How Long Do Car Batteries Last?

Generally, a car battery in a petrol or diesel vehicle has a lifespan of three to five years. In electric cars, batteries last a lot longer — around 8 to 15 years. 

Petrol and diesel cars use lead-acid batteries. Most electric cars use lithium-ion batteries, which are more energy-efficient and slower to degrade. That said, a car’s battery lifespan is affected by several factors, such as how regularly you drive the car, how cold the climate is, and whether you practice proactive battery maintenance.

Inevitably, though, your car battery will need replacing at some point.

Before your car battery fully expires, it will give you some clues that it’s nearing the end of its lifespan. To avoid the headache of dealing with a completely dead battery, look out for the following signs that your battery needs replacing.

Dashboard warning lights

If the battery warning light on your dashboard illuminates when you start and/or drive your car, it’s a sure sign that there’s an issue with your battery. It could point to any number of problems, from corroded terminals or damaged cables to a malfunctioning alternator belt. A reputable mechanic can diagnose the issue.

Ignition problems

Your car’s battery and your car’s engine work together to start your car. So, if your battery is failing, it won’t be able to deliver sufficient electrical energy to the engine. This causes your vehicle to crank slowly or, in some cases, fail to start at all.

A professional mechanic can diagnose if a weak or failing battery is causing your ignition problems by testing your car battery’s strength and charge. 

Dimming headlights and electrical issues

Your car’s battery powers numerous electronic components — the headlights, radio, air conditioning, heating, and USB ports, for example.

Dimming headlights are a common symptom of a failing car battery. It’s crucial that you take your car to a local garage straight away, as dim headlights pose a serious safety risk to yourself and others. 

You might also notice that your air conditioning or heaters are performing poorly, or that your USB ports aren’t charging your devices. These are glaring signs of a battery that’s struggling to generate enough power. 

Frequent jump-starts needed

Car batteries become less able to hold a charge as they age. If you find yourself jump-starting your car more frequently than usual, your battery is probably on its way out.

Remember, jump-starting is only a temporary fix. Do it too often, and you risk causing jump-starting damage to critical electrical components. 

Swollen battery case or visible damage

Extreme heat, overcharging at high voltages, and degrading components can cause car batteries to swell. The excessive buildup of heat and gas in the battery case can lead to a rupture, potentially damaging other components and/or causing a fire. 

So, if you spot any swelling, cracks, or discharge leaking from the case, immediately contact a mechanic for an urgent battery replacement.

The secret to extending your car battery's life is in practising regular car maintenance and adopting optimal driving habits. Let’s explore some steps you can take to increase the longevity of your car battery.

Regularly driving your car

To preserve your battery's lifespan, you don’t want its charge to drop below 50%. However, your car’s alternator only recharges the battery while the engine is running. When the engine is switched off, the battery isn’t charging, but it’s still supplying power to electrical components like your dashboard clock and anti-theft systems. 

This means that when you leave your car idle for weeks or months, you risk returning to a drained battery.
Regularly driving your car keeps your battery topped up. A drive of around 30 minutes once a week should be sufficient.

Avoid short trips

Frequent short journeys also degrade your car battery’s health and shorten its lifespan. By constantly stopping and starting your car, you never give the battery enough time to fully recharge, putting increased strain on your car every time you start it. 

To combat this issue, avoid taking regular short trips. Take your car for a 20-30 minute drive at least once a week to ensure that your battery stays topped up and healthy.

Switch off lights and electrics when parked

Leaving electrical components switched on when your engine is parked can cause what’s known as a “parasitic draw” — an electrical current drain that depletes battery power while your engine is off.

Accidentally leaving your exterior lights on is a common culprit, so be sure to switch your headlights off once you’ve parked. Other electrical components, such as heated seats, interior lights, or GPS devices, should also be turned off to extend battery life.

Be aware that a parasitic draw can also occur due to a malfunctioning electrical component. A stuck relay, short circuit, or wiring issue, for example, can prevent electrics from going to “sleep”, meaning that they continue to draw power and drain your battery. A multimeter can help you test for parasitic draw.

Check for corrosion and keep terminals clean

Battery terminals are prone to corrosion — a blue or white coating that’s the product of a chemical reaction. While it’s completely normal, it can cause ignition problems and shorten your car battery’s lifespan if left for extended periods. 

So, regularly check your battery terminals and clean them with a bicarbonate soda and water mixture to keep corrosion at bay. To do this, you’ll need to remove the car battery (we’ll discuss how to do that in a minute).

Book regular servicing and battery health checks

Every 12 months, get your car serviced at a garage and/or book a battery health check with your local autocentre. During both services, your battery will be proactively assessed for signs of damage, swelling, corrosion, and other health issues.

The expert will be able to tell you how healthy your battery is, whether any components need repairing or replacing, and even offer tailored tips to help you extend your battery life further.