wondering those 16 leds would be worth what compare to T5 or MH ?? do you know

[DenverBC29]

Egres - thanks! You've got it! The wiring would be a bit different as you'd have to keep the anode circuits separate from the blues and whites, but if you wanted to get creative you could wire it in stages: have a few blue come on, then a few more blues and a white, then all of them, then reverse order till dark.

As far as the moonlight. The size of tank will determine how you utilize the light. In my 5g reef bowl, I used 1 anode and put a piece of paper over the blue because it was too bright. In my 29 biocube, i used 1 anode and no paper. I've been playing with these for a while and would be more than happy to help you plan your design.

A far as comparison to other bulbs, thats a tough one and I'd love some suggestions from others. I think this fixture will compare to a cree led fixture where the crees are driven at 1/2 to 3/4 of an amp. I'd only recommend these leds for small or shallow tanks unless you want to solder up a very large number of them. What size tank are you thinking about?

This fixture is 3.136 watts and will put out around 131 lumens of white and around 31 lumens of blue. I believe these numbers to be a bit misleading of actual output usable to corals because it only measures part of the light spectrum that is visible to the human eye. Anyone more knowledgeable want to chime in?

[Egres]

cool i was thinking maybe a 15 or 10 gallon similar to what your doing with your 2.5....im assuming you have to cover those led from the water ??

[DenverBC29]

You could probably use this type of application for a tank that size. Keep in mind that led reef lighting is still somewhat of a controversy as to its long term effectiveness in keeping healthy corals. I haven't seen a build like this, using these type of leds, so build at your own risk. this is a bit of an experiment.

For a ten gallon, I would use around 35-40 whites and an equal number of blues for a total of around 80 leds. That is a lot of connections to solder, but could be doable. Maybe just make 4 or 5 led arrays like I am building here and you'd be set.

You definitely have to have a glass or plexi cover on either the tank or the light fixture. Saltwater reacts violently with electricity!

[Egres]

what would be the difference between this and with the cree led ?? as far as build up and gear i need to make it work..if ya know

[DenverBC29]

A lot of differences. With the cree leds, you will need aluminum heat sinks to mount the leds to, fans, power supplies and led drivers. It is a lot more expensive, but they are more powerful. I'd suggest them with a tank over 10g. Search for cree on here and you'll find several detailed builds.

[DenverBC29]

My resistors came in today from http://www.thaishine.com. They were $2.50 for 100 1/4 watt 100 ohm resistors. Free shipping too! $2.50 at radio shack will get you 5 resistors for that price.


Step 1 - use a razor knife and cut/scrape each diode to ensure that no super glue ended up on it and that you'll have a good connection.
Step 2 - mark the mid point between your leds with a marker or pencil
Step 3 - trim about half of one of the tails on each resistor to be used. The short end that you just trimmed will go up from the back side of the board to the nearest or 2nd nearest hole from each diode. The other end will come up through the center point in the board that was marked. Tweezers are very handy during this stage.

[DenverBC29]

Here is a view of the back side. I trimmed the shorter side if the resistors at varying lengths so that the resistors wil be staggered, possibly keeping them cooler.


Line up each resistor tail to each diode with tweezers, then solder into place. This side is more difficult to solder because unlike the anode side, each diode needs to have it's own individual connection. Be careful and take your time!

[DenverBC29]

Remember to use your 3 volt power supply and test your connections after each led!

[theatrus]

Looks good.

I did a complete overkill on my 7.5G AGA cube, however everything coral in it is quite healthy. Its composed of 16 LEDs (8 XP-G, 8 XR-E), but running well under max current.

[DenverBC29]

Thanks theatrus. this is round 2 for me experimenting with these leds. Things went well the first time, so I'm doubling the number of leds in a much smaller tank. If it doesn't work out well, I'll be putting some crees over it. It is a 1.4 gallon display, so I think 1 white and 1 or 2 blues will do it.

[DenverBC29]

To get the staggered effect on the resistors, I stagger them then cut them at one time. This may or may not help keep them cool, but it will not affect anything negatively.


It's not beautiful, but it works. =)


I failed to get 3 of the 48 connections working properly, so 2 of the blue and 1 of the white will only light 2 of the 3 circuits. I'm 99% certain that I applied too much heat when soldering those failed connections. Be careful and apply heat for only a few seconds because these are touchy! 45 out of 48 isn't bad though. If it ends up bothering me, I will order more and replace them, but I doubt that I will miss the 2800mcd that will be left dormant.


Next step will be to trim/solder all of the long resistor tails to a single stripped wire for the negative circuit of the fixture.

[Egres]

looking sharp looking sharp !! can't wait to see it light up !!

[DenverBC29]

Thanks Egres. I'll be getting the negative lead soldered this evening and plugging it in for a test run. You know I'll post pics...

[DenverBC29]

Time to wire all of the resistors to a common ground wire. I stripped a long piece of insulation off to give me enough wire to connect all of the resistors. I spread apart all of the resistor leads and laid the common wire down the middle. Then, one by one I crossed the leads over the ground wire, then trimmed the resistor leads just above the ground wire, and soldered them in place.



Here is what it looked like after I crossed the leads over the ground, trimmed them short and soldered them in place


After I worked my way down the entire fixture, soldering each resistor to the ground wire, it was time to test. I hooked the positive (anode) wires and the negative (cathode) wire to my 5v, 2amp power supply, and viola! Blinding led light!

[DenverBC29]

I covered the front side of the circuit board with electrical tape to insulate all the open connections. The back side where the resistors reside was left untaped to ensure proper cooling


I would suggest starting this project with a circuit board and project box combo to allow for easy fit and finish. Since I chose not to, it was time to build a custom enclosure. It is made from plexi glass and leaves room for a 12v 80mm computer fan. The fan will be running off of the led's power supply, so it will be running at 5v, not 12v. It runs slow, silent, and still moves plenty of air!

[DenverBC29]

LED fixture is done!


Looks like similar light output to my HOT coralife 18W compact florescent fixture.