Custom Power Solutions

For many years, before batteries were mass produced, electrical experimenters had to make their own batteries and many concoctions were tried. You "can" try this at home yourself with materials commonly found around the house.

Recipe for Making a DIY Battery

Ingredients

• 1 Lemon or lime
• 1 Galvanised roofing nail or galvanised screw
• 1 Piece of heavy copper wire (Mains cable without the insulation) or a shiny copper coin.

Equipment needed

• 1 Voltmeter

Checking the Ingredients (Optional)

You could try the old fashioned "Tongue Test" (First make sure the parts are clean. See 2 below)

As with wine tasting: Taste - Don't swallow.

(Note: This is an experiment in electronics, not electric cooking. We recommend that you do not eat the fruit used in your battery)

Preparation

1. Squeeze the lemon gently without breaking the peel to release the juices inside.
2. Thoroughly clean the nail and the copper wire until they are bright. Use steel wool if necessary and rinse well in water.
3. Insert the nail and the copper wire deeply into two separate points on the lemon taking care that the wire does not touch the nail.
4. Check the potential between your two improvised skewers with the voltmeter.

Brewing time

Ready immediately

Serves up

About half a Volt

Hungry for Power?

Don't expect to start your car with this battery - The internal resistance is rather high.

By connecting 3 or 4 batteries in series however you should be able to light up an LED (Light Emitting Diode) or a small flashlight.

Flavours

The lemon may be replaced by other fruits or vegetables. You could try an Electric Potato for starters. The electric effect is the same.

Using a paper clip instead of the nail reduces the output to one third of a Volt.

If you can't find a galvanised nail, an alternative (and better) source of zinc is to cut a strip from the case of an old flashlight zinc carbon battery (D Cell).

Chef's notes

The lemon acts as a battery case holding the lemon juice (citric acid) which acts as the electrolyte. The copper Penny is the Positive electrode and the zinc galvanised coating on the Nail is the Negative electrode.

A series connection is a chain of cells, the positive electrode of each cell connected to the negative electrode of the next cell, to form a battery of higher voltage.

Alternatives

A passable replica of Volta's pile can be constructed from a stack of alternately placed copper and nickel coins separated by discs cut from a paper towel and soaked in lemon juice or vinegar.
( Make sure the surfaces of the coins are not oxidised)

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For an explanation of how batteries work, see Battery Chemistries.