There are three main contributing factors that lead to batteries dying in the winter. This can be from reduced capacity, increased draw from starter motors, or increased draw from accessories. In the winter you will want your vehicle to be reliable, and able to start when you need it to.
When you go to start your car, the starter motor requires a tremendous amount of amperage to get going. Under normal circumstances, your battery will have no issue. A battery’s capacity isn’t reduced by age, but temperatures that are at or below freezing can even knock the capacity of a brand new battery so low that it can’t handle the demands of the starter motor. When you look at a battery’s vital statistics, cold cranking amps (CCA) is the number that refers to how much amperage the battery can put out cold. If the number is large, that means it is equipped to handle higher demands than a battery with a lower number, which in turn means that it will perform better in cold weather, when capacity is diminished.
In some cases, especially in very cold weather, starters motor amperage demands can be even higher than normal, which can compound the problem. The issue is that motor oil gets thicker when the weather is cold. When the oil gets thick, the engine can be more difficult to turn over, which in turn can cause the starter motor to draw more amperage.
Winter driving typically also puts a higher strain on your battery, due to the demands of accessories like headlights and windshield wipers that tend to get used more often. Make sure to turn off the things you are not using, so the vehicle can use all the battery power to starting your vehicle. Then once the vehicle is warmed up, you can start to use the other accessories. Also be aware of any issue that the vehicle might have, and schedule an appointment to bring it in.