Moon lights

[Mr_Cool]

I saw Bug Power's write up on the DIY moon lights, and it was pretty helpful. It convinced me to buy some LED's, too. But, I think I need a little more help.

I have the LED's, as well as some speaker wire. (I thought I read somewhere that it would work just fine.) I also have a bunch of old power supplies. (I have a 30v, 12v, 9v, 5v and 3v.) I don't really understand a whole lot about electronics, though.

I'm looking for suggestions on what to do with moonlights on a 55 gallon. I have plenty of LED's, and wire. Not sure about hooking them up in series or parallel, though. From what I've read, I could probably go either way with it based on the stuff I have. I just want to do what would be easiest and/or most economical.

Could I put 30 LED's in series on the 30v power supply, thereby giving each LED 3v? Or, would it be better to go with the 3v supply in parallel, and use as many LED's as I need/want? I'd rather not have to fool around with resistors or anything.

Can someone give me some ideas?

[alton]

If you hook anything up in series if one goes out they all go out, like the old christmas lights. And like the new cheap Christmas lights.

[Mr_Cool]

Does this mean parallel is better? I'm thinking,"If it's done right, I won't need to worry about one light going out."

[hobogato]

i did mine parallel, but there is a resistor for each bulb. radioshack carries them for cheap. BTW, I have about 70 bulbls on my 240 and it looks really cool at night - you are gonna love it!

[Mr_Cool]

I forgot you had those, Ace.

How many bulbs would you use on a 55 gallon? And, what about your power supply? Is it 12v or what? The way I understand it, you can go with a lower voltage power supply when you connect them in parallel because each bulb is getting the full voltage of the supply. If they are 3v LEDs, I could use the 3v power supply, right?

Someone who knows electronics please chime in. I'd like to work on this over the weekend if possible.

[Bug_Power]

They sell UV LEDs too....it's an actinic purple color. Basically the easiest cheapest fastest way to do it is in series. This means EVERYTHING is on one line. Cut that line anywhere down the line, and the circuit goes out. With that said. I didn't want to run 10x the wire and 10x the resistors (plus I didn't have the correct resistors) so I just did mine the way I did. Running in parallel makes each light it's own circuit meaning if you blow a bulb everything else works. It's a matter of personal preference. LED's last for Huundreads of thousands of hours....don't plan on replacing any soon.

Depending on the LEDs you get some of them are 3v or close. You'll find some 12v and inbetween as well. To find how many LEDs you can run on the powersupply simply divide your powersupply's voltage by the voltage of the LEDs. 30v/3vled=10 LEDs Pretty simple.

[hobogato]

i know those LEDs are supposed to last a long time, but on my original setup (40 bulbs), only half are still working. the salt air really attacks the wiring at the base of the LED. so when i moved everything to the 240, i just added 50 new ones to get to my total. i run two 12v power supplies - half of the LEDs on each one.

as far as getting the right resistor - ?? i bought mine as a set on ebay including the resistors.

[Bug_Power]

yeah I just keep adding LED's until one of the resistors I have work. To keep salt air off them put them in a tube for T8 lights. They sell them at home depot then just silicone the ends shut.

[SBreef]

When I have a little more time, I will post more info. Just no time right now.

[Mr_Cool]

Thanks guys.

I'll be looking for the info, Roy.

[SBreef]

Sorry for not getting back to you sooner.
Where did you buy the LEDS? Are these the super bright type. Standard LEDS will not be bright enough.
BTW, I think that the Blue are only super bright, but I could be mistaken.

Do you know what the voltage and current rating of the LEDS is?

You can use any of the power supplies that you listed above. What would change would be the current limiting resistor that you would use. And the number of LEDS that you can use, for the current rating of the power supply.
You can use the speaker wire to wire in the LEDS.
You want to wire the LEDS in parrallel. Even though, LEDS rarely burn out, wiring them in series would give you problems if you should have a problem with connections or a bad LED.
You do not need a resistor at each LED. You only need to have one wired in series with either the positive or negative side of the power supply, as long it is the correct value and wattage.

As for the corrosion factor due the salt air around them, once you have soldered them in, just put some silicone around the connection. What I have done in the past for outdoor connections is, split the wire into two parts. Get some heat shrink tubing of the correct size for the connection, solder the connection, put some silicone on the connection, slide the heat shrink tubing around the connection, heat up the shrink the tubing over the silicone and connection. Yes, some silicone should squirt out. Then you are done.

If you have any questions, just ask.

[Mr_Cool]

I've been playing with them. I cut off the end of one of the 3v power supplies and touched the wire to the leads on an LED. It shined pretty bright. BTW, the LEDs are bright blue and need like 3.2v. Do I need a resistor with the 3v supply if I connect them in parallel?

I checked how it looks at night with the lights off. Wow! The corals just glow. Can't wait to get these hooked up.

Thanks for the info!

[SBreef]

Yes, I would still put on a current limiting resistor. I just checked a site, and they recommend a 15 ohm, 1/8w resistor. You can use a 1/4w resistor. Go to radio shack or an electronics parts house and pick one up. At a parts house, it only cost about 10 cents. This is just to keep from over powering them.
On the site I used a 3.5v supply, 20ma Leds and operating voltage of the LEd of 3.2v

[SBreef]

BTW. what is the voltage and current rating of the power supply?

[Mr_Cool]

Okay. I'm not sure what all this means but the back of the power supply says...


Class 2 transformer
Model No.: DC30300
Customer No.: A9031
Input: AC120v 60 Hz 3W
Output: DC3v 300mA


The LEDs have and operation voltage of 3.2v - 3.6v
Reverse current of less than 30 uA
Max power dissipation of 80 mw
Max continuous forward current of 30 mA

Like I said, I'm not sure what all that means.

I didn't get to play with them today. My soldering gun doesn't seem to be working. (Or, I'm not doing it right.) I've never used one before. It was my grandfather's, and somehow I wound up with it. I'm going to borrow one from a friend this week and try again.

Thanks for all the help Roy!

[SBreef]

Class 2 transformer
Model No.: DC30300
Customer No.: A9031
Input: AC120v 60 Hz 3W
Output: DC3v 300mA


The LEDs have and operation voltage of 3.2v - 3.6v
Reverse current of less than 30 uA
Max power dissipation of 80 mw
Max continuous forward current of 30 mA

Before I forget, you said that you were having problems with your solder gun. Is it a gun or an iron? I might be able to help you with that too! What brand?

OK! For the LEDS. You need a different power supply. That supply willnot be able to produce enough voltage/current to get the max from your LEDS.
The reason is this, the power supply will only put out about 3 volts with a load. Now, your LEDs have a operating voltage of 3.2 - 3.6, that in itself would not be able to provide the proper voltage to get the max out of your LEDs.

Reverse current, is how much current it takes to "Blow" the LED should you hook it up backwards.

Max power dissipation, that it the power used/heat produced by the LED.

Max cont. forward current, that is the amount of current used to light the LED.

Now with the above number of max forward current, and your power supply, you could only hook up 10 LEDs to the power supply.

I would look for at least a 5 volt power supply. You need to remeber that the wall transformer type power supplies, will do just fine, but they are not very well made, and voltage/current specs are not always correct.

Next question, how many LEDs are you wanting to use?

Remember, that if you use a power supply larger than what your LEDs require, you need a current limiting resister. You can use any DC supply that you want or have, you need the proper current limiting resister.

[ratboy]

I know for a large tank LEDs can be pricey or at least alot of work to wire up. I went a different route with my 380 and used cold cathode tubes like you see in some computer cases that light up. I bought mine for 10$ online but I've seen 2 tube setups at Frys for < 15$. The only thing I had to do was find an old AC/ 12v DC convertor and hook it up to the wires that goto the computer power supply. I get a nice, uniform blue glow over 90% of my 7' tank with 2 x 12" CC tubes. I gobbed some silicone anywhere there is potential for salt creep and they still work fine after ~ year.

http://www.crazypc.com/Merchant2/merchant.mv?Screen=PROD&Product_Code=8240B

[Mr_Cool]

I have a bunch of old power supplies. If I use the 5v supply, how many lights can I use? I have 100 or so.

Can I get a current limiting resistor from Radio Shack? I would think I could, but you never know.

Just to make sure... A 5v power supply is more than enough to power the lights. If they're wired in parallel, it won't matter how many lights I use, either, as long as the voltage of the power supply is > the operation voltage of the LEDs. That's why I'd need the current limiting resistor. Right?!

[SBreef]

You need to limit the amount of current to the LEDs, that is why you use a current limiting resistor. The number of LEDs depends upon the current output of the power supply, ie; say for instance the supply is rated at 5v 450ma, your LEDs are rated at 3.2v 30ma, with the proper resistor you could run 15 LEDs.
15(LEDs) x 30ma (for each LED) = 450ma. Again, with the proper resistor

[Mr_Cool]

I'm confused. (Not dumb, just confused!) Check out this site..

http://www.theledlight.com/ledcircuits.html

Skip down to the part about wiring in a parallel circuit. Does this mean that in a parallel circuit, each LED will get the full 3v but the current will be split evenly among the number of LEDs? (I think I'm getting it, now.) That's why my 3v power supply could only have 10 LEDs powered. (The current on the supply is 300 mA, but each LED needs 30, right?)

So, if I want to power LOTS of LEDs, what I really need is a power supply that with an output of 3000 mA? This would mean that (if it were a 3v supply and each LED needs 30 mA) I could wire all 100 LEDs.

Am I confused or stupid?

[SBreef]

You are correct.

[Bug_Power]

Right in parallel it's mostly your currenty you need to worry about, in series your voltage has to add up.