Function

• The battery is a part of the car's charging and starting system. The battery stores energy in chemical form and releases it as electricity when you turn the key in the car's ignition. This electrical power cranks the car's engine and releases energy to power the car's lights and other accessories. Also, the alternator directs electrical energy back to the battery, recharging in preparation for the next start.
  
  

Voltage and Cold Crank Amps

• The batteries in modern cars have a standard of 12 volts. The battery is considered charged at 12.4 volts, and considered to be fully charged at 12.6 volts. Also, as the temperature outside decreases, the cranking power required of the battery increases. Therefore, in colder climates, batteries with a higher cold cranking amps rating, CCA rating, are needed.
  
  

Types

• One particular battery will not work with every car. The wrong size battery may not fit securely in a particular car or may not provide the proper amount of power to start the car. Batteries have either top terminals or side terminals, which a specific car's cables may or may not reach.