Why do car batteries die in winter? It always seems to happen at the worst possible time. The snow is falling, the thermometer has dropped to below zero, and you need to get to work. You open your car door and step inside. You turn the key and hear – nothing.
Your battery has died, and it happened on the coldest day of the year. Is it just bad luck, or is there a reason that automotive batteries die in the winter months?
Car Batteries – Failure Can Happen At Any Time
It is important to point out that battery failure can happen at any time of year. Whether the temperature is warm and wonderful or cold and blustery, the battery in your vehicle has a limited lifespan. If your five-year battery is nearing the end of its expected life, it is only a matter of time before its starting power begins to fade. That is why it is important to check the date on your battery and have it tested and possibly replaced before it is too late.
Even so, there are factors that make the battery in your vehicle more likely to give out, including the outside temperature and weather conditions. The lead-acid batteries most commonly used are surrounded by a plastic case housing several lead plates in an electrolyte pool. That electrolyte mixture is made up of sulfuric acid and water.
Each time the battery does its job, a chemical reaction is created, and over time the positive and negative plates inside the battery become coated with a compound known as lead sulfate. This process, described as sulfation, is what reduces the battery’s ability to hold a charge. Over time, the effects of that sulfation add up, eventually resulting in a dead battery.
When the weather gets colder, your battery has to work harder to start your vehicle, which can exacerbate the effect of the chemical reaction and the resulting sulfation. That is one of the reasons car batteries tend to die more readily in the winter months, leaving you stranded by the side of the road – or in your own driveway.
Watch Out for the Warning Signs
You may not be able to make the weather warmer or stop the snow from falling, but you can watch out for the early warning signs of a dying battery. It is rare for a battery to die all at once; in most cases, your vehicle will give you a few warning signs that the battery is not as strong as it used to be.
The color of your headlights is a good indication of the strength of your battery, so take a look before you pull out of the garage. If your headlights appear yellow instead of white, your battery may be losing its charge.
You should also expect a discharged battery if your electronic devices fail, if the engine cranks more slowly than usual or if the car horn sounds funny. If you have any doubts about your battery’s power, you should have it checked by a professional – before the cold of winter sets in.