How Long Does A Car Battery Last & When Should I Replace It?

How Long Do Car Batteries Last?

In today’s world, we’re used to being able to check the health of our battery-powered devices and tools with just a glance at the handy little symbol on a screen. 

With car batteries, however, it ain’t quite so simple. One day, we’re motoring along without a hint of anything awry and the next we’re stuck in the driveway, going nowhere, and googling the latest prices for electric cars.

Gauging when your car battery will punch its ticket is a tricky business.

Tricky, but not impossible.

Below, we take you through all you need to know about the life expectancy of car batteries.

How long does a car battery last? What are some signs its days may be numbered? And how do you know for sure it’s time to replace it?

All that and more is coming up.

Key Takeaways

No Definitive Answer – How long your car battery will last hinges on several variables

Extending Lifespan – There are ways in which you can extend a car’s battery life

Carry Jump Leads! – Because there’s no knowing when your car battery will go, it’s wise to always carry some way (jump leads or portable charger) to charge batteries on the road

How Long Does a Car Battery Last?

Ok, this is what you came here for, so let’s get to it.

The straight answer is – there is no straight answer. There are so many variables at play, there is no way to know with certainty how long your battery will last. Some of the factors that affect a car battery’s lifespan are: 

• Temperature (both heat and cold can cause battery degradation and shorten its life)
• Humidity
• Battery terminal post issues
• Level of demand (more electrical components means more work for the battery)
• How often the battery is charged (if unused and not charged often it won’t last as long – in which case, use a battery maintainer to prolong its life.)
• Cold cranking amps

That being said, the average car battery life for a gas- or diesel-powered vehicle is about three to five years.

Again, that’s just an average, and you might get more or less out of yours. If you live in a hot climate, expect a noticeably lower average life expectancy for your battery.

Based on this average, some mechanics recommend having a battery replacement fitted every four years just to be on the safe side.

That seems excessively cautious, and even with modern recycling methods, it’s still best to keep car batteries out of the waste stream. Our advice? Keep tabs on yours and get a replacement battery only when it’s absolutely necessary.

Check Your Warranty

It’s a pretty good rule of thumb that your warranty will be shorter than the manufacturer expects the battery to last. This applies to all consumer goods.

So, if your battery came with a 3-year warranty, you should expect at least that much out of it.

You’ll usually find a pretty direct correlation between battery life and cost, quality, and warranty length.

What Are the Signs of a Declining Car Battery?

Before your battery gives up the ghost entirely, it will probably send up a few warning signals. But, if you don’t know what they are, you might miss them.

Here are the things to look out for:

Slow Turnover

One of the surest signs of an imminent dead battery is a slow turnover when starting. Starting your car is the battery’s primary function, and if it can’t do that without a struggle, there’s a problem with the battery.

To recognize this sign you need to know the sounds of your vehicle pretty well. Listen carefully each time you start your car and you’ll know when something’s not quite right.

Slow Power Windows

A good battery has enough residual power to run your vehicle’s electrical components when the engine is shut off.

If you notice your power windows go up and down noticeably slower with the motor off than when it’s running, you may have a weakening battery power.

Dimming Headlights

With the car idling, pay attention to your headlights. Maybe pull up close to a wall so you can see the strength of the beams from the driver’s seat.

If the lights get brighter when you rev the engine, that’s an indicator the battery can’t supply enough power to the lights on its own.

Flickering Dash Lights

If you hadn’t noticed, there are a LOT of lights on a modern dashboard! Should you notice flickering or dimming lights on the dash when starting the car, it may be time to check on your battery’s health.

Leaking Acid and/or Corrosion

If you see any signs of sulfuric acid seeping from the battery or a build-up of corrosion around the terminals when you peer into the engine compartment, things are looking grim.

Testing the Health of Your Car Battery

Whether you suspect you have a battery problem or not, it’s always a good idea to keep tabs on its condition. You can do this by visiting your dealer, any service shop and asking the mechanic to test it.

For a reasonable fee (some places offer this service for free), you’ll find out if your battery’s capacity is diminished, and if there are any problems with the charging system, including the alternator. It’s a convenient way to check its health, and if there’s an issue, you can deal with it on the spot rather than finding it completely dead somewhere down the road.

You can also check your battery health at home with a dedicated tester or voltmeter. Owning one of these devices is the fastest way to get a read on your battery, and you can do it regularly without scheduling an appointment somewhere.

Battery testers aren’t badly priced, and they can provide a ton of information vital to understanding the health of your vehicle. Some even give you a printout!

If you think this would be a great addition to your garage, check out our article on the best car battery testers, as well as our detailed guide on how to test a car battery. 

How Can I Extend the Life of My Car Battery?

When it’s your battery’s time to go, it’s going to go, and there’s nothing you can do to keep it alive forever.

There are, however, ways to try and get the most life out of it you can. Here are some simple tricks for extending your car battery’s life:

• Keep the battery terminals clean
• Take the occasional long drive (short trips don’t allow your vehicle’s battery to fully recharge)
• Turn off your lights and accessories when the engine is off or idling
• Keep your battery fully charged by running your vehicle often
• Use a quality car battery charger. These portable chargers let you jump-start your battery without another vehicle. You can find more details on the charging process in our guide on how long it takes to charge a car battery.
• Disconnect it if it won’t be used for long periods of time
• Store your vehicle indoors if possible
• Ensure the battery is tightly secured to minimize damaging vibrations

All Good Things Must Come to An End

Hopefully, now your car battery won’t be so much of a mystery to you. It’s a vital part of your vehicle, and it’s important to give it some love now and then.

The time will come when your car battery needs replacing, but, armed with your new knowledge, it may not come as such a surprise.

If you’re in the market for a new battery, you should check out our article on battery types, groups, and sizes as part of your research. There’s more to the mystery!

As always, we’re glad you found us and trusted us to answer your most burning automotive questions. Thanks for reading!

If you have any questions about car batteries, drop us a line in the box below. And if you’d like to share this post online, please do!