Make a Battery out of Pennies in 6 Simple Steps

Source and original idea via Instructables.

Nothing in life is free. When everything costs something, wouldn’t it be nice to have something for free? If you have some spare change lying around, you could make use of it. While pennies aren’t worth much these days, they can still be useful. And in this tutorial, we will show you how.

Step 1: Start by watching the video

You can find the video here.

The video shows how a handful of pennies can provide enough energy to make a makeshift battery and drive calculators and other smaller devices like LEDs.

Step 2: Choose your pennies wisely

Pennies that are newer than 1982 will work great for this project. Newer pennies are around 98% zinc. Check out more information regarding US pennies to see zinc and copper ratios here.


From user u/EkriirkE on Reddit: So I see you mentioning only newer than 1982 pennies a lot, but this is only relevant if you don’t have zinc and need to file one down. 1982 and older are actually better for being pure copper since newer ones will erode the plating to the zinc and stop working sooner.

Step 3: How to power a calculator with 3 pennies

For this project, you will need:

  1. A small calculator
  2. A piece of cardboard
  3. Saltwater or vinegar
  4. Paper towel
  5. 3 pennies newer than 1982
  6. Zinc washers
  7. Electrical tape
  8. Aluminium foil

Once you have the calculator, remove its battery and save it for some other project.

Next, pull out the positive and negative leads and attach them to the terminals. You can use tape to hold them in place.

To make the penny battery, start with the cardboard.

Cut the cardboard in a circular pattern in a way that its edges are slightly bigger than the pennies. You will need three pieces of cardboard for three pennies.

Let the cardboards soak in vinegar or saltwater for 2 minutes.

Place the aluminium foil on the table and place a zinc washer on it. Next, take the cardboard and dry it with a towel. After it’s dried enough, position it on top of the washer. The cooper side of the penny will go on top of the cardboard. That’s it. The structure for the battery is done.

Note that a battery cell has a copper top and zing bottom and is separated by a material soaked in an electrolyte such as vinegar.

The copper top of the penny is positive while the zinc bottom is negative.

Photo Credit: Instructables.

To use the pennies in the right way, you need to measure how much power a certain device may require. For example, a single cell holds around 0.6 volts (700mA) energy. A small calculator needs at least 1.5 Volts. So you need to use 3 pennies to power a small calculator. The 3 pennies would require 3 separate pieces of cardboard and 3 separate washers.

Use wires at the top and bottom and add some electrical tape to hold the apparatus together. You don’t need the aluminium foil, so you can discard it after the pennies are nicely wrapped in tape.

Interesting fact: The DIY penny battery works the same way as the original battery introduced by Alessandro Volta in the 1800s. The first battery came to be known as Voltaic Pile.

Step 4: Test it out

Connect the positive and negative wires to the battery leads and press “on”. You will see that your small calculator works perfectly!

If your DIY penny battery stops working, re-soak the pieces of cardboard in vinegar a little bit more and try again. You will notice that the calculator will come back to life.

Step 5: Create a large wet-cell battery

Photo Credit: Instructables.

If you don’t have zinc washers, you can try the following method to create a large battery.

For this, use 10 pennies. Here again, get pennies that are newer than 1982. You will need 100-grit sandpaper to sand one side of the pennies. Sand the side until you see the zinc surface.

Next, cut the cardboard for the 10 pennies just like you did earlier for the 3 pennies. Soak the cardboard pieces into vinegar. After drying the cardboard pieces, stack them with the pennies as shown in the figure above.

Notice that the corners of the cardboard boxes are sharp and not evenly rounded. You don’t need to round the edges, just make sure they don’t touch. If the cardboard pieces come in contact, it will reduce the performance of that section, and it will in turn reduce overall battery performance.

Remember that the zinc side will go on top and the copper will go on the bottom. With this method, zinc is positive and copper negative.

The ten pennies will give you around 6 volts of power, enough to power a small LED. Use the LED light by pressing the light’s long head (positive) on top of the battery, and the short end (negative) on the aluminium base.

Photo Credit: Instructables.

Step 6: Wrap it all up

Wrap the 10-penny apparatus to the LED with electrical tape and set it somewhere. Now you can wait and see how long the light lasts.

For more information about the legality of these experiments click here. The federal law allows for certain exceptions that include the use of metal content of the coins for educational, novelty, amusement, and other similar purposes that don’t seek to make a profit.

Source via Instructables.

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