AH (Ampere Hour)
An ampere hour (abbreviated Ah, or sometimes amp hour) is the amount of energy charge in a battery that will allow one ampere of current to flow for one hour. An ampere is a unit of measure of the rate of electron flow or current in an electrical conductor.
CCA (Cold Cranking Amps)
CCA is a rating used in the battery industry to define a battery’s ability to start an engine in cold temperatures. Generally speaking, it is easier to start an engine in a warm environment than in a cold one. The rating refers to the number of amps a 12-volt battery can deliver at 0°F for 30 seconds while maintaining a voltage of at least 7.2 volts. The higher the CCA rating, the greater the starting power of the battery.
If you own a relatively older car, it is recommended to use a higher AH battery than what is mentioned in the owner’s manual. Older engines sometimes need slightly more power to crank than the new ones.