How long do car batteries last?

Batteries keep the engine ticking over by providing power. Unfortunately, they have a finite lifespan and may need a replacement. So, how long do car batteries last? Whether you have replaced your battery or still using the original, it is important to understand its lifespan.

Find out what to expect from your car battery and warning signs that indicate you need a replacement.

Average battery lifespan

Batteries are the heart of every vehicle. Unfortunately, they deteriorate until they can no longer start an engine. Most car batteries have an average life span of three to five years. During that period, they can hold their charge and are capable of recharging. Under normal conditions, a car battery can last up to four years. These conditions include protection from extreme temperatures, full charge cycles and a consistent charging system. Unfortunately, normal conditions are impossible to maintain in the real world.

Aside from the conditions above, the chemical composition also affects the lifespan of a car battery. For instance, lead-acid batteries last 3-5 years since many factors can interfere with the chemical composition. Vibrations from cruising a rough or a poorly secured battery can damage the battery plates. The chemical reaction speeds up in extreme temperatures, shortening the battery's lifespan. Nowadays, some cars use dry cell lead-acid batteries to last up to seven years.

Electric vehicles rely on lithium-ion batteries with a long lifespan of 10 to 20 years, while hybrid cars use Nickel-metal hydride that lasts eight years.

What causes a car battery to die?

Car batteries are designed to provide a high-amperage current and power to start a car and maintain a charge when the car is running. Some of the reasons that cause car batteries to die include:

Slow discharging

Vehicles usually have an alternator that maintains 12.6 volts when running. When the battery is unattended, it slowly discharges from the 12.6 volts. Unfortunately, a car battery shouldn't discharge below its starting cycle. Slow discharge occurs when you leave the car battery in a vehicle that hasn't been started for a long time. The car's parasitic drain steals the voltage, and you have to jumpstart, which means the alternator is charging a dead battery. Restarting a battery that has lost its charge reduces its recharging ability over time. Slow discharging often occurs in low temperatures since the battery loses its ability to maintain a charge and needs more amperage to start.

Structural failure

Vehicle batteries are made of lead grids submersed in electrolytes like sulphuric acid. The batteries are usually bumped around during car movements. Not to mention rapid temperature changes during freezing winters and hot summers that affect temperatures in the engine compartments. After some time, the wear and tear can lead to structural failure. The battery's failure can also be due to the loss of electrolytes, exposing the cells to air.

Alternator failure

The alternator maintains the battery's starting charge at 12.6 volts for optimal performance and recharging. When the alternator fails, it can overcharge the battery, causing leakage of electrolytes or boiling over, which eventually destroys the battery. When the opposite happens, the alternator stops charging the battery. The vehicle's ignition system runs off the battery, leading to a quick drain. When the alternator isn't charging the battery, it triggers a batter light, and if you resolve the alternator issues, you can save the battery. Unfortunately, the battery and alternator usually fail simultaneously as the alternator due to rapid discharge, making it hard to discover the problem on time.

What factors affect a car battery's life span?

Initial battery build quality and age

The quality of battery components determines the duration of its life span. If you pick a poor quality battery, the inferior manufacturing process and components lead to problems within a short time. Battery age also affects the lifespan. The age doesn't refer to the duration it has been in the vehicle but the manufacturing time. How long has the battery been on the shelf? Since a car battery ages when sitting idle on a store shelf, you should ensure that the manufacturing date isn't a few years back.

Battery positioning and installation

Did you know that sometimes batteries aren't found in the bonnet? Some car manufacturers place the battery in the boot to balance weight distribution. Moving the battery to a cooler environment or away from the engine bay also improves its life. Positioning it in the boot is becoming popular since it is easy to access and away from the engine's heat. Battery installation also affects the lifespan since it determines the vibrations. Vehicle movements often create vibrations that can cause battery breakdown. Most car manufacturers have a battery hold-down system to reduce vibrations. Without the hardware, you will have a dead battery in no time.

Driving habits

Batteries self-discharge slowly when unused. Hence, you should avoid leaving your battery stationary for long periods. If your car has many onboard electronics, the battery will drain faster to support the electronics. You need to ensure the car charges frequently. This can be achieved with mid-range and long trips. If you drive short distances of less than 10 minutes in a week, you could be straining the battery since it drains faster than the recharge. Starting a vehicle stresses the battery since it does 100% of the work. If you start the car and take a short trip, the alternator will not have enough time to recharge it. You should make a few long trips weekly to charge your battery and improve its lifespan.

Temperature

While high-temperature aids in the chemical reaction that generates electricity, it accelerates battery degradation. Temperatures also cause battery problems. It is easier to start a car in warm weather than cold weather. Extremely hot temperatures can lead to evaporation of battery fluid and damage to internal cells. That's why batteries last three years in hot regions, while they can stay for five years in cold areas.

Signs that your car battery may need a replacement

When your battery is older than three years, you must pay more attention. Although you won't always know that a problem is brewing in your battery, some signs can help you discover the problem early. Check for the following signs:

Signs of corrosion or leakage

While corrosion on car battery terminals is common with ageing batteries, it also indicates terminal failure or problems with the charging system. You should also check for signs of acid leakage. It indicates over-charging or structural failure.

Sudden click, but no start

When you turn the key and get a buzzing or click, chances are your battery is dead. While you can jumpstart the vehicle and continue using it, the battery can fail at any time. You need to charge the battery or get it tested. If the battery is healthy, there's likely a hidden element drawing too much power.

Battery-related dashboard lights are on

When the dashboard lights are on, you should test the battery for failure. It may also indicate problems with the alternator that require a mechanic. Dim headlights and electrical problems can also indicate battery problems. Electronics and the starter rely on the battery to function properly. A weak battery will struggle to power your electronics, and the headlights will be dim.

Slow starting

If the engine takes longer to spark to life, it is a sign of trouble. You'll be lucky to get a few cranks before the battery dies. Over time, you will notice deviations in cranking speed, but the problem is accentuated when the battery fails.

Unpleasant smell

Sulphuric acid usually smells like rotten eggs. If your car has such an unpleasant smell, it shows signs of leakage and battery damage. Your battery needs to be checked for internal structural failure or overcharging.

Tips to get the most out of your car battery

1. Use a maintainer

Since a slow discharge can kill a good battery, you need a maintainer between long engine starts. The maintainer keeps an on-demand, low-amperage charge to prevent slow discharge in batteries.

2. Remove corrosion

You should periodically check for corrosion on the battery terminals. Keeping the posts and clamps clean using battery corrosion washers is crucial. You can also prevent corrosion using dielectric grease.

3. Do not remove the heat blankets

Cars usually have heat blankets or protective shields around batteries. Over time, the shields are removed or discarded. The blankets protect the batteries from the hot engine, and removing them can reduce the battery's lifespan.

4. Don’t power electronics for long

Your vehicle's battery is for starting the car, not powering electronic components. Car batteries aren't suited for frequent discharge and recharge, and electronics drain power faster. If you like having the stereo on, consider having an auxiliary battery.

5. Test your battery regularly

During car servicing or maintenance, ensure your battery is tested. Some problems can be fixed to improve the lifespan of your battery,

Conclusion

While a car battery doesn't last forever, you can maximise its life. How long your battery lasts relies on the measures you put in place to care for your car. Pay attention to signs of failure and keep your battery charged to prolong its life.