what is CCA ?

Cold Cranking Amps. This is a measure of the maximum output current that can be obtained from the battery which is limited by the battery's internal resistance. In general, higher CCA is better, but the other measures of a battery are the energy it stores (usually measured in amp-hours) and the reserve time. Many times a battery manufacturer will sacrifice one of these at the expense of the other. The actual CCA you require is dependent upon the vehicle (4 cylinders are easier to turn over compared to 8 cylinders) and the climate where the vehicle is driven (colder means heavier oil and more power to turn the starter so draws more current).

Bob