At the point you turn your ignition key, a battery must provide a considerably high current for a short time, for example,
lasting as much as 300 amps for only 15 seconds.

This process was designed to start a motor only once. The battery does not keep a car running, it’s the alternator that does that,
generating the electricity required to keep the engine going and enabling other operating devices.

The starter’s job is finished once the car starts, and is dormant until the car needs starting again. The battery, after providing the
current needed to start the car, is also needed to absorb sudden drops or surges in voltage. These are called voltage spikes. A minus 200 volt spike can occur once the car is started, then at other times large positive and negative spikes can occur. This fluctuation of electricity must go somewhere, so the battery acts as a buffer and soaks it up, basically shielding the car’s electrical system from damage.

How to Maintain a Car Battery

Most modern car batteries have a life expectancy of between 4 and 7 years. During this time you will need to maintain the car battery to keep it in good condition and maximise its service-life.

There are two types of car battery available in today's market; the sealed type and standard type. Sealed car batteries need very little maintenance and may only need their connections checked for corrosion bi-annually.
Standard type batteries however need a little more attention. With removable caps, each battery cell can be checked and topped up with de-ionised water as required. It is a good idea to check these levels annually.

Basic Car Battery Maintenance

1) Check the condition of the car battery terminals and clamps. If corroded, these will need cleaning with a solution of baking soda and water. Let the solution finish bubbling and wipe off with a wet cloth. Once the battery terminals are clean apply grease to prevent future corrosion.

2) Check the levels of the car battery electrolyte. If low, they will need topping up with de-ionised water. Remove caps, check each cell individually and fill to the battery's max line. Once all levels are at the max line, replace caps.