Why You're More Likely to have a Dead Battery in Cold Weather

Cold weather and car batteries can have a complex relationship. There is quite a lot of science to explain why car battery problems in cold weather routinely occur, and there are some things owners can do to prepare themselves and their vehicles when winter is coming. Let’s take a look at how car batteries work, how cold weather affects their performance, and what owners can do to avoid unpleasant surprises when a car simply won’t start in the morning.

How Car Batteries Work

Car batteries may seem a little mysterious, but their presence under the car’s hood is pretty straightforward. The main job of a battery is to start the engine. After that, the alternator takes over the task of running the vehicle’s electrical systems as long as the car is running. When the car is off, the battery provides the power and can become completely discharged relatively quickly. Traditional car batteries are lead-acid, making them inexpensive, rechargeable, and relatively light considering the level of current they offer.

The batteries in a car, like all batteries, have positive and negative electrodes. Inside, there are multiple thin plates inside each cell, which work together to create 12 volts. Lead-acid batteries are not meant to be deeply discharged, such as when the owner leaves the lights on. Repeated deep discharges will quickly take their toll on the battery, causing it to wear out much quicker than expected.

Cold Weather and Car Batteries

In parts of the country where winter weather is extremely harsh, car owners might worry that their vehicle won’t start when they need it to. So, what happens to batteries in below-freezing temperatures? The voltage the battery provides is the result of the chemical reaction happening inside the internal cells. Cold temperatures, particularly those at freezing or below, slow down that chemical reaction. The result is that the battery can use up to twice the current as normal to start the engine. The deep draw on the battery can shorten the battery life.

Getting Prepared for Winter

So, what are car owners to do in order to prepare for winter and ensure their vehicles are as reliable as they are during more temperate months?There are a couple of simple precautionary measures they can try:

  • Buying a battery that is designed to function optimally in frigid temperatures. The best car battery in cold weather has a high number of cold-cranking amps, which is one of the numbers on the label drivers can check before they buy. Cold weather car batteries are readily available in the areas of the country where freezing temps are common.
  • Checking the voltage when it starts to get cold. If the battery is only a year or two old, there is a decent chance it still has a good charge. But three years in, the battery – especially one that’s been through a couple rough winters – may be weakened. A weakened battery can start freezing at 32 degrees Fahrenheit, while a fully charged battery won’t start freezing until more than 40 below.
  • Keeping the battery in good shape. During the fall, owners can have the battery load tested to see how much power it is packing. It is also vital to keep the connections clear of corrosion and make sure the electrolyte level is where it should be.
  • Replacing the battery as a preventive measure. If car owners need to have their car start at all costs, whether they have children to get to school or live with a person who might have a medical emergency, it could be better to just replace the battery when it seems to be losing power, even if it is only a few years old. It is an inexpensive way to ensure the vehicle is ready to go no matter what the temperature, and it can be a good time to switch a traditional battery for a cold weather car battery.

Owners interested in extending the life of their car batteries or checking them in the fall in preparation for cold weather can find the guidance and knowledgeable assistance they need at Sun Auto Service. Contact the nearest Sun Auto Service center today to make an appointment with our helpful technicians.