How long does a car battery last on average?

If you are asking yourself "how long does a car battery last?" - you are probably facing car battery difficulties. Car batteries do not last forever and it's important to understand that the average car battery lifespan depends on many factors, average battery life can span between two and five years.

If we consider perfect conditions for a battery to perform, a maximum of five years is to be expected on average. However, if we presume normal conditions with eventual wear and tear, the battery should last approximately three years on average.

Vehicles have evolved, a few decades ago cars did not nearly have as much electronics as they do now, which means that they require more power to run. Back then, car batteries would last much longer, today car batteries don't last nearly as long. The increased power consumption puts more pressure on the battery to perform and this decreases the life expectancy of the battery.

A car battery test checks a few things before determining the overall health of the car battery. The test includes checking the battery voltage, cold cranking amps (CCA), and the current physical condition, including any case damage, electrical leaks, and or battery terminal corrosion. More importantly, we test the charging system of the car which is also commonly known as the alternator.

These benchmarks contribute to determining the remaining car battery life expectancy, it is therefore highly recommended to get a car battery test as a dead battery can leave you stranded on the side of the road, being proactive and having your battery tested professionally can save you a lot of time, pain and money.

Why do car batteries die?

Car batteries are designed to start the vehicle, they do this by providing a high concentration of power to the engine, once the engine has cranked over it is the job of the alternator to keep the battery constantly charged.

There are many factors that contribute to shorter battery life, some notable factors include:

Age

Over time, batteries naturally lose capacity and power and eventually may not be able to hold charge providing enough power to start the engine, this is a normal occurrence as car batteries only perform for so long. Be mindful that the average car battery lifespan ranges from two to five years, if your car's battery is old than three years then it is possible you may need to get a replacement battery.

Slow discharging/recharging

Car batteries if left stationed in a vehicle without charging can cause power loss over time, small electrical currents drain the battery, and without a recharge, it may lead to a dead battery. There are electrical components in the car such as the security system that still run even when you think the car is completely turned off, the power drain is not immense but over time it will gradually draw power reducing the car battery's lifespan and leading to a replacement battery much earlier than anticipated.

Structural failure:

The internal design of a car battery is made up of lead plates submerged in sulfuric acid, lead acid batteries are constantly exposed to rapid changes in their environment, and they undergo a lot of stress throughout their use. This can cause internal structural failure or most commonly known as a "dead cell" - the electrolyte solution inside of the cell dissipates and becomes exposed to air, when this happens the battery will simply stop holding charge at full capacity.

Extreme temperatures:

Extreme hot and cold temperatures can shorten the battery life. Heat causes the electrolyte solution to evaporate whilst cold temperatures cause the electrolyte solution to thicken, in both cases the battery is no longer able to function properly. Location plays an important role in your car battery life cycle, suburban environments with moderate temperature fluctuations see an increased lifespan whereas rural climates with extreme temperature fluctuations see an earlier battery failure.

Corrosion:

Over time, the battery terminals connected to the battery can become corroded which prevents a stable connection between the battery and the car's electrical system, an unstable connection causes improper charging leading to a loss of power in the battery. Corrosion is a chemical reaction caused by acid gases rising to the top which react with the metal terminal, through this reaction the condensation of the gases solidifies forming a build-up of white or green-like powdery residue.

Rapid discharging or overcharging, or alternator failure:

Car batteries are not meant to be discharged or overcharged. Rapid discharging can cause the electrolyte solution to separate leaving which forms into gunk that is collected at the bottom of the battery. Overcharging can cause the battery to cook the electrolyte solution, the solution will burn and evaporate into gas leaving a weaker electrolyte ratio predominately made up of water, this can also be dangerous as it may lead to the battery case to bulge or even explode. The alternator is responsible for charging the battery, if the alternator is not functioning properly, it can overcharge or undercharge the battery, both cases leading to early battery failure.

Short trips:

Driving the car only for short trips can cause early failure, the driving habits of an individual can determine the outcome of their battery's lifespan. Short trips do not allow the alternator to recharge the battery properly, this shortens the lifespan of the battery and a battery replacement will be required sooner than anticipated.

Overloading:

Anything electrical uses power and if your engine is switched off whilst they're on it will drain the battery quick, things such as headlights, audio systems, GPS, phone chargers and many more will overwork the battery. Remember, the main purpose of a starting battery is to crank over the engine and not to lower battery voltage through electrical drains, that is what a deep cycle battery is used for.

Vibration:

It loosens the terminals leaving an unstable connection accelerating corrosion due to undercharging and it also damages the internal battery plates causing them to fracture and warp. This is why most cars have a bracket that holds down the new car battery in place keeping them sturdy in an effort to minimise as much vibration as possible.

What are some common symptoms of car battery failure?

The only way to tell if a car battery needs a replacement is to test it, special testing tools measure the cold cranking amps, battery voltage, internal resistance, state of capacity and state of health. If you cannot obtain these tools have it tested by a professional or check out the most common symptoms - remember if it's giving you trouble and it's more than three years old it may be time to book a replacement battery.

Corrosion around the terminals:

If there is a white, powdery-like stain building up around the positive terminal and the negative terminal then you are looking at terminal corrosion. This is a sign that the battery is either being overcharged or nearing the end of its life.

Click but doesn't crank:

If you try and switch the car on and all you hear is a constant clicking noise, what it means is that the battery has no power to crank over the engine, you might notice all of the lights turn on in the dashboard, however, the engine won't start. You can try to jump-start the battery or use a charger, If you have already tried that and it won't turn on then it is time to get it replaced.

Slow engine turnover:

This is a common battery problem and it means that there is not enough power provided for the engine to crank over fast, this is because the overall cranking amp capacity has fallen drastically and the battery can no longer provide the once CCA rated in its original state.

The battery smells:

Batteries let out certain gases, if you smell a rotten-egg-like scent coming from your battery then it is a sign that your battery is being overcharged, this can cause your new battery to fail prematurely.

How to increase a car battery lifespan

If you're looking to make a battery last longer

Use a charger: If you're going away on long trips or do not intend on using the car for a while, use a battery maintainer, this keeps the battery topped up while you are away and does not allow the voltage to drop keeping it in good shape.

Clean off the corrosion: If you notice corrosion build up around the terminals, clean it off by using a spray you find at your auto parts shop or hot water or baking soda mixed with water, this neutralises the corrosive material and allows solid connectivity to the battery.

Don't leave accessories running all the time: Remember, starter batteries aren't designed to be discharged deeply so do not leave your accessories running while the car isn't moving, this will ultimately kill the battery quicker.

Get it tested: If you're unsure what condition your battery is in then get it tested, book a test with our technicians and we can tell you the next steps you need to take, treat it like a dental checkup for your car and the best thing about is - it's free!