How to check a car’s battery
Without a healthy battery, your car is little more than an expensive paperweight — here’s how you can make sure it stays in tip-top condition
A car battery may be a small piece of the puzzle under the bonnet, but it’s up there with the most crucial components.
Without a properly functioning battery, the car will struggle, or even fail, to start. While they can stay in good health for a long time, they will eventually deteriorate — meaning it’s vital to keep an eye on the unit and knowing when to replace it.
How does a car battery work?
A car battery functions in a pretty similar way to any conventional cell — it’s wired up to provide power to electronic components.
In this case, the electronic component is the starter motor, which gets the car’s engine running. The engine then turns the alternator, which takes the load off the battery by powering most of the vehicle’s internal components — while also recharging the battery itself.
Why do they go flat?
Just like any battery, the one found in your car has a limited energy capacity — which will eventually run out.
If the battery is left to provide power to the car for too long without any energy return from the engine’s alternator, it will eventually go flat. Its ability to hold charge also diminishes over time — meaning it could be time for a new one if it goes flat often.
How can I check my car’s battery?
Unlike say your fuel levels and fluid temperatures, which are easy to see on a car’s instrument cluster, not many machines show a reading of the battery’s condition — so you’ll have to invest in a bit of extra equipment.
A multimeter will be able to tell you the DC voltage of the battery. As a general rule, a car battery should read no lower than 12.6V to be considered in good health — anything lower and it might be time to switch it out.
Which battery should I put in my car?
Batteries vary between cars, so don’t expect a one-rule-for-all here.
The easiest solution would be to head to an online retailer, with many offering tools to find the right battery for your car by simply entering the registration of your car.
Alternatively, you could look for an identical battery to the existing unit by its serial number.
Can I change a car battery myself?
Although we’d always recommend seeking specialist help before undertaking any mechanical task yourself, changing a battery is a fairly simple task.
Park the car on a level surface and secure it with the handbrake first, before opening the bonnet. Once the battery has been located, disconnect the negative terminal first before then unclipping the positive. The battery should then be fairly easy to lift out, ready for a new unit to be placed in.
How should I dispose of an old battery?
By law, car batteries must not be disposed alongside regular household waste.
Fortunately, many recycling centres have dedicated facilities for car batteries. Take the old unit to your nearest centre, where it can be safely and legally disposed.
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