How Long Does A Car Battery Last?

A car battery is something most drivers don’t think about until it’s too late. Maybe you just had to jump a car or your battery is getting old, but how long do car batteries last anyway?

We’ll explain average car battery life in this article and share a few tips on how to get the most out of your vehicle’s battery.

Disclaimer: Working with car batteries poses risks such as electric shock and potential damage to vehicle systems if improperly handled. Please use caution while attempting any vehicle maintenance and always consult your car manufacturer’s manual.

The average lifespan of a car battery is around three to five years, according to AAA, although there is no true expiration date on a car battery. Car battery life is determined by a mix of driving habits, car maintenance, and other external factors.

How Does A Car Battery Work? 

Car batteries create electrical currents through chemical reaction. Housed in every battery are sulfuric acid and two lead plates. The lead plates produce electrons after coming into contact with battery acid.

Those electrons move across the plates to create electricity, which is transferred from the battery terminals to the engine and the vehicle’s electrical system. The process can be reversed, which is why you can use a jump start to revive a dead battery. 

All car batteries die eventually, either from general degradation or external factors. While there is no true average, automotive batteries usually offer around three years of reliable service. After that, the battery starts to degrade from within, leading to an inconsistent charge and a drop in performance.

Corrosion 

Corrosion is a common concern with batteries, as the sulfuric acid within car batteries emits hydrogen gas over time. This gas then mixes with moisture, salt, and air, leading to the buildup of grime on your battery.

Corrosion can form in a number of ways. It can occur naturally as a car battery ages. Overheating or physical damage can create an acid leak. Besides being unsightly, corrosion can lead to several battery problems like poor connection to the car’s electrical system or power reduction.

Bad Parts

If the bits and bobs that transfer power from the rest of the vehicle are faulty, this can also lead to the battery losing charge. A bad alternator can result in a dead battery because it won’t allow the battery to build up a charge.

Shoddy cables and belts can also limit the transfer of electricity to the rest of the engine. Additionally, vibrations from the vehicle itself can damage a battery’s internal components. It is worth making sure your battery is securely fastened to the battery case a few times each year. 

The Elements

Extreme temperatures are another factor that impacts a battery’s performance. Below-freezing temperatures can cause fluctuations in power, and heat increases corrosion and deterioration of the battery.

Not Enough Use

Driving your car is what charges the battery, so keeping it parked or stored for long periods of time could leave you with a dead battery. Short trips, under 30 minutes of driving, usually aren’t enough to fully charge your battery. Many auto professionals recommend at least 30 to 45 minutes of driving at highway speeds once a week to fully charge your battery.

Here are some warning signs that may mean a battery replacement is in order:

• You regularly have to jump-start the car 
• Headlights are dim/flickering
• Dashboard lights are dim/flickering
• Check engine light/battery light is illuminated

You can also assess a car battery with an automotive multimeter. A multimeter is a handheld device that can read electricity metrics like currents and voltages.

To read a car battery’s charge with a multimeter, set it to 20.0 DC volts (V) and place the negative and positive probes to the appropriate battery terminal. A fully charged battery should read around 12.6 V. If the reading is higher than 12.6 V, which would suggest overcharging, it could be due to the vehicle being driven recently. 

If you don’t have a multimeter, auto repair shops can perform a battery test and review your vehicle’s charging system. There are also jump starters, battery chargers, and other battery maintainers that can be used at home.

If you are in the market for a new car battery, you might want to check out our buyers guide to some of the top car battery options on the market. To summarize, here are a few things to know.

Group Size

A battery’s group size determines what battery case it will fit. This is designated by a number often printed on the side or top of the car battery. Group size varies across automakers because different vehicle categories require different mounting configurations and other power considerations.

Warranty

Warranties on car batteries vary by model, manufacturer, and price point. Cheaper car batteries may only offer a year of coverage, whereas premium models may extend two or three years. As mentioned above, the first few years of battery life are usually reliable, but if you find yourself with a damaged battery or in a harsh climate, a new car battery may be in your future.

Reserve Capacity And Cold Cranking Amps

These are two terms you may hear when considering car batteries. Here’s what they mean in relation to your vehicle.

• Reserve capacity: Reserve capacity (RC) refers to how long the battery can run vital systems before a drop in power.
• Cold cranking amps: Cold cranking amps (CCA) is the amount of energy a battery can produce when starting a cold engine. A larger CCA means it can produce more power.

The cost of a new car battery can be between $100 and $300, depending on the model, size, and any installation costs. Disconnecting a battery is relatively simple and can be done at home with the proper equipment, although having it done at an auto shop should take less than an hour.

*Data accurate at time of publication.