Stop-start systems might be good for fuel economy and the environment, but they help to give your battery a proper pasting too.
We’re only talking about a car’s 12V battery here. Hybrid cars and electric cars also have much larger and more powerful batteries that either assist an engine or power the car alone, but most do still have a 12V battery, though. Hybrid and electric car batteries are discussed further down this page.
How to check a your car battery’s health
As part of your routine maintenance checks, it’s good practice to keep an eye on your battery’s overall condition. There are a number of ways to carry out this inspection, and every process is easy to do. Here are some of the best ways to check your car battery’s condition, all of which should be carried out with the car switched off.
Built-in indicator
The vast majority of modern 12V batteries now have a built-in condition indicator to make checking it a very quick and easy task to do. Sometimes referred to as a ‘magic eye’, these indicators are a small circular symbol that sits within the top of the battery. If the indicator is green, the battery is in good health, if it’s black, you should only need to recharge. However, if it’s red, the battery is dead and it’s time to source a replacement.
Visual inspection
Take a close look at your battery and check for dirt or corrosion on the two terminals. This problem can disrupt the circuit, but it can potentially be fixed by simply disconnecting the battery and brushing away any grime. Also look out for any bulging in the battery’s casing, if you spot this, it could also be leaking acid so be very careful and do not touch it. This problem can be dangerous so the battery must be removed and correctly disposed of as soon as possible. If you’re unsure about safety, consult a professional.
Age
Time takes its toll on all car components and batteries are no exception. Your battery’s lifespan will be displayed on the label along with the manufacturing date. If your battery is past its prime, it’s time to replace it.
Voltmeter
Basic voltmeters can be picked up cheaply from most hardware stores and they’re fairly straightforward to use. First connect the positive wire to your battery’s positive terminal (this is usually red in colour) and then the negative wire to the earth terminal (this is usually black in colour). Once connected, the voltmeter should read around 12-12.7 volts. If the reading is any lower than this, your battery either needs a top-up or it’s struggling to hold a charge.
Changing a car battery: a step by step guide
1. Locate the car battery