calling all electricians

[Kuhlifan]

I'm doing an experiment with LED lights for accent/fill in lighting for a tank. I recently bought some small waterproof LED arrays off ebay. I will have six lights, each with 3 LEDs. There will be two green, two white and two blue. The best power description I found was 12VDC. There is no mention of amperage.

I don't know what sort of connector is on the wire, I'm guessing none. I plan to adhere these to the inside top of my hood (the stock flourescent light is a little weak). The two white and green will go together to provide more light and maybe enhance the color of the plants a little. The two blue will be separate to act as night/moon lighting.

Here's my thing, I don't know how to connect them exactly. I'll probably take an old ac adapter and cut the plug off and simply wire it up that way, but I'm not totally clear on how those work. If I have the four three LED strips (two greens and two whites) wired together and the two blues wired together, what size adapter would be good for each set? Do ac adapters self regulate, i.e. if I get one that provides more current than necessary, will it only send what the lights need or will it flood them with too much electricity? Is there any sort of distribution block, for lack of a better term, that I can connect them to to control them, or just plug/unplug the ad adapter?

 

[ElBoltonero]

The adapter should have two ratings - the voltage and the wattage. The voltage will need to match the lights - if they're all 12v you're good. Each electrical device will also use a certain amount of power at 12v (volts is the strength of the power). As long as the power requirement for your light strings isn't over the wattage your brick puts out you should be fine. Any extra supply of power will be ignored (they take what they need and the rest moves down the conveyer belt). If the lights draw more power than the brick makes available then they may not work at all or be dimmer than normal.

So if, for example, your brick is 12v, 20w and you have 3 12v 5w lights...
The strength of the power is 12v, which is what the lights require. The brick makes 20w of power available for use, your lights need 15w (3x5w). You're good.

If your brick is 12v 20w and you have 3 12v 10w lights...
Strength of power is fine again, obviously, but you only have 20w of power available and you need 30w (3x10w). Not good.

When you wire them together make sure you do so in sequence...the power should make a big loop around from start to finish. The power out wire from the brick should attach to the power in wire from the first LED set, and the power out from the first LED set should attach to the power in wire from the second LED set, etc., until the last LED set's power out attaches to the brick's power in. (don't worry about which is "in" and which is "out"...it's AC so it constantly flips anyway...just make sure your end result is a loop and not a tree)

I'd recommend soldering them and then putting a good heat shrink wrap around the exposed wires due to the aquatic usage of these. And you could just hook the bricks up to timers, or get a day/night aquarium timer.

 

[wesleydnunder]

Typically, these hi-power LEDs use DC power supplies and not AC wall adapters. You can look online for wiring diagrams which are specific to your LEDs.

Here is a link to some typical configs: http://reefledlights.com/wiring-diagrams/

Mark

 

[vequalsir]

It's a little more complicated than the two posts above.

You will need to know the specs of the led's to begin with. Do you have a link to what you bought? Most high power LED arrangements will not use a typical power supply to light them. The use a constant current supply.

A constant current supply will vary the output voltage to maintain it's rated current. Your supply will need to develop enough voltage to forward bias the led string and drive enough current to run the led's. Check out rapidLED.com and LEDgroup buy for more information.

We also have some DIY's here in the forum as well.

good luck and post some photos of the project

 

[Kuhlifan]

OK, finally, I have my lights.

Starting out, I bought some small leds used for car accent lighting. Each unit came with a total of six leds, but was designed to be cut in half and used as a pair of units with three each. Right after I bought them, I realized they were a lower output style of light, so I went back and looked for something heftier. I ended up with a series of lights that come in four leds a unit. There are four of these units connected together.

So here's my plan. I want to put the four high powered units (white light) together with a pair of the low powered units (green color to accent plants) to brighten my tank, which is sort of dull and dim with the factory lighting. Since the tank is an "all-in-one" that uses a proprietary bulb, there's little I can do to improve on the stock lighting. I also plan to do a separate circuit, if that's the word, with a pair of the lower powered leds (in blue) to create a moonlight.

Attached is a photo of the tank with the lid off, and a photo of the high powered leds and one of the low powered pieces. I'm still fuzzy on power issues, but I bought a pair of power supplies from the company that I got the lights from that, if I understand them correctly, will run the lights. We'll see how that turns out.

The big issue now is determining how to mount them in my tank. I'm thinking of "hanging" something over the edge of the filter (you can see the filter in the tank shot) that I can attach the lights to. My only other choices would probably have to be either removing the stock light completely, if possible, or finding some sort of external filter to replace the stock one so I can attach something where the filter once went. I was thinking of maybe getting a small piece of plexiglass and bending it so that one side would "hook" over the top of the filter, then bend the rest to make a "shelf that I can just sit the lights on to shine through. Thay would help protect them from splashes, but might subject them to pooling water from condensation. I'll have to see what I can find.