How to Make a Fruit Battery

Can fruit really be used to make a battery? Would it work with all fruits? Well, let’s get some things together and see what we know and what we can learn.

Batteries are gadgets that are designed to store chemical energy.  When the energy is needed it is converted to electrical energy.

*2 inch copper nail
*2 inch galvanized zinc nail
*gator clips
*small colored LED light

1. Prepare the fruit.
It is important to have the juices flowing in the fruit.  It is also essential that the skin or peel of the fruit stay in tack.  Take the fruit and gently roll it on the table with some pressure.  Do it until you can feel a little give in the consistency of the fruit.

2. Carefully take the nails and push them into the fruit.  Make certain that they do not touch each other and they do not go all the way through the fruit.

3. Remove the insulation around the bulbs wires. Now you can see the wires underneath.  Tear away enough insulation so the wires can be wrapped around the nails.

4. Now it is time to attach the wires.  Take one of the exposed wires and wrap it around the galvanized zine nail. Use a gator clip to secure it.

5. Wrap the other end of the wire around the copper nail.

6. As soon as the second wire is attached to the copper nail, there should be light.

Clearly now we can see it works with grapefruit.  And that leads to other questions and experiments.  A watermelon is huge and is very juicy.  Would it work?  If it did work could it power a string of lights because of its size?

If two of each kind of nails light up one light bulb, can four nails be put in the grapefruit to light another bulb?

Is it only citrus fruits that work? Peaches are fairly juicy, maybe they would work.   Perhaps an apple would be worth a try.  

Maybe a little research to go along with building the fruit battery would be a good idea. Is it the acidity of the fruit that makes the difference?  If so wouldn’t the tomato be the best choice?

Here are the basics to understand the process. Zinc is an active metal that reacts to the acid in the fruit juice.  The fruit juice has positively charged ions.  There is a transfer of electrons that takes place between the acids in the fruit juice and the zinc nail.  The nails act like the separate posts on a battery.  One is negative and one is positive.  As the electron travel from the positive pole to the negative pole.  They move through the conductor (light bulb) and generate enough electricity to light up the bulb.

Make a little fun science today.