The most common reasons why car batteries die

The most common reasons why car batteries die

There’s nothing worse than getting in the car, putting the key in the ignition and nothing. A big. Fat. Nothing. Typically this happens when you’re running late for work, the kids need to catch a bus or train at a particular time for an important event or it’s bucketing down rain and you’re in the middle of nowhere! Either way, there’s few things more frustrating than having a dead battery in your car. 

In the following article we explore all the reasons your battery might be dead or why your battery might be being drained unnecessarily and what you can do about it. 

You messed up

We’ve all been there. A long day at work, you’re more tired than usual or you’re just having an off day and you leave the vehicle lights on. This is one of the most common reasons batteries die. 

Many newer cars will have an audible alarm if you leave the lights on but every now and then you might just leave the parking lights on, or an internal light or even the radio. Often human error is the major reason for batteries to be drained unnecessarily and unfortunately, there’s not much we can do about this except create better habits. 

When exiting your car, make sure none of the following are turned on:-

  • Headlights
  • Interior lights
  • Indicators
  • Radio 

Handy Hint - If you have a bad habit of leaving lights on in the car, create a list of things you need to check every time you leave the vehicle and don’t take your seatbelt off until you’ve gone through your entire list. 

Faulty charging issue or defective alternator

Many people think your car's lights, radio, etc run directly off the car battery and this isn’t technically the case. In your car is an alternator which acts as a generator to distribute electricity to your car whilst driving along with recharging your car battery. An alternator essentially turns mechanical energy into electricity for use in your car (it’s the same concept as a wind up torch where a series of magnets and copper wiring spin to create electricity).

If your alternator is faulty, instead of producing electricity to power your lights, radio and recharge your car battery, this power will be pulled from the battery itself, hence draining your battery. 

Large number of short drives

The highest drain on your battery is when you start your car. If you start your car and don’t give the alternator enough time to charge the battery again, the battery will drain pretty quickly over time. If you’re going through batteries in your car regularly or they seem to drain really quickly and you’re only ever ‘popping down to the shops’ or driving a very short distance, this is likely the case. 

Handy Hint - If you only use your car for short distances, let your car idle for a few minutes before leaving your home if it’s safe to do so (please do not let your car idle unattended in your driveway) take a longer route to your destination or look at purchasing a battery charger. 

Leaving your car in storage for a long time

Even when your car is off, there are still electrical items in your car drawing current. Your car’s clock or alarm system will still draw power and run down your battery over time.

Handy Hint - If you aren’t using your car for extended periods, it’s a good idea to start it and take it for a drive at least once a month if possible. This will give the alternator a chance to rechange the battery. 

Your battery is old

Like most things in the universe, batteries are subject to the second law of thermodynamics, entropy. This means that over time, batteries will store less and less charge from the alternator to a point where they will not hold enough charge to start your vehicle. If this happens it’s time to replace your battery. 

Handy Hint - If you need to replace your car battery, talk to us today!

Extreme heat or cold

Like the rest of us, batteries are prone to not work as well in extreme weather conditions. If you’re in areas where there is prolonged cold or heat, this can have an effect on the condition of your battery and even cause it to stop working altogether. 

At zero degrees batteries will become considerably weaker (up to 35%) and it just goes downhill from there. Luckily here in Queensland we don’t need to worry about those types of temperatures all that often. The opposite is also true. If your battery is in extended heat for long periods of time, this can make it ‘parched’ and vital liquids can evaporate and weaken the charge. 

Handy Hint - If your car needs to be parked in extreme heat for extended periods of time, make sure to start it and go for a drive regularly. 

If you’ve read through this article and you’re still not sure why your car battery is giving you grief, talk to the battery experts and call Allstar Batteries on the contact details below.

We have the northside of Brisbane covered when it comes to your battery requirements so drop into one of our main stores at Brendale, Caboolture or North Lakes.


12 Garret Street
Brendale Qld 4500
Ph: 0413 692 236


6/106 Lear Jet Drive
Caboolture Qld 4510
Ph: (07) 5309 4905


12/88 Flinders Pde
North Lakes Qld 4509
Ph: (07) 3048 2293


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