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Homemade Supercapacitor Capacitance test -- Help Please

  1. Mar 1, 2015 #1
    Hi all,
    My friend and I have created a homemade supercapacitor. It can power a LED light and small alarm clock. We charged it up to 1.5 Volts. I was wondering if anyone knew how to find the exact capacitance in Farads, any help will be appreciated. I have added the steps that we have taken in making it below.

    1. Make around 4 current collectors by cutting the iron mesh into rectangles. Add a single line, approximately 1-2 inches, of iron mesh at the end.
    2. Flatten the current collectors with the hammer, if needed.

    3. Unravel string of fine iron from the scouring pad and wrap them around each of the current collectors.

    4. Grind some of the activated carbon using the coffee grinder.

    5. On one of the metal disks, sprinkle the ground activated carbon. Place one current collector on the carbon, and spread epoxy glue generously. Put spoonfuls of activated carbon on top, making sure that no epoxy glue is showing.

    6. After placing the second metal disk on top of the current collector, use the pliers to apply pressure between the disks.

    7. Gently remove the discs and place the collectors in a separate area.

    8. Add more of the epoxy glue and carbon to cover more than ¾ of the surface if needed.

    9. If using wires, strip the insulator from the ends of the wires with wire cutters, revealing the copper conductor.

    10. Twist the ends of the wires on each of the current collector tails, red wires for positive plates and black wires for negative plates.

    11. Cut pieces of shade cloth slightly larger than each current collector.
    11. Place two layers of shade cloth on the bottom, and put one current collector on top. Repeat this step until all of the current collectors are in one stack. Position them in a fashion so that the negative and positive current collectors alternate, and the tails are on the opposite side depending on the terminal (negative or positive).

    12.Carefully place the stack of current collectors in the bottle. Ensure that the metal plates are not touching each other.
    13.Pour the Drano Crystals and water solution (10% NaOH) in, filling ⅞ of the container.
    14.Double check the shade cloths to see if they are still standing.
    15.Twist the black wires together at the top (copper part), then do the same for the red wires. Drill holes in the lid where the wires are.
    16.Put the lid on the container and gently pull the wires out of the holes. Stand them up straight.
    17.Using the multimeter, check the resistance between the terminals. It must be above 0
    18. Attach the Variable DC Power Supply to the supercapacitor. The first charge will take overnight or 10 hours, but after it will take a much shorter time.

  2. jcsd
  3. Mar 1, 2015 #2


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    Staff: Mentor

    Hi Bleackley. http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif [Broken]

    Sounds like some interesting home experimentation you've been doing there. For how many hours does it keep a LED glowing?

    Perhaps you could provide a link to the article where you saw these instructions?
    Last edited by a moderator: May 7, 2017
  4. Mar 3, 2015 #3


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    Gold Member

    I suggest you charge the capacitor fully and then discharge it into a resistor of, say, 100 ohms. Measure the time taken for the voltage to fall to 63% of the fully charged figure. Then RC = T, so you can find C.
    Last edited by a moderator: Mar 3, 2015
  5. Aug 17, 2015 #4
    I'm trying to make a supercapacitor as you made, but unfortunately, I don't know what kind of epoxy glue I should use. could you please help me ?
    [mentor note: email address removed]
    thank you
    Last edited by a moderator: Aug 17, 2015
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