7 ways to extend the life of your car battery


When it comes to cars there’s nothing worse than being stuck with a flat battery. We’ve all been there at some point in our lives, and the problem is often made worse from the fact that with modern vehicles there is little to no warning signs shown prior – and probably a 50% chance that it’ll occur while you’re out and about away from home.

Just like the battery in your mobile phone or laptop, lead-acid car batteries have a limited life span and will eventually lose their ability to hold sufficient charge to start your car. On average you can expect a lead-acid battery to last around 42 months, but this time-frame will vary depending on a number of variables – such as hot or cold climates, journey lengths and the performance of your car’s charging circuit.

But regardless of what conditions your car is subjected to, here are 7 tips you can consider to help get the very best out of your battery.


1. Avoid driving short trips often

Your battery is given a workout every time you start your car, but is then recharged by the engine during the journey. So if you are only driving a short distance it will be impossible for the battery to regain the amount of power lost – and if you repeat the process daily the battery voltage will reduce steadily until it can no longer start the car.

Maintain your car’s battery power by driving it frequently and for longer periods of time – and if you don’t use your car very often, consider investing in a battery charger to help maintain the correct voltage.


2. Keep your battery tightly fastened

Vibration can reduce the life of your car battery, so it is vital that you always use an approved battery clamp to ensure it is properly held down at all times. If not securely fastened, excessive vibration could damage your battery’s internal components – creating short circuits and reducing battery life.

But don’t make the mistake of over-tightening the battery clamp nuts to the limit of your strength – because you might damage the battery! Instead, simply tighten the nuts until you feel the resistance start, and then continue for only an additional half turn.


3. Minimise power used while engine is off

Car batteries are happiest when they are kept close to 100% charge – so keeping your headlights or interior lights on while the engine isn’t running is a big no-no. Before exiting the vehicle, always ensure that all accessories are turned off and double check that the lights are off as you walk away.


4. Keep your battery clean

Ensure the top of your battery is clean, dry, and free of dirt and grime. A dirty battery can discharge across the grime on top of the casing – creating a mild short circuit which will eventually flatten the battery.

The battery terminals will also corrode over time, and keeping them clean from buildup is a great way to extend the life of your car battery. Scrub the terminals with an old toothbrush dipped in a baking soda and water mixture. Then, using a spray bottle with cold water, rinse the mixture off and follow up with a thorough drying with a clean cloth.


5. Try to minimise heat exposure

A popular misconception is that cold weather kills car batteries – but this is not strictly true. Car batteries do have to work harder to start your engine during the winter months, but the reason why so many fail during winter is mostly due to damage they sustained during the heat of the previous summer.

Extreme heat is hard on batteries because it increases the rate of water evaporation from the cells – even in sealed top batteries. The cold then reveals the shortcomings of the weaker battery, as lower temperatures sap the remaining cranking power as it tries to start cold engines with thick oil.

So what can you do? Well, basically anything you can think of to reduce the temperature subjected to the battery. Parking your vehicle in the shade where possible and keeping your vehicle garaged while not in use are both great ideas – or you can look at ways to help insulate the battery from heat generated within the engine bay.


6. Check your battery’s voltage once a month

A lead-acid battery’s life will shorten dramatically the longer it is left partially or fully discharged, so checking the voltage with a voltmeter once a month is a great way to keep an eye on your battery’s health. A healthy, fully charged lead-acid battery should have a voltage of around 12.7 volts or above.

Should the voltage drop below 12.5 volts, we’d recommend recharging the battery as soon as possible. It is also important to remember that a lead-acid car battery is considered to be half charged at 12.4 volts, and completely flat / dead at 12.0 volts – so don’t get complacent.


7. Don’t leave the car unused for long periods

As you might have noticed in some of the points above, it is vital that lead-acid car batteries are kept fully charged at all times to prevent damage. Regardless of the brand, all lead-acid batteries will naturally lose charge over time – something which is referred to as ‘self-discharge’.

A flooded lead-acid battery will self discharge at a rate of around 1% per day at room temperature, 0.25% per day at 10°C (50°F) and 1.5% per day at 30°C (86°F). It is important to remember that parasitic loads from the vehicle will increase the rate of discharge, so if your vehicle is going to be sitting unused for any longer than a week it would be advisable to connect a trickle charger to keep the battery in tip-top condition.

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