The basic job of a battery is to start an engine; it must crank (rotate the crankshaft) via the starter motor and supply sufficient voltage to activate the ignition system until the engine starts.This requirement involves a high discharge rate in amperes for a short period of time.Cranking amps are the number of amperes a lead-acid battery at 32 degrees F can deliver for 30 seconds and maintain at least 1.2 volts per cell (7.2 volts for a 12 volt battery).Since it is more difficult for a battery to deliver power when it is cold and the engine requires more power to turn over, the Cold Cranking rating is defined as the number of amperes a lead battery at zero degrees F can deliver.CCA/cold cranking amps determine how much voltage you have to start your vehicle in cold conditions.Batteries require electrolyte and full charge prior to installation