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.
Some batteries, you buy and continue working for 10 or more years without issue. Sometimes, though, you install a battery and it gives up after only a couple of years. And there are numerous reasons a battery could throw in the towel so quickly — some of which have nothing to do with the battery itself.
Let’s dig deeper into the question of “how long does a car battery last” to find some reasonable answers, signs to look for, ways to maximize battery life, and more.
How long do car batteries last? The average car battery should last about three years, but the general range of a battery's lifespan is two to six years. You can also gauge a battery’s life by its warranty, which you can usually find on the battery case or label. The longer the warranty, the longer the manufacturer expects it to last. Let’s review some of the most common variables that affect battery life.
You know the adage "you get what you pay for," which 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 in a shorter amount of time.
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 sitting idle on a store shelf, a battery loses life.
If you buy a new car battery from a volume seller, 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.
How do you know a battery has sat on the shelf for a while? Check the build date. You’ll find an alphanumeric code on the top of the battery case that reads something like “B7CM".” The first letter is the month and the first number is the build year. The letters A through L correspond with January through December in order (A=January, B=February, and so on).
The numbers 0 through 9 correspond with the manufacture year, but this goes in 10-year cycles, so it can be tricky. In most cases, 1 will equal the first year of the decade you’re currently in. For example in 2023, a 0 would equal 2020. However, there is a slight chance it could also mean 2010, though that’s highly unlikely.
Some batteries may not have a manufacture date or are unclear. In this case, visually inspect the battery to guess if it’s been sitting for a while. Check for a faded or peeling label, dust and debris collecting on it, and other signs of age.
Where you live significantly impacts a car battery's life, particularly if you climate is subject to 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 shorten 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.
Have you ever opened your hood to find no battery? Sometimes a car battery is located in the wheel well or even in the trunk. This isn't always 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 favourite place for many automakers, as it's away from the engine's heat and still easy to access.
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.
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.
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, leaving your car sitting for long periods, you could shorten 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 a passthrough and a storage unit, capturing excess power from the alternator.
If you start your vehicle and take a short trip, 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.
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 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.
Your car will often fire right up and work fine from that point forward. However, sometimes a jumpstart isn't enough, and you’ll need to replace your battery. What generally happens in this case is the vehicle will start just fine, but dies as soon as you disconnect the jumper cables or jump pack.
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, simulating 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.
A bad battery has several warning signs, but 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.
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, but it could also mean more serious repairs are due, such as a new alternator.
The charging system requires a completely 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.
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 often accompanies this.
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.
While a car battery has a finite lifespan, you can maximize its longevity. Here are some tips to keep your battery in great shape as long as possible.
As we mentioned, cold Canadian winters can freeze your battery. You can protect your battery from freezing by buying a thermal battery blanket. You 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 during the first battery replacement. You can buy a replacement online that helps protect it from under-hood heat.
If you have a garage, park your car in there to keep it out of extreme temperatures when the car’s not running, which is when it’s most susceptible to freezing. If your garage is cluttered, this is the perfect excuse to straighten it up and make room for the vehicle.
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 prefer a constant slow charge.
If you rarely drive your vehicle or only drive it short distances, a trickle charger or battery maintainer may be an excellent option to extend your battery life. These work by applying a low-voltage charge to the battery, giving it the small amount of juice it needs to stay alive and maintain its temperature in cold weather. When you're ready to drive, just disconnect the charger, and you're on your way. Many of these chargers are very easy to use and plug directly into your car’s existing 12-volt power outlet or cigarette lighter outlet.
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 maintenance mode.
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 enough time to warm up the engine bay and recharge the battery juices. 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.
Whatever you do, make sure you get your car out on the road for 10-20 minutes every day in the winter.
Battery terminals corrode — that’s just the way the world works. 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 and the terminal ends (the clamps on the end of the battery cables).
This corrosion is mostly harmless, but it can interfere with the power flow and slow the battery's recharging or impact its ability to deliver power to start the engine. You can easily clean this with 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. While you’re at the auto parts store, they often sell a coating that helps limit corrosion too. Pick this up and apply it after cleaning up the existing corrosion.
Regular battery test 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 must ask for it, though. If they don’t offer it for free, it’ll be relatively inexpensive and well worth the peace of mind.
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 without asking yourself “how long does a car battery last?”
Plus, our car-buying process is 100% online. We also offer easy financing and 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.