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Your guide to understanding your car battery

Car battery

A battery's primary purpose is to supply power to the starter motor and other components of the vehicle, including lights, fans, and the radio, when the engine isn’t running. Basically, your car won’t run properly without a reliable battery.

There are some warning signs you should be aware of to avoid an unwanted breakdown of your car due to battery failure. If you suspect your vehicle’s battery is not functioning as it used to, please have a read of this article, and reach out to Donnellans for professional assistance as soon as possible.

How long do car batteries last?

Car batteries are like tyres, brake pads, headlight bulbs, and more; they are consumable items that wear out with use. There are multiple factors that will determine how long your car’s battery will last. This includes the following:

The age of the battery: Typically, a car battery will last for 3 to 5 years.
Weather or environmental conditions: Generally, batteries are affected by extreme temperatures. For example, extreme heat can result in water loss and heat distortion, causing battery damage.
Use: Vehicles that see a lot of short trips will, over time, damage the battery faster than vehicles that primarily see longer trips. Starting the engine in your car takes tremendous amounts of energy and over time can affect battery performance.

What are the common signs of a faulty car battery?

Corroded battery

There are some signs to look out for if you think your car’s battery is faulty or old and needs to be replaced:

Corrosion. A typical sign of a faulty battery is the build-up of acids on the terminals or corrosion. This corrosion takes the appearance of a blue or white powdery substance. This can lead to voltage issues that prevent your car from functioning. Also, it could mean the battery is not charging effectively.

You may attempt to clean your battery terminals with a mix of baking soda and water. The soda will neutralise harsh acids and chemicals. However, if the corrosion reappears, chances are your battery is in the late stages of failure.

Lifespan. Typically, the lifespan of a battery is between 3 and 5 years. Pushing it longer than 5 years could cause your battery to fail without notice, even under perfect driving conditions. Keep a record of when you last changed your battery so you can tell when it's time for a new one. We recommend checking your battery annually or before a road trip if it is more than 3 years old.

Slow cranking. A slow-turning engine crank is a common indicator of a faulty battery. As a car battery's parts deteriorate and lose efficiency, the battery will struggle to produce enough current to start your engine.

Level indicators. Many modern batteries are sealed units that do not require refilling. But if yours is the refillable type and you notice there is a drop in fluid levels in your battery, it can be an indication that the battery is overheating. The level indicators are located on the side of the battery, and you can check the fluid levels against the information provided in your owner’s manual. Overheated batteries are either a symptom of a faulty alternator, or some kind of heat management issue under your engine bay.

There are other warning signals you should be aware of, such as dimming lights, a bloated or swollen battery case, or a failed alternator.

If you have noticed any of the symptoms mentioned above, it might be time for a battery replacement.

What types of car batteries are there?

Battery types

Lead-acid battery

You will find a lead-acid battery in most of the cars on the road. It’s one of the cheapest available and provides great reliability. Compared to other batteries, this one has a relatively short lifespan.

Absorbent Glass Mat

The Absorbent Glass Mat (AGM) battery has similar technology to the lead-acid battery, but in this case, the liquid electrolyte is absorbed into a fibreglass mat rather than being flooded into the battery. This provides a much higher current capacity needed by modern vehicles with start-stop technology. These batteries are non-spillable, resistant to vibrations, and able to provide starting current at lower voltages. Their lifespan is roughly twice that of a lead-acid battery, but they come at a higher price point.

Spiral Coil AGM

This is a variation of the AGM battery. They have similar functions to AGM batteries, but they provide a higher starting current, a much more rugged construction, and the ability to be fast-charged. This type of battery is generally used in off-road or high-performance situations where a higher cranking current is required for larger displacement or high compression engines.

Lithium-Ion Battery

Typically, lithium-ion batteries are used in hybrid and electric vehicles. They lack memory-retaining characteristics and are capable of maintaining a constant output over a wide range of charge levels. You can find traditional-style car batteries in most fully electric vehicles, which provide power for onboard electrical systems.

When should I get mine checked?

If your vehicle's battery is more than three years old, regardless of whether or not it displays warning signs, it is advisable to have it inspected annually. The team at Donnellans is your go-to source for vehicle battery advice. By making sure your car battery is in good shape, they can help you avoid unnecessary stress and expense should you experience unexpected battery failure.

Donnellans provides and instals top-notch batteries. Your local Donnellans centre in Victoria can offer the complete fitment of battery to most makes and models.

With 4 convenient locations in Prahran, Blackwood, Collingwood, and Balwyn, we can assess and advise you on the condition of your battery and provide advice for a replacement battery should one be needed.