Why car batteries die in cold weather – and how to prevent issues

As soon as the cold weather sets it, we see batteries going bad everywhere. Why do car batteries seem to go bad or die in the winter? It’s actually nothing abnormal, it’s just the way things work.

We can narrow down a weak or dead battery in the cold because of 5 reasons

1. Battery Chemistry: Car batteries are typically lead-acid batteries. In cold temperatures, the chemical reactions that produce electricity are slower. This means that the battery can’t deliver as much current as it could at warmer temperatures.
2. Thicker Engine Oil: In cold weather, motor oil becomes thicker, which makes the engine harder to crank. As a result, the starter motor requires more current from the battery to turn the engine over.
3. Reduced Capacity: Batteries have a capacity rating, usually in ampere-hours (Ah). In cold weather, the actual capacity of the battery can decrease. That is, even a fully charged battery might act like it’s only partially charged when it’s cold.
4. Parasitic Drains: Many modern cars have various electronic accessories and computer systems that draw power even when the car is off. These drains, although small, can add up if the car isn’t driven for extended periods, especially in the cold.
5. Age of the Battery: Cold weather can be the final nail in the coffin for an aging battery. If the battery was already weak or nearing the end of its life, cold temperatures can push it over the edge.

But all is not lost!

Here’s how you can prevent cold weather battery failures

1. Regular Checks: Make sure to have your battery tested before winter starts, especially if it’s over three years old. Mechanics can assess the health of the battery and tell you if it’s likely to fail soon.
2. Keep It Charged: If you won’t be driving your car for an extended period, consider using a battery maintainer or trickle charger. These devices keep your battery topped up and can help prevent the gradual discharge that can happen over time.
3. Park Indoors When Possible: Keeping your car in a garage, even if it’s unheated, can help keep it warmer than if it were outside exposed to the elements.
4. Insulation: Some people use battery blankets or wraps. These can keep the battery warmer, slowing the loss of capacity due to cold.
5. Check for Parasitic Drains: If your car is draining the battery faster than expected, there might be a parasitic draw somewhere in the system. This could be due to a faulty relay, a malfunctioning accessory, or other issues. A mechanic can help identify and rectify this.
6. Good Connections: Ensure that the battery terminals are clean and tight. Corrosion or loose connections can impede the flow of electricity and make it harder for your car to start.
7. Use the Right Oil: During winter, using the correct grade of engine oil recommended for colder temperatures can make the engine easier to crank.
8. Consider an Upgrade: If you live in an area with particularly harsh winters and have repeated issues, you might consider upgrading to a battery with a higher cold cranking amps (CCA) rating, which indicates the battery’s ability to start an engine in cold temperatures.

In the end

We can avoid problems with a little care. Because testing the battery is so easy, I urge you to at least test it yourself using a multimeter or just go to a shop to get it tested.

And if you know you live in a harsh winter area, I can vouch for a proper battery insulaton wrap or whatever you call them – most auto parts & accessories store have them or just go to Amazon.

Cold weather is when I especially look out after my car. There’s nothing worse than breaking down in cold weather. Everything is harder to do. So take care!