A device that stores the electrical energy as chemical energy and supplies this energy as electrical energy when needed is called battery.

  • It provides the required amount of electrical energy to operate the starter engine and start up the vehicle.
  • Furthermore, it meets electric power demand of the ignition sytem to start up the vehicle.
  • In the cases when the alternator does not meet the demand in an automobile, it also supplies power to the other components of the system such as starting ignition, head lamps, heaters, air condition and radio that require energy to operate.
  • Besides, it protects the computer memories, head lamps and radio against the electrical fluctuations by forming the whole voltage control system of the vehicle.

The battery selected may have a higher or lower capacity than the required.
A) If the battery is not adequate for the vehicle’s power consumption,

  1. In the event that the consumers draw excessive current, long-term high current supply may lead to high charging in the battery since this will cause the battery to be discharged quickly.
  2. Excessive amount of consumption will cause the starter to failing to start especially in cold weather.

B) If the battery’s capacity is higher than needed for the vehicle,

  1. This is depending on the alternator. The alternator would not be able to charge as required.
  2. If the cable section is too thin in the electrical cable system of the vehicle, the cable heats up and it may even cause fire in the case of the alternator feeds the high currents for a long time.