Author Topic: Ultio1's 12 V LED lighting  (Read 3565 times)

Offline Ultio1

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Ultio1's 12 V LED lighting
« on: December 28, 2008, 12:36:18 PM »
Standard safety disclaimer. I am not a certified anything. I make no claim as to the safety of this device or its use.  However I will state that it is my belief that it is safe. I am aware that my soldering skills are marginal at best so please be nice.

I wanted a light for my shed in the event of grid failure. I mean if the SHTF there will be plenty of work to be done right? This solution is a little on the Mad Max end of the spectrum but it is so efficient that I feel that it may be useful. You probably wont be working on your masterpiece or doing any recreational reading with it but it provides enough light to work or read if necessary. I have an existing prototype already in place that has been running more than a year now with no problems. I am constructing an additional light with 5 LEDs (because thats how many I have on hand) for the purpose of this DIY post. This will work without the resistors but it will damage your LEDs dramatically shortening their life.

existing 3 LED array consisting of 3 5mm white LEDs, a 120 ohm resistor, a 2 inch length of 1 inch PVC and the cap from a plastic water bottle.

List of parts for 5 LED array:

5 White 5 mm LEDS from radio Shack  they cost about $1 or $1.50 each there. Can be had cheaper online if you buy in bulk.
1 120 ohm resistor aprox .$02 (I bought a bulk bag of 500 assorted resistors at radio shack for $7 )
1 270 ohm resistor
1 switch
small section of pvc pipe for housing.
what ever length of wire is appropriate for your use/application
electrical tape

Polarity (+/-) is important concerning LEDs. If you look at your LEDs you will see that one lead is longer that the other, the longer one is the positive lead.

Polarity is not important regarding resistors for this project.The resistors have different values because of the odd number of LEDs.

    *  each 120 ohm resistor dissipates 48 mW
    * I am using 1/4W resistors
    * the 270 ohm resistor dissipates 108 mW
    * together, all resistors dissipate 156 mW
    * together, the diodes dissipate 330 mW
    * total power dissipated by the array is 486 mW
    * the array draws current of 40 mA from the source.

Lets start by soldering the 3 led portion of the array first. Find the long lead (=) on one LED and solder it to the short lead (-) of another LED being careful not to heat the LED leads to much.

clipping the excess leads below your solder.

Then solder the unsoldered lead to the positive lead of the third LED.

Dont forget to clip the leads under where you have soldered them. Now do the same thing for the remaining two LEDS. So you end up with 3 LEDs soldered together and then 2 leds Soldered together.

Next solder the 120ohm resistor to negative side of your 3 LED array and then the 270 to the negative side of the 2 LED arrray. You should end up with this.

Then solder the two positive LED leads together and then the two resistor leads as well. Should look something like this.

I dont have the other parts on hand to finish it today but from here you simply insert it into its housing and connect the resistor end leads to the negative or ground and the LED lead end to the positive. Insert a switch in the loop and Viola! super high efficiency, low cost lighting. I will take some pics of the shed in the dark with the LEDs running in the dark tonight to post as well.

I run my little light on a small 2 battery array consisting of 2 550 Amp Hour 12 v deep cycle batteries (bought at wal-mart for about $70 each) for a total of 1100 amp hours output. This new 5 LED array with a 40 mA draw will run from those batteries for 27,500 hours (1145 days, or 3.1 years)  before needing a charge. I use a solar trickle charger to keep a fresh charge. 40 mA = .04 amps

I plan to make several more of these and see what sort of output I can get. I am hoping to light my work bench enough to work well into the night if need be.   Updates will be posted as soon as the it gets dark and  as materials become available

More photos here at my photo bucket.
« Last Edit: December 30, 2008, 11:55:45 PM by Trioxin »

Offline The Wilderness

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Re: Ultio1's 12 V LED lighting
« Reply #1 on: December 28, 2008, 01:26:11 PM »
Nice job Ultio1! +1 Good description and pictures. Very complete and informative. This could have a number of uses. I really liked the battery life statistics you figured out and included in your post.

I would love to see more of these DIY threads from forum members.

The Wilderness

Offline firetoad

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Re: Ultio1's 12 V LED lighting
« Reply #2 on: December 28, 2008, 02:08:17 PM »
Polarity (+/-) is important concerning LEDs.

Only if you want light!   ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D

All joking aside, very nice post Utilio1! 

Just to add a little background information for everyone, here are some links on basic LED circuitry.  Using the information located at the linked sites, you can modify the great information from Utilio1 above and make just about anything you would want out of LED's and batteries!

Offline DeltaEchoVictor

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Re: Ultio1's 12 V LED lighting
« Reply #3 on: December 28, 2008, 02:59:50 PM »
+1 pal.

Marginal soldering skills not withstanding ;D, damn fine job & cool how to.  Now I just have to figure out what all that meant. :D

Offline Ultio1

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Re: Ultio1's 12 V LED lighting
« Reply #4 on: December 28, 2008, 06:36:30 PM »
The shack with no light.

The shack with the 3 LED array on. I wont be growing anything under it but I could repair something in an emergency. I think six of these could illuminate an area pretty well.

« Last Edit: December 28, 2008, 06:40:10 PM by Ultio1 »