When you turn the key to start your car, the battery supplies power to the starter motor, which turns the engine over. At the same time, power from the battery is supplied to the spark plugs in order to ignite the fuel and air mixture that has been compressed in the engine combustion cylinders.
The battery power used during the starting up process is then replaced by the alternator, which supplies the bulk of electrical current to your car's electrical systems, keeping your battery fully charged.
The battery strength or cranking amp is generally affected by the amount of work it does and the conditions in which it has to work. The growth of in-car technology such as air conditioning, digital music players, satellite navigation systems and other electronic gadgetry are placing greater strain on your car's battery. All of these increase the demand on your car's battery and charging system which can lead to premature battery failure. Consequently, more frequent checks are recommended so that your car battery maintains its optimum working level.
Regular battery checks can help identify and prevent premature battery failure, which can result in a vehicle breakdown at the most inconvenient time.