How Your Car Battery Works

A car battery can weigh 10.5kg to 30kg due to the lead plates within the battery cells. A lead-acid battery is made up of six smaller batteries lined up in a row, as shown on the diagram, each cell is able to produce around 2 volts of energy, thus most batteries are 12 volts. The plates are submerged into sulphuric acid, which causes a chemical reaction releasing electrons. These electrons flow through the conductors producing electricity. This chemical reaction can be reversed, which is what enables you to jumpstart your car when necessary, so the battery can be used again!

Charging Your Car Battery

The charging system from your alternator should charge between 13 to 14 volts. This is because when you put your lights or anything electrical on the car, you take 12 volts out of the battery and need 1 to 2 volts to go back in. If you haven’t got the correct amount of voltage going back into the battery, all of the power will come out of the battery which will drain it.

Your car battery can go flat for various reasons:

• Extreme weather conditions

A car battery is 35% weaker at 32 degrees and 60% at 0 degrees, so it’s good to be aware in the winter months!

• Frequent short journeys

These do not allow the battery to recharge fully

• Time

The average car battery dies after 3-5 years. Although leaving an interior light on overnight or electronic devices will drain the battery more quickly

• Corrosion

Battery acid is corrosive, therefore the connections may corrode. If this happens then the alternator won’t be able to recharge your battery properly. Corrosion can appear as white powder or green growth on the battery terminals.

How to charge your car battery:

First, check which kind of battery you have.

1. Check the lead terminals

If they look dirty or corroded, they will need to be cleaned, which can be done with a wire brush.

2. Disconnect the battery

To do this disconnect the negative lead first and reconnect it last in order to avoid getting an electric shock when you touch the positive terminal. To disconnect the terminals from the battery, loosen the bolt on the side.

3. Connect the charger
Find a flat surface to charge the battery on and make sure it is kept as far away from the charger as possible. Connect the battery charger cables to the battery by matching the positives and negatives. Once secured, plug the charger in.

4. Turn the charger on
Turn on the charger and check whether you will need to turn it off manually once it has finished charging.

Many chargers will be low speed at 2-3amps, used to charge a car overnight. However high-speed charging is generally 6-10amps. A fully charged battery should read 12.6 volts or higher.

Written by Amber Callender