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14 Car Battery Myths You Need to Know

  • Batteries-Tips/Guides

Out of the many components that make a vehicle function, the battery is one of the parts that we are familiar with. We know it has positive and negative terminals, starts the car, and makes the radio and lights go on. In fact, we may tend to think of a battery as a fairly simple component, unlike an engine or exhaust system, for instance.

Car with open bonnet

Yet, there are many misconceptions about car batteries, and these myths can shorten its life, damage it entirely, and even cause damage to other components in your car. It’s time to dispel them with some facts:

1. If your car won’t start, it’s always the battery’s fault

A flat or dying battery, or corrosion on the battery’s terminals is a common cause of your car failing to start, but other causes should be considered, such as a faulty starter motor/alternator, clogged fuel injectors, or worn spark plugs.

2. There’s no harm done by jump-starting a flat battery

A jump-start will help to revive a flat battery, however this puts strain on the alternator which has to work harder to provide enough energy to keep the battery charged.

3. Driving a car will help to recharge a weak battery

Simply driving your car for any period of time will not fully recharge the battery because just starting it up puts a massive strain on the battery. A short drive is just not worth the amount of energy needed to crank up the car’s engine, and continuous undercharging will shorten its lifespan .

To reliably restore a flat battery’s charge, use an appropriate multi-stage battery charger.&nbsp

4. Letting a car idle will recharge a weak battery

Simply sitting and letting your car idle for any period of time will not fully recharge the battery and may even shorten its life. A better option is to connect a maintenance charger to keep your battery in good condition.

5. A flat car battery doesn’t affect fuel economy

A flat battery causes the alternator to work harder, adding extra load to your engine which in turn uses more fuel.

6. A car battery has a defined lifespan

How long your battery will last is determined by how fresh it was at the time of installation, the installation itself, and other factors like how often you drive the car and maintained the battery.

7. A battery can last the lifetime of a car if well-maintained

In contrast to the above myth, some people think their batteries can last virtually ‘forever’.  But batteries, like all hard-working vehicle components wear with use and age.

8. Disconnecting the battery if I won't be driving it for an extended period is a good idea

If you have a more modern vehicle that comes with on-board computers that run the electrics, steering, transmission and security systems, disconnecting the battery may cause you to lose its computerised settings. It’s possible too that they’ll no longer work properly even after reconnecting the battery. Instead, use a maintenance charger.

9. Maintenance-free batteries never need to be checked

All vehicle batteries need regular checks and maintenance, which includes cleaning the terminals of corrosive build-up and to ensure that it is fitting securely in its housing.

10. The battery warning light on the dashboard means the battery is faulty

Not necessarily, as this could also indicate a problem with the alternator or the car’s charging system. This means that the car is then only running on battery power. Continuing to drive this way will cause damage to the electrical system and the car will eventually break down.

11. A car battery can be used to run a caravan fridge/boat/etc.

Doing this will only ruin the battery. A car battery is designed to produce a large amount of current over a very short period of time to start a vehicle. A fridge battery is designed to produce a small amount of power over a long period of time. A boat battery is designed to handle conditions over water and other features. Always use the correct battery that is intended for its purpose.

12. Car batteries last longer in hot climates than in cold

In extreme cold it can be difficult to start a car because the battery struggles to crank up power, but it’s high temperatures that limit its lifespan. The liquid electrolyte solution in car batteries is what holds a battery’s charge. In extremely hot temperatures, this liquid evaporates faster, which can reduce its performance and longevity.

13. Batteries discharge faster in winter

The optimal outside temperature for a battery is around 20°C. But when temperatures climb higher, the battery will naturally self-discharge causing it to age faster. This process lowers the stored charge that the battery should have, and may only become noticeable in winter when the engine requires more energy to start.

14. You can test the quality of a battery by its weight

While it’s true that the more lead a battery contains the better the quality, a lesser-known, low-quality, cheaper battery may contain ‘dead weight’ – and not lead – that makes it heavy.

Obviously, in the case of lithium ion batteries used in electric vehicles, this weight equals quality rule doesn’t apply.


A little knowledge goes a long way and can save you heaps of cash, especially when it comes to high-value items like your car. To be sure you’re getting a quality battery replacement expertly installed, visit a Supa Quick fitment centre before you go on your next road trip. Because peace of mind means better driving style.

Disclaimer: This content is for informational, educational, or entertainment purposes only. We do not make any warranties about the completeness, reliability, and accuracy of the content.


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