LED as main light

[Worldwithin]

Obviously it currently does not have a housing which I am in the process of trying to figgure out what to build it out of, but one of the few things that I probably would do differently is use a thicker PC board. The one that I used for this is rather thin and flexes quite a bit which disturbs the soldering and connections causing some of the LED segments to power down.

The general setup for this all consists of multiple rows of 3 LEDs each with a 68 ohm resistor to bring the voltage down enough to about 4 vdc per LED. I alternated the white and blue LEDs to broaden out the colors and to hopefully allow better color dispersion. I guess we shall see!

Andy

[Worldwithin]

Sorry for the additional post, the initial one that I posted did not add the final image of the LED array above my sump.

Here it is.

[chucklez]

wow, i did a google search and found 21000 MCD ultra bright LEDs. Thinking about ordering some to try out on a mini reef to see if LED lighting is applicable.

[chucklez]

Originally posted by Worldwithin
I think that the power supply was the biggest issue as the total array uses 12vdc at close to 2+ amps. Finding an affordable power supply for this was interesting, luckily I managed to acquire one from work that is rated at 6 amps if I ever decide to add a second array to this one.

If I can ask, what would a power supply like that cost for an average joe like me?

[dcoufal]

Originally posted by chucklez
If I can ask, what would a power supply like that cost for an average joe like me?

I always pick up power supplies from: http://www.allelectronics.com/cgi-bi...480&type=store

20 VDC 3 AMP SWITCHING POWER SUPPLY - $14.00
12 VDC, 1 AMP SWITCHING POWER SUPPLY - $6.65
12 VDC 3.5 AMP SWITCHING SUPPLY - $18.00
12 VDC, 8 AMP POWER SUPPLY - $27.50

They all seem pretty cheap to me.... the 12VDC/8AMP will work for my 125gal project.

[Worldwithin]

If I recall all the power supplies listed previously are manufactured by a ELPAC as was my power supply. I think they run in the $20+ range depending on size and amperage. They work pretty well and do a darn good job of conditioning the power as it passes through them which helps prevent LED flickering. The only issue with them is their size. They are rather large, I think roughly 8 x 4 x 2 inches.

[Worldwithin]

They all seem pretty cheap to me.... the 12VDC/8AMP will work for my 125gal project

Doing the math, at roughly 20 milliamps, this would result in an array of only 400 LEDs assuming that nothing else is consuming power like fans or such. This is going to be a small array for a 6 foot tank. The array that I built with 90 LEDs is only 8 x 3.5 inches, barely enough to cover 15 inches of my sump. If this is going to be your primary lighting array, I would suggest that you probably make 2 or 3 of these arrays to cover your tank.

[dcoufal]

Originally posted by Worldwithin
Doing the math, at roughly 20 milliamps, this would result in an array of only 400 LEDs assuming that nothing else is consuming power like fans or such. This is going to be a small array for a 6 foot tank. The array that I built with 90 LEDs is only 8 x 3.5 inches, barely enough to cover 15 inches of my sump. If this is going to be your primary lighting array, I would suggest that you probably make 2 or 3 of these arrays to cover your tank.

I didn't say I was only going to use 1....
It's much harder to find a higher amperage power supply for a low price. Besides, multiple power supplies leads to greater redundency. And, my 125gal is a freshwater tank that currently only has 160W of NO lighting.

[chucklez]

Ok, My LEDs that I have purchased should arrive later this week, And I have a few questions if someone could point me in the right direction.

1.) I need to find a wiring schematic for 70 of the LEDs. Anyone have one?
2.) What type of power supply (wattage) should I use.
and,
3.) How closely would you space the LED's?

Any help is appreciated guys.

If anyone else is intereested in the LEDs, the website is http://stores.andale.com/hdtech

[Worldwithin]

1.) I need to find a wiring schematic for 70 of the LEDs. Anyone have one?

How do you plan on wiring them to begin with? I created my own PCB (printed circuit board) and then etched the copper board and drilled the numerous holes. The alternative to printing your own boards is to get a pre-drilled / plated board where you can solder the LEDs to it, but then you have to connect all the wires yourself because there are no traces - this method is kinda easier, but very messy looking. Printing your own board takes time and a bit of practice / knowledge of what to do.

2.) What type of power supply (wattage) should I use.

The power supply really depends on how many LEDs you plan on chaining together. I used a 12vdc (13.3vdc actual output), 6amp (72 max watts) power supply. I connected it from the positive voltage side to a 68ohm resistor to a 3 LED series then to negative. The resistor drops the overall voltage down slightly to give each LED approxmately 3.7 or so volts each. Since I am running 90 LEDs at 20 milliamps each, I require a power supply with at lease 1.8 amps of output.
You could use whatever sized power supply you want, but it depends on if you plan on running them individually or in a series. The thing I would primarily look for is the amperage of the power supply. Since you stated that you are running 70 LEDs, if they are at 20 milliamps each, the minimum output you would need is a 1.4 amp power supply, regardless of voltage. You can run multiple power supplies for smaller arrays, but overall you are still going to need at least 1.4 amps for the 70 LEDs you spoke of (don't forget anything else that may use power too like fans and such).

3.) How closely would you space the LED's?

I spaced mine about 1/4 inch apart. You can pretty much space them as close as you want, but just remember that wiring them together becomes more difficult the closer they are.

[chucklez]

ya know, I have been searching for a couple of hours now for a chart showing the light spectrum of the sun, and a chart showing the same for a LED. This is so I can compare the 2. Any ideas where I can find one?

[gcrowptc]

have read all 25 pages in 1 sitting wow....am a firm beliver leds are the future of lighting, have several moonlighting setups with leds and swear by them

[LakeEd]

Originally posted by chucklez
ya know, I have been searching for a couple of hours now for a chart showing the light spectrum of the sun, and a chart showing the same for a LED. This is so I can compare the 2. Any ideas where I can find one?

Chucklez,

What you need to remember, we aren't attempting to simulate the "sun" per-say... but the spectrum of light UNDER 20 to 30' of water, for our tanks. The water filters out many spectrums of light quickly.

Ed

[chucklez]

true. The reason I was asking for a graph is see how similar LED and sunlight is.

I do have 70 21000mcd ultr bright LEDs on the way, and when I configure them, I will take a LUX reading in 2 foot of water. I hope to be able to determine if it is worth outfitting a large tank in LEDs versus MH.

[Worldwithin]

Well, I guess the best thing to try is take a bucket or small tank and fill it with 2 feet of water, place it out in the sun and at the sun's highest point that you can figgure, take a par reading in your tank. That would give you an idea as to what your water is filtering out from the sun. Now granted, it probably will not be as intense as that of the tropics, but it will give you something to start with.

Once you have those readings, you can compare them to what you currently have with a MH setup and then the LED setup.

[drseuss620]

I don't know if this has been mentioned yet but one of my engineering buddies tells me you can double and even triple the output of an LED without shortening its life.

LED's generally burn out when the capacity for heat dissipation drops below the heat output... (Or so my buddy says) Anyway, the way you double and tripple the output is to pulse the power input with a "square wave pulse" on a 50% duty cycle.

The way I understand it is something like this... If you took a picture of an LED for 1 second it would be continuously on at 100%. If you put it on a square wave pulse at 3 times the output it would be on for half a second at 3 times as bright then off for half a second. Now scale the time down so that it is running at 40mHz or something like that. The LED would be turning off and on so fast that you wouldn't even notice the pulse.

Maybe this will help by increasing the output while still maintaining the long life of the LED.

If that original reading of 600 Lumens was correct when wired in parallel then wouldnt you be getting 1800 lumens at 3 times the output?

PLEASE NOTE: I am not an engineer and I am trying to translate engineer speak into english. :P You get the idea of what I am trying to say though...

Aparently a Square Wave Pulse device can be made/purchased fairly cheap.

Just an idea... will it help? I hope so.

[robwsup]

Three times as bright for half the duration, would equal a a 50% increase in light output, not 200%-300%.

1/2*3(L)=1.5L

Sure it's brighter when it is on, but when it is pulsed off, it puts out 0% as much light.

[bzzbee2]

This has been discussed before. this way of powering LED's is known as Pulse Modulation. And it can work. The reason is that when it pulses on and off, the LED dosent go completely off there is stored energy in the lines and capiciters, which will give the LED's enough power to stay on, however not as intense. so its not putting out ther 0% light. when viewing with a high speed camera you can see the pulsing, from bright to not so bright, however it does not go off.

I did some research on this a few months ago, the problem that i was having a hard time getting around was the cost of the modulator, or auctually finding something that would modulate the pulses to the frequency wanted.

[sandisct]

bump

[chucklez]

I guess this thread is all bumped out.

Actually, I am in the process of creating my own LED array.

This array will have:
70 21000 Mcd White LEDs
40 7850 Mcd Blue LEDs

I am connecting it to a control board I have here at work to turn on certain sets of lights, at certain times.

I am going to test it on a small tank for now, and try to grow a peice of coral to see if it works ok.

Once it is completed, I will post pics.

[Worldwithin]

Just what exactly does "bump" mean?? I see it often and don't really get it.

[tam]

bump, is a post just to bring the thread back to the top[bump it to the top], or youll see TTT which means "to the top!"

[hydro]

HI
I think the reason this thread died out is like many I thouth that mabey there was a new light source that was 1. cheaper 2. less heat 3. smaller. But the prevailing thought on this thread has been thanged to having to buy the expensive lights and run heat sinks too them cool witch pretty much killed all three of the benifits. In a nut shell they have become hallides large hot and expensive.
Joe

[johnny1]

I have no need nor desire to run MH, but I do like the shimmer effect it produces. I think the best way to get that look is from using LEDs with VHO. I think I will build somthing to try to achieve this in the future.

[bleach]

Your post is in violation of the terms and conditions of use of this web site and has been edited. Further violations will result in revocation of your posting privileges.