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Car Batteries – Your Questions Answered

  • Batteries-Tips/Guides

Automotive batteries are relatively simple components of a car. They have a number of functions, for instance: 1) To supply a burst of power to the starter when you turn the key. 2) To supply power to the electrical system when the engine is switched off. 3). Keep the car running long enough in the event that the alternator should fail.

Yet, there are also many complexities that, as a car owner, it helps to understand and keep informed about – which can save you time and money in maintenance and replacement costs. Let’s take a look at some frequently asked questions that motorists have about the batteries that power up their vehicles:

How does a car battery work?

Most passenger cars use lead-acid batteries which consist of metal plates surrounded by sulphuric acid housed in a plastic casing. The chemical energy is converted into electrical energy which starts the car when the ignition is turned.

Do I need to top up my car battery with water?

Some batteries need occasional maintenance by topping up with distilled water to ensure the electrolyte solution is properly mixed. However, the vast majority of newer car batteries are now classified as maintenance-free. While some may have removable caps in order to check water levels, most of these types of battery cases are designed to be sealed and in both cases never require you to top up. 

Is there such a thing as a maintenance-free battery?

Yes, most batteries nowadays do not require the maintenance that older batteries used to. However, this doesn’t mean you can ignore it. Ensure that the leads are free of corrosion, the cables are in good condition, and that the battery is sitting properly in its housing and the nuts are securely fastened.

How can I tell the age of my battery?

Check the label, typically on the side of the battery casing to determine the age of your battery. There should be an alphabet A - V, each indicating a month of the year from January to December. The digit following the letter indicates the year of manufacture.

Can I leave my battery unused for an extended period of time?

Avoid letting batteries go unused as they will self-discharge over time and if allowed to remain discharged, could suffer permanent failure. How quickly discharge occurs depends on the type of battery and the temperature it has been stored at.

How long does it take to recharge a battery?

Logically, the weaker a battery, the longer it will take to recharge. As a rule of thumb, a battery that has been badly depleted could take up to 12 hours to recharge, depending on the strength of the charger.

Can I use another car’s battery to recharge a weak battery?

No. A car battery does not contain enough voltage to kick-start the chemical reaction needed for a depleted battery to start recharging.

Will driving the car recharge my battery?

The extent of the alternator's ability to adequately recharge the battery while you're driving depends on the battery's age, temperature, how long you drive, and how much current is sent from the alternator to the battery.

Can car batteries be overcharged?

Yes, overcharging a battery will cause it to overheat and damage it. The hotter it becomes, the more current it will accept, resulting in thermal runaway. This can very rapidly destroy a battery’s life.

Warning: Overcharging can cause an explosion. 

Can a car battery explode?

Most car battery explosions are caused by thermal runaway, which occurs when the battery overheats. Older lead-acid car batteries are more susceptible to the effects of thermal runaway. 

Another reason a battery is at risk of an explosion is age. As it becomes old, it loses water and the lead plates in the battery begin to warp. Upon ignition, the warped plates flex and touch one another, which can lead to a sudden explosion.

How long should a car battery last?

A conventional lead-acid car battery’s lifespan is on average about four to five years. However, a battery’s life can be reduced due to high temperatures or hot climates, if it’s frequently run down, undercharged, or if the car is regularly driven on rough roads.

How should I preserve a car battery while the car is in storage?

Disconnect the battery if the car is in storage for an extended period. Connect the battery to a battery maintainer or charge it every few months. Battery tenders or maintainers can extend your car battery's life and eliminate the need for a charger altogether when you use them regularly.

What is a car battery warranty?

A warranty does not indicate battery performance, but is instead cover from the manufacturer on material and workmanship defects for a set period. It stipulates the replacement of the faulty battery and the warranty begins on the date of the original purchase.

How should I dispose of my old car battery?

Car batteries  must always be recycled as they contain acid and lead, which is a toxic heavy metal. Never throw your used car battery into your everyday recycling bin or trash can. Most battery centres will accept your old battery for recycling.

Which parts of lead-acid batteries can be recycled?

A lead-acid battery comprises of 100% recyclable materials, such as the lead, the plastic, and in some cases, even the electrolyte.


As vehicles become more sophisticated, batteries are required to deliver more and must power more electronic items such as cellular phones and on-board computers that continue to draw power even after you’ve switched off the motor.  With the help of these commonly asked questions you should be able to avoid common battery problems.

As an extra tip, don’t forget that whenever replacing a car battery it must be the right capacity for your vehicle. If it’s time for a battery replacement for your car, visit your nearest Supa Quick fitment centre where we stock both premium and more affordable batteries to suit your pocket.

Also read:

  • 4 Common Types of Lead-Acid Batteries for Cars
  • Experience the Power of the All New Supa Power Battery
  • 5 Good Reasons to Recycle Your Car Battery
  • 14 Car Battery Myths You Need to Know
  • Car Battery Hazards You Need to Know
  • How To Choose the Right Battery for Your Car – 6 Key Factors to Consider 

Disclaimer: This information is for educational, or entertainment purposes only. It must not be construed as advice, legal, financial, or otherwise. We do not make any warranties about the completeness, reliability, and accuracy of this information.


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