1. How does a battery work?

A battery works by storing electrical energy from the alternator as chemical energy. This chemical energy is reconverted on-demand from the electrical system.

It develops voltage from the chemical reaction produced when two dissimilar metals such as the positive and negative plates, are immersed in the electrolyte (a solution of sulphuric acid and water). In a typical starter battery, the voltage is approximately 2 volts per cell, for a total of 12 volts. Electricity flows from the battery as soon as there is a circuit between the positive and negative terminals. This happens when any load that needs electricity such as a radio, immobiliser or alarm is connected to a battery.

Most people don’t realise that a lead acid battery operates in a constant process of charge and discharge. When a battery is connected to a load that needs electricity, such as the starter in your car, current flows from the battery and it begins to be discharged.

A battery becomes charged when current flows back into it, restoring the chemical difference between the plates. This happens when you are driving without any accessories and the alternator puts current back into the battery.

As a battery discharges, the lead plates become more chemically alike, the acid becomes weaker and the voltage drops. Eventually the battery is so discharged that it can no longer deliver electricity at a useful voltage. You can recharge a discharged battery by feeding electrical current back into the battery. A full charge restores the chemical difference between the plates and leaves the battery ready to deliver its full power.

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2. What are the most common causes of battery failure?


  • Positive grid corrosion. (This is a natural occurrence over time, however it is accelerated by operating in an extremely hot climate or by overcharging. Overcharging can occur due to malfunction on the part of your vehicle’s electrical system.)
  • Loss of electrolyte due to heat or overcharging
  • Sulphation in storage
  • Undercharging with voltages less than 13.8 volts
  • Old age
  • Corrosion
  • Physical damage due to vibration
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3. Can a battery really explode?

Yes, so when working with or near a battery, or jump starting a vehicle, always:

  • Wear glasses or safety goggles
  • Shield eyes and face from the battery
  • Keep as much distance as possible from the battery
  • Read warning labels on the battery
  • Do not cause any flames or sparks
  • Read the vehicle instruction manual before jump starting

If you should get acid on your skin or in your eyes, flush with water immediately and seek medical attention.

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4. What sort of maintenance should I perform on my battery?

Modern automotive and light truck batteries need little attention. Check the battery once a year for signs of corrosion at the terminals. Clean the terminals with a mixture of baking soda and water. Keep the top of the battery clean of heavy dirt and oil to prevent low grade short-circuiting.

Some batteries are equipped with removable vents so the electrolyte levels in each cell can be checked and filled with water if the level is low. Always use good quality drinking water or distilled water to prevent iron or other chemicals from contaminating the electrolyte. Be careful not to overfill the cells or acid may be expelled during operation or charging. If your vehicle has not been started in more than a month, recharge the battery before using the car.

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5. How do I know when to replace my battery?

Here are some warning signals that may indicate a problem with your battery or your charging system:

  • Your starter motor is experiencing slow or interrupted turnover
  • Your battery seems to lose power quickly in cold weather
  • Your headlights dim when idling
  • The battery/charging system warning light on your instrument panel stays on for extended periods after the engine is running

To determine if the battery is failing, have your battery tested for free at your nearest Exide outlet.

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6. How long can I leave my battery unused?

Lack of use is one of the greatest enemies of a battery, especially an automotive battery which is designed to be charged regularly by an alternator. Any unused battery, regardless of its chemistry, will self discharge over time and if allowed to remain discharged, will undergo severe positive grid corrosion and premature battery failure. The rate of discharge will depend on the type of battery and the storage temperature.

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7. What is the difference between a car battery and a leisure battery?

A car’s battery is designed to provide a very large amount of current for a short period of time – known as micro-cycling (except for stop/start vehicles). This surge of current is needed to turn the engine over during starting. Once the engine starts, the alternator provides all the power that the car needs. Used in this way a car battery can last a number of years. To provide a large amount of starting current, a car battery uses thin plates in order to increase the plate surface area.

A leisure battery is designed to provide a steady amount of current over a long period of time. It can provide a surge when needed but less than a car battery can. Leisure batteries are also designed to be discharged over and over again (something that would ruin a car battery very quickly). To accomplish this, leisure batteries sometimes use thicker plates and glass mat separators are added to increase the life of the positive plates.

The purpose of a leisure battery is to provide power for trolling motors, uninterrupted power supplies (UPS) and other accessories for marine, recreational vehicle (RV), commercial and stationary applications.

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8. How do I recharge a leisure battery?

The leisure batteries are charged at a current equivalent to 0.1 times the capacity expressed in Ampere hours (Ah) for a maximum of 13 hours. While 12 to 13 hours would normally be sufficient with a constant current charger, 15 hours may be necessary with a taper charger.

The exact duration of the recharge required will depend on the extent of the discharge that the battery has experienced. As an example a 50 Ah type RR1 battery that has been utilised for 3 hours for lighting a 100W lamp would have consumed 25 Ah and therefore must be charged at 5 Ampere for approximately 6 hours.

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9. How can I avoid battery problems?


  • Ensure the vehicle charging system is in order
  • Ensure battery terminals are free of corrosion and are tightly fitted
  • Ensure the battery is held in place in the vehicle and that it is not loose
  • Ensure your battery is the right capacity for your vehicle
  • Make sure there are no short circuits or continuous drains of current (such as an alarm or immobiliser) over long periods without the battery being charged
  • Avoid using jumper cables, as this is likely to damage the battery terminals
  • Periodically ensure the battery is fully charged by measuring the specific gravity of the electrolyte
  • Perform regular battery checks
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10. What battery recycling process does First National Battery follow?


  1. Batteries are collected through Battery Centre franchises and other sources around the country.
  2. Scrap batteries are transported to the smelter in Benoni.
  3. Batteries are processed through a battery breaker, separating lead, plastic and acid.
  4. The acid is neutralised and processed through the effluent plant before being disposed of in accordance with environmental regulations.
  5. The plastic components are washed and converted into pellets to be re-used in the manufacturing of new battery containers and covers by First National Battery.
  6. The battery plates, terminals and other lead pieces are stockpiled for refining and blending with other materials to produce lead alloys for new batteries.
  7. Any elements of the scrap batteries that can’t be reclaimed are disposed of in a compressed cake form in a Class 1 dump.
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