It is pretty common for car batteries to die in the winter. Therefore, it is a good idea to check your battery and perform regular maintenance in the fall so you won’t be left stranded in the cold.
Lead-acid batteries are made to work well in a wide range of temperatures, but performance suffers in cold environments. The capacity of lead-acid batteries drops as much as 20% when temperatures are freezing. When the temperatures sink to -22 degrees Fahrenheit the capacity decreases by as much as 50%. In addition to reduced capacity, an increased draw from accessories and starter motors can also cause a car battery to die in the winter.
Higher Demands of the Starter Motor
When you start a car, it takes a considerable amount of amperage to get the starter motor going. Normally, this is no problem for the battery. After all, delivering amperage quickly is one of the things lead-acid batteries do best.
An older car battery is going to have a difficult time in the cold temperatures of winter. Regardless of age, when the temperature is at or below freezing, the capacity of the battery is reduced so much that it is not able to handle the demand the starter puts on it.
If you have ever looked at the vital statistics of a battery, you have probably noticed something called Cold-Cranking Amps, or CCA. This number refers to the amount of amperage the battery is able to put out when it is cold. A larger number means the battery will be able to meet higher demands. This means that in the winter when the capacity is reduced, it will perform better than a battery with lower cold-cranking amps.
Sometimes, especially when the weather is very cold, the amperage demands of the starter motor will be higher than normal. This only adds to the problem. When the weather is so cold, the motor oil becomes thick. This is especially true if you are using a single-weight oil that does not feature different viscosity ratings for hot and cold weather. When the oil is thick, it is more difficult to turn the engine over. Therefore, the starter motor will require a greater amount of amperage.
Higher Demands of Accessories
Typically, driving during the winter months is going to increase the strain on a car battery. The reason for this is the increased demand for accessories such as windshield wipers and headlights, which are often used more during the shorter days and inclement weather that comes with wintertime.
Without a high-performance alternator, the charging system can struggle to keep up with the increased demand. Because the battery is already suffering due to the reduced capacity in colder temperatures, this can speed up the death of an older car battery.
How to Help Your Car Battery Survive Winter
Whenever a car battery is operated beyond the optimum range of temperature, there is an increased chance of failure. One way to prevent failure is to keep your car battery charged. A weak battery is much more likely to freeze than a battery that is fully charged. Before winter, be sure to have your battery tested to ensure that it is prepared to survive.