Car battery CCA, or cold cranking amps, is a car battery rating that measures how effective it is at starting vehicles in cold weather conditions. The power output of a battery significantly decreases with temperature; at 35 degrees Fahrenheit, capacity drops 35 percent, and at 0 degrees Fahrenheit, it drops another 60 percent. The CCA rating system was developed to let consumers know how well a battery will work in cold temperatures.
The CCA of a car battery is measured by how much current the battery can output at 0 degrees Fahrenheit. A battery’s cold cranking amperage is the number of amps it can output for a full 30 seconds while maintaining at least 7.2 volts at that temperature.
Batteries with a high CCA rating generally cost more than lower CCA batteries, so the kind of CCA you want is determined by the temperatures in which you usually start the car. If you live in a cold climate, invest in a high CCA battery; if you live in a warm region, it may not be worth the extra cost. Some people who live in climates with cold winters and moderate summers prefer to buy a small battery with a high CCA rating for winter, and another car battery for summer. That way they can save the high CCA battery for the times when they need it most, in order to make it last longer.