How long does a car battery last? Mechanics will often joke that the answer to this question is: until it doesn't work. While that's not a response that inspires confidence, there is some truth to it. There are many variables that come into play when figuring out a battery's lifespan. 

Sometimes, you'll buy a battery that seems to never quit. Other times, the battery throws in the towel after just a few years.

In this guide, we’ll cut through some of the clutter surrounding the lifespan of car batteries, including how long they usually last, what impacts their longevity, when you need to replace the battery, and how you can prolong your battery's life.

How Long Does a Car Battery Last?

On average, your car battery should last about three years, but the general range of a battery's lifespan is two to six years. Let’s review some of the most common variables that affect battery life.

Initial Battery Build Quality 

You know the adage "you get what you pay for," and this rings true for car batteries. If you head to the local discount store and pick up the cheapest battery possible, it could have inferior components and manufacturing processes that lead to more battery problems.

Battery Age

No, we’re not talking about how long the battery's been in the vehicle. We mean how long it sat on the shelf in the store before being sold. Even when sitting idle on a store shelf, a battery is losing life. If you buy a new car battery from a volume seller, then you can be confident it hasn't been sitting on a shelf for long. However, if you buy a battery from a small shop with little traffic, there's a good chance it has exhausted most of its battery power while collecting dust.

Where You Live

Where you live significantly impacts a car battery's life, particularly if there are extreme temperatures. Heat is a battery killer as it increases the degradation rate. While we don't have to worry about scorching summers in Canada, you could be shortening your battery's life expectancy if you travel south during the summer.

Don't get too confident, though. Car batteries are no cold-weather fans either. A fully-charged battery can feel significantly weaker during icy Canadian winters. Even worse, a half-charged battery can completely freeze once the temperatures reach -23 degrees Celsius.

Battery Positioning

Have you ever opened your hood to find no battery? Sometimes a car battery is found in the wheel well or even in the trunk. This isn't for the sake of weight distribution, but rather to help your vehicle's battery last as long as possible. 

Moving the battery from the engine bay to a cooler environment will dramatically increase its lifespan. The trunk has become a favorite place for many automakers, as it's away from the engine's heat and still easy to access. 

Battery Installation

Vibration can speed up the breakdown of your vehicle's battery. Most cars have a battery hold-down system to minimize vibration, but some owners don't realize how important this is and never reinstall it when replacing a battery. Without this hardware, your battery will vibrate and sometimes shake violently, which can lead to a dead battery in no time. 

Vehicle's Mechanical Health

The mechanical condition of your car can have a huge impact on battery life. Your battery relies on the transfer of engine power to the alternator, which generates electricity to charge the battery and run the electronics while the engine is running. 

The alternator should usually generate 13.5-14.5 volts. Of that power, approximately 12 volts run the vehicle electronics — computer, fuel injection, car radio, air conditioner fan, headlights, etc. — and the remaining 1.5-2.5 volts flow to the battery as a maintenance charge.

If there’s a breakdown in this system — be it a bad belt, bad alternator, or bad wiring — your battery may not receive ample charge and endure excessive stress. This can reduce the battery's lifespan. 

Driving Habits

Your car's battery requires frequent maintenance charging, and your alternator can handle this on mid-range and long trips (i.e., those 10 minutes or longer). However, if you typically take only five-minute trips to the grocery store and back once a week, you could be shortening your battery's lifespan. 

Starting the vehicle is the most stressful point for a battery because this is the only time the battery does 100% of the work. Otherwise, the battery acts as more of a passthrough and a storage unit, capturing excess power from the alternator. 

If you start your vehicle and take a short trip down the road, you've put the battery under immense stress to start the vehicle without driving far enough for the alternator to recharge it. Doing this repeatedly can dramatically limit the battery’s life.

What Can You Do If Your Battery Dies?

It happens to almost every car owner at least once: You head out to your car, turn the key, and you get nothing but clicks or a slow cranking sound. It's a dead battery. 

What's next? Do you have to go buy a new battery? 

Not necessarily. You can use another vehicle or a battery-powered jump pack to jumpstart your vehicle. This is when you use an outside power source, like another car's electrical system or a battery, to start your vehicle. From there, your vehicle's alternator can take over. 

In many cases, your car will fire right up and work fine from that point forward. However, there are times when a jumpstart isn't enough, and you’ll need to replace your battery. 

How Can You Determine Your Battery Needs Replacing?

You can't accurately deem a battery as failed without a load test, which shops use special equipment to perform. This special equipment puts the battery and charging system under loads, meaning it simulates various accessories drawing power from it, at different times. Doing this helps determine if the problem lies in the battery or charging system as they often have similar symptoms. 

There are several warning signs of a bad battery. Keep in mind, these can also be signs that the charging system is failing, so you'll want to have a shop perform a load test before replacing the battery.

Battery Light Is on After a Jumpstart

The biggest telltale sign of a bad battery is the battery light — a red warning light in the shape of a car battery — or the "check charging system" warning displays on the gauge cluster after getting a jumpstart. This means the self-diagnostic system detects abnormal power flow in the charging system, and that could mean it's time for a battery replacement. 

Car Stalls Once You Remove the Jumper Cables

The charging system requires a complete healthy circuit to run. If your battery is bad and breaks the circuit, the power can't make it to critical components required for the vehicle to run. Once you attach jumper cables, it creates a new, good circuit. However, once you disconnect the jumper cables, that good circuit breaks, forcing your car to shut down. This is a common sign of a bad battery that needs replacing. 

Car Runs Poorly After a Jumpstart

In the same way a car will die after a jumpstart, a bad battery may allow enough power to flow to let the vehicle run, but it'll run roughly. You may experience rough idle or rougher-than-usual transmission gear shifts. These symptoms will likely worsen as you turn on accessories like the air conditioning, headlights, or radio. A “check engine” light oftentimes accompanies this.

Lights Dim When You Turn on Other Accessories

It's perfectly normal for your headlights to flicker for a second when you turn on an accessory, like the air conditioning. It takes a second for the alternator to adjust to the extra power demand, leading to that flicker. However, if your headlights remain dimmer when you turn on an accessory, this could be a failing battery. 

How Can You Maximize Your Car Battery Life?

While a car battery has a finite lifespan, there are ways to maximize its longevity. Here are some tips to keep your battery in great shape as long as possible. 

Battery Blanket

As we mentioned, cold Canadian winters can freeze your battery. You can protect your battery from freezing by buying a thermal battery blanket. You simply wrap the blanket around the sides of the battery — avoiding the battery terminals — and plug it in. This will keep your battery from freezing overnight. 

A blanket works well in the heat too. Most manufacturers install thin insulation around the battery at the factory, but this often gets thrown out or forgotten about during the first battery replacement. You can buy a replacement online that helps protect it from under-hood heat. 

Park in the Garage

If you have a garage, park your car in there to keep it out of extreme temperatures. If your garage is cluttered, this is the perfect excuse to straighten it up and make room for the vehicle. 

Keep It on Charge

You may remember older cellphones and laptops and their overcharging issues, but the lead acid batteries in today's cars don't suffer from that issue. In fact, they thrive on being charged. 

If you rarely drive your vehicle or only drive it short distances, a trickle charger or battery maintainer may be a good option to extend your battery life. These gadgets slowly recharge the battery, giving it the small amount of juice it needs to stay alive. When you're ready to drive, just disconnect the charger, and you're on your way. 

In extreme cold, these trickle chargers may not be enough. If you frequently endure sub-zero temperatures, you may want to invest in an advanced battery charger. These chargers automatically sense the battery's condition and recharge it as needed. Once it completes the recharging process, it automatically switches to a maintenance mode. 

Take a Daily Wintertime Drive

Even if you have no errands to run, plan to take your car for a 10- to 20-minute drive every day during the winter — and don’t forget to add in those winter tires.

You need just enough time to warm up the engine bay and get the battery juices flowing again. Maybe plan to grab a coffee at the cafe across town instead of around the block or check out the grocery store in the next town over. 

Whatever you do, just make sure you get your car out on the road for 10-20 minutes every day in the winter.

Crush the Corrosion

Battery terminals corrode, and there's no stopping it. When the battery charges, it heats, which causes the sulfuric acid inside the battery to turn into hydrogen gas. This hydrogen gas has a chemical reaction with the lead on the battery terminals, causing the whitish corrosion you often see on battery terminals. 

This corrosion is mostly harmless, but it can interfere with the power flow, slowing the battery's recharging or its ability to deliver power to start the engine. You can easily clean this with a mixture of 1 tablespoon of baking soda to 250 mL of hot water. Dip an old toothbrush in the mixture and scrub off the corrosion. 

If the corrosion is stubborn, you can pick up a terminal cleaner and metal terminal brush at an auto parts store.

Check It Often

Regular battery and charging system checkups are crucial for catching problems before they leave you stranded. Many auto repair shops will perform a free starting and charging system analysis during an oil change — you simply have to ask for it. If they don’t offer it for free, it’ll be relatively inexpensive and well worth the peace of mind. 

All Charged Up at Clutch

Though they can be aggravating, battery issues are relatively small problems in the automotive world. Here at Clutch, we make sure the car you buy has a good battery and won't leave you stranded. 

All of our quality pre-owned vehicles go through a 210-point inspection, including a battery and charging system test. This will help ensure you have trouble-free driving. 

Plus, our car-buying process is 100% online, we offer easy financing, and we deliver your vehicle to you. You then have 10 days to try the vehicle risk-free. If you don't like it, you can return it for a full refund or exchange it for another vehicle. 

Plus, all Clutch vehicles purchased online include a 90-day or 6,000-km limited warranty. So, if any issue does arise, you know you're covered.