Cold weather reduces the electrical charge in a battery but increases the amount of electrical draw needed to start a vehicle, which makes the amount of cold cranking amps available critical for starting a car. Different vehicles have varying requirements for cold cranking amps. Typically, larger and older engines require more power to start.
The chemical reaction between the sulfuric acid electrolyte and the lead-oxide plates in a battery is what allows it to take and keep an electrical charge. This chemical reaction slows as the temperature drops, which impedes its ability to maintain a charge. Cars that are operated in colder climates need batteries with more cold cranking amps.
As a vehicle gets colder, the fluids inside of it, such as oil, transmission fluid and coolant, get thicker. This increases the amount of friction and the force needed to turn the motor. The starter then requires more power to get the engine moving. Larger engine sizes increase this demand because they typically have larger and heavier moving parts. Newer engines are engineered for efficiency through the use of lighter weight, higher performance materials that have reduced the overall operating friction and cold cranking amp requirements.
Manufacturers generate more cold cranking amps by increasing the amount of surface area on the battery's internal plates. This is often achieved by increasing the number of plates, drilling holes in the plates or incorporating waffles or ribs in the plate design.