Extreme cold dramatically reduces the speed at which chemical reaction can occur, while increasing electrolyte resistance. It is important to keep batteries at a full charge during periods of extreme cold. Batteries in a discharged state are susceptible to freezing, which can cause damage to the plates and battery container. Automobiles demand more from a battery in freezing temperatures as the motor oil thickens and makes the engine harder to crank.

Cranking amps are the numbers of amperes a lead-acid battery at 32 degrees F (0 degrees C) can deliver for 30 seconds and maintain at least 1.2 volts per cell (7.2 volts for a 12 volt battery). In other words, CA/cranking amps determine how much power you have to start your car in most climates. The basic job of a battery is to start an engine; it must crank, or rotate the crankshaft while at the same time maintain sufficient voltage to activate the ignition system until the engine fires and maintains rotation. This requirement involves a high discharge rate in amperes for a short period of time. Since it is more difficult for a battery to deliver power when it is cold, and since the engine requires more power to turn over when it is cold, the Cold Cranking rating is defined as: The number of amperes a lead-acid battery at 0 degrees F (-17.8 degrees C) can deliver for 30 seconds and maintain at least 1.2 volts per cell (7.2 volts for a 12-volt battery). In other words, CCA/cold cranking amps determine how much power you have to start your car on cold winter mornings.