Cold cranking amps or CCA is the maximum amount of amps that a battery can provide for 30 seconds at zero F. Two of the most important things to consider when choosing the right battery are cold cranking amps and reserve capacity, according to CarsDirect.
The battery must be able to provide enough power to the starter motor so that the starter is able to turn the engine over in order to start. Cold weather means the engine may have a harder time turning, and the chemical reaction for the battery to make power is less efficient in cold weather. Battery power is also needed for the ignition system to produce a hot enough spark to cause ignition. The battery also has to power the fuel pump to send the gas to the injectors, which also need electricity from the battery to inject fuel. With newer cars introducing all new types of technology into them, there is a need for batteries to have a high CCA. Most batteries are designed to produce CCA ratings anywhere from 400 for smaller batteries and sometimes more than 1,500 for larger batteries.
A reserve capacity rating is also important, because it is the amount of time that a battery can maintain a 25-amp discharge and still have enough power to be used again. This is an important consideration if the battery is going to be used when the vehicle is not running and charging the battery.
It is important to know how much power is needed in any situation that comes up — whether it's letting the radio play with the engine off before starting the engine or trying to start the engine in cold weather.