How To Build A Battery With Pennies

This is a fun little DIY project that can serve you in emergency situations to power up small electronic devices like LED’s, or calculators.  It’s also a good one to teach the kids, and a lot of fun to learn.  What we will doing is building a working battery out of pennies by using everyday household items.

And what’s cool about these penny batteries is that they’re actually rechargeable; which can be great to have in dire situations.  Below you will learn the simplest way to do all of this with step-by-step video and image instructions.  Enjoy!

We were amazed when Grant Thompson told us that the battery he created in this video to power the LED lasted for 2 1/2 weeks. Amazing!

So here’s all the steps in the process, what you will need, and other potential uses, such as increasing amperage, and some easy ways recharge them.  Read below for more details:

What I Need To Make Penny BatteryWhat You Will Need?

Lets make some penny battery cells.  You can do 3-stacks which should produce over 2 volts, and be enough to power a calculator; or 10-stacks which should produce around 6 Volts, and is enough to power an LED for over 2 weeks.  Same materials are needed whatever you choose.

- Pennies
– Cardboard
– Zinc Washers
– Electrical Tape
– White Vinegar
– Multi-Meter(optional)
– LED’s or Small Calculator – (To Test With)

These items are not set in stone.  For example; instead of cardboard, you can use filter paper, or paper towels.  instead of zinc washers, you can just sand down one side of the penny.  Instead of white vinegar, you can use lemon juice, or salt water.

Prep The PenniesStep #1 – Prep Pennies or Use Zinc Washers

We need a positive terminal which the copper penny will serve as, and we need zinc to serve as a negative terminal.

We have two options to get zinc.  We can either grind down one side of the pennies with 100 grit sandpaper or orbital sander to expose the zinc.  Make sure these  pennies are dated after 1983, as these are made of 97.5% zinc and plated with a thin copper coating.

Or we can just use zinc washers.  Using zinc washers will end up being a lot easier.  And If using zinc washers, use pennies dated before 1982, as these are made up of 95% copper.

You probably have some zinc washers in your toolkit.  If not, zinc washers are available from most hardware stores.  A package of 30 usually costs less than $2.

if you decide to grind the pennies down with an orbital sander, you may have to use adhesive remover such as goo gone to clean them up.

Prep The CardboardStep #2 – Prep The Cardboard

Line up pennies on top of your sheet of cardboard, and draw a circle around each penny.  It is best if we cut out circles and not squares, as we don’t want pieces hanging off the side as this can short-circuit the battery.

Once you cut out one circle for each penny, drop them in a cup of the acidic solution which will serve as an electrolyte.  You can use vinegar, or lemon juice.

Let soak for a minimum of 3 minutes to ensure it is saturated.  Make sure you swoosh around with your finger.

While soaking, start to prepare your battery cell by first laying down a piece of aluminum foil on the table, which will serve as a terminal conductor for testing purposes.

Build Your Battery Stack

Step #3 – Start Building Battery Cell

If using Zinc washers, lay down on top of aluminum foil in this order: zinc washer on bottom, cardboard in the middle, and the penny on top.  This makes up one cell.  Continue with this same arrangement until you complete your stack.

Make sure you blot dry the cardboard pieces prior to stacking them on the tower.  You don’t want liquid dripping all down the tower.

If you have a multimeter, you can test the voltage reading and/or current draw(amps) throughout the stacking process.

If using sanded down pennies, lay down on top of aluminum foil in this order: Penny copper side down/zinc side up, cardboard in middle.  This makes up one cell.

Remember, although you are using one penny, there are 2 terminals.  The sanded down zinc side is the negative terminal, and the copper side is the positive terminal.

Test and set up to electronic deviceStep #4 – Test And Setup To Device

Once you finished building your battery tower, you can first test the amps and voltage reading with a multimeter.

You can start hooking up any small electrical devices that you think can run on around 6 volts, as that’s what you should be getting from a stack of ten.  If you built a stack of 5, you should be generating around 3 volts.  If your getting more, then you did well.

You can set it up with 1 or 2 LED’s to see how long it lasts for.  Grant set up 1 LED, and his was bright for 2.5 weeks before finally fizzling out.  That’s pretty impressive.

If attaching other devices, just open up device, and pop out the 2 lead wires that will connect to the bottom and top terminals of battery cell.  And then you can just tape the battery stack to the back of device.  Remember, copper is positive, and zinc is negative.

IMPORTANT: Make sure that the battery cell is taped up well with electrical tape, and that it’s air-tight to prevent the wet cardboard from drying out too quickly.  These are wet-cell batteries, so the longer the cardboard stays wet,  the longer the battery will last.

These Little Babies Are Easily Rechargeable

The best thing about these little babies is all the hard work is done.  You already sanded the pennies down, or bought all the washers.  And you already cut out the cardboard.

All you have to do is peel open the electrical tape, toss the cardboard in your Lemon juice or vinegar for 3 minutes, and swoosh around with finger.  Rebuild back into battery cell.  tape back up with new electrical tape.  your good to go.

There’s More Potential…

We showed you how to build penny batteries up to increase its voltage, but you can also build them side to side(parallel to each other) to increase its amperage.  This will actually double the current by adding the same stack of batteries in parallel to it’s previous stack.  This is the same concept hybrid/electric cars use.  This video explains exactly how to do that, starting at 5:55 seconds into the video.

Use this concept in conjunction with what you learned, and scale it up.  Try different methods.  Split-test.  Play around with it — and maybe start charging bigger devices like flashlights, lamps, or even cell phones.

Then come back here and post your results.  We’d love to hear success stories.  And we will do the same, so don’t  forget to bookmark our page, or subscribe to our feed.  Also see some of our other cool DIY Emergency projects.

The Science Behind Batteries?

And this video is excellent in describing in layman’s terms the difference between Current and Voltage.  And this article goes into more technical details of the chemistry behind it all.

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