Why Car Batteries Fail

A flat car battery can be a huge inconvenience, especially during those cold winter months. Dead batteries are the number one cause of breakdowns in the UK so it’s sensible to keep your battery in the best possible condition by regularly maintaining it.

Although batteries are subjected to wear and tear and will age and deteriorate naturally, understanding the most common reasons battery failure occurs can help you take better care of your battery, making it last longer.

Here we’ve listed the risks and main causes of battery failure as well as what you can do to prevent it to avoid the chance of unexpected breakdown.

Risks of Battery Failure

If your battery suddenly fails, you might find yourself stranded and needing roadside assistance. As well as disrupting your day, you might also be hit with an expensive recovery bill.

Another risk of a failing battery, is the potential to cause your vehicle to fail its MOT. If your battery is on its way out, your vehicle will not be considered safe and, again, might be costly to fix.

Common Reasons Batteries Fail:

Cold Weather

There’s a reason most people associate dead vehicle batteries with winter, and that’s because cold weather is the number one reason why batteries die. Cold temperatures affect the chemical process that produces and stores electricity, meaning the battery slows down and its ability to hold a charge is reduced.

Older, weaker batteries typically tend to be affected more by cold weather, so it is important to check the state of your battery in preparation for the colder months. It might also be worth charging your battery regularly during this time, especially if you’re only using the vehicle for short journeys.

Age of the Battery

The average car battery should typically last 3-5 years. Over time, the components inside the battery will become less effective, often causing a slow start. Whilst older batteries can cause headlights to dim, the latest batteries are designed to perform at full charge right up until the point they fail, which means there are fewer warning signs that your battery is about to die.

It is recommended to get your battery checked at least twice a year. Be on the lookout for acid stratification which happens when batteries dwell at a charge below 80% or never receive a full charge.

If you know that your battery is approaching the 5-year mark, it might be time to replace it and have peace of mind that your new battery is in the best possible condition.

Human Error

Anyone with an older car will have surely left their headlights on once or twice. Everyone makes mistakes and that’s precisely the reason why human error is one of the most common reasons for battery failure.

Your car battery is truly amazing in that it powers everything in your vehicle from the anti-theft system to Sat Navs and other electrical equipment such as phones, tablets etc. Make sure to give your car a break when you can; unplug your electricals and charge them at home instead.

Human error will always be an issue but remembering to turn your headlights off goes a long way in maintaining your battery life. In winter months, when it’s darker, the risk of leaving your headlights on is minimised as it’s more obvious to see when you’ve forgotten to turn them off. Most newer cars also feature automatic lights which switch off with the engine.

Parasitic Battery Drains

A Parasitic battery drain occurs when power continues to be drained from a vehicle’s battery even after the ignition is turned off. This is due to electrical devices such as your radio, security alarms or clocks continuing to run. The most common causes of parasitic drain are headlights, glove box lights etc. which do not turn off when the door is closed.

Any parasitic drains below 75 milliamps are considered normal but any above this figure will see your battery life drained quickly. Testing your battery for a parasitic drain is the easiest way to rule it out as a cause of battery failure.

Impact of Lockdown on Car Batteries

With Millions of UK cars left idle on driveways during the lockdown, motorists have been warned of the increased likelihood of battery failure. The estimation is that 1 in 20 motorists could find their vehicle refuse to start when they initially get back behind the wheel.

Turning your engine over as much as you can prevent battery failure. Even if it’s a short trip to the supermarket, starting your engine will decrease the likelihood of battery related issues.

If you’re not going out, you can turn the engine over until your vehicle is up to working temperature. This can be done whilst stationary, in your driveway or a parking space.

How to Prevent Battery Failure

Here are some things you can do to prevent battery failure:

• Start your engine regularly and leave your car running for a while
• Purchase battery covers to help protect against the cold
• Charge your battery throughout the colder months and if your vehicle isn’t being used often
• Check the age of your battery and replace it if it’s nearing the end of its life

At our Autocare centre in Chepstow, we can help you with replacing your battery. We can also provide servicing and MOTs which include a battery check to ensure that you aren’t at risk of battery failure.

If you’d like to book your vehicle in for an MOT or service, or have any questions regarding battery failure – give us a call on 01291 627137 or get in touch here.