Penny Batteries Part II: A Wee Success

Wait! Is the bulb lighting? I can't tell!
Is the bulb lighting? Hard to tell. This shows a four-cell battery using pennies and zinc washers.

posted by Beret

Remember my penny battery debacle?

I decided to hunker back down in my laboratory (aka, basement) to see if I could get the darn thing to finally work. I approached the project with a new tool:  very, very low expectations. I am beginning to think that may be the secret to success in a variety of situations.     

As you may recall, I had tried to make a penny battery using two different methods:  by sanding pennies (minted 1982 or later) down to the zinc on one side, or by using zinc washers from the hardware store.

The good news is:  I managed to produce electrical current using both methods. The bad news:  it was a little anti-climatic after my epic struggle. Chances are, things would have gone more smoothly had I not been hindered by insomnia and a terrible cold.

For the first scenario, I stacked the pennies on a piece of aluminum foil like this:

1. Foil 2. sanded penny copper-side down, zinc-side up

1. Aluminum foil with one sanded penny–copper-side down, zinc-side up.

2. A small piece of vinegar-soaked cardboard.

These first two layers comprise one cell of the battery, but we will need more cells to generate enough power to do much of anything. Continue like this:

3. Another sanded penny, copper-side down.

4. Another piece of vinegar-soaked cardboard.

Repeat the stacking order until you have at least three or four cells, and end with a penny, zinc-side up.

Look, look, look! I used a voltmeter to see if the battery generated current. The positive end is touching the zinc, the negative the aluminum foil. It worked!
Look, look, look! I used a voltmeter to see if the battery generated current. The positive (red) end is touching the zinc, the negative (black) end touches the aluminum foil. It worked! 2.26 volts from my four cells!

As you might see in the pictures, I never got absolutely every last iota of copper off of one side of the penny. It still worked; that was a pleasant surprise.

I couldn’t get much action from an LED bulb–just a dim glow–but I did hook the battery to a super cheap digital clock, and got it to start ticking!

penny clock

Next, I re-created a battery with intact, un-sanded pennies sandwiched between zinc washers and vinegar-soaked cardboard. FYI:  I found that #10 washers were a great size, and cost me a whopping 3 cents each.

I started by putting a small zinc washer on a piece of aluminum foil:

washer 1

Then I stacked cells like I did for the other battery, except there are three layers:  washer,  vinegar-soaked cardboard, then penny. Repeat ad nauseum, but be sure to end with a penny on top.

Here's the stacking order for a penny battery using zinc washers.

With just three cells, I got the clock to start working.

washers clockAnd, if you look veeeeeery carefully, you can see that I got the bulb to (barely) glow with four cells:

washer lightAnd that’s it. If I had done this project before the lemon batteries, it might have impressed me a bit more. Or perhaps the problem is that now I associate making penny batteries with a “terrible, horrible, no-good, very bad day.” In any event, it’s cheap, easy (if you skip the sanding and use the right washers), and dad-gummit, it works. Enjoy.

Author: Beret Olsen

Beret Olsen is a writer, teacher, and photo editor for 100 Word Story. She loves toast, the Oxford comma, and all your comments and questions.

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