How Cold Weather Impacts Your Battery

It’s always at the absolute worst time on a freezing night when your car just won’t start. Frustrating. So, you call roadside or try to jump your car, but do you ever wonder, what is it about winter that kills your battery? 

As we roll into the season, learn why cold temperatures can leave you with a dead battery, the signs that your battery is on its way out, and how to prevent getting stuck in a similar situation.

Cold Weather and Car Batteries

A car battery provides the power to start your car and run some accessories, but it doesn’t provide continual power (that’s the job of the alternator). The battery generates electricity using lead-acid technology to create a chemical reaction that turns it into energy. Cold weather can slow this chemical reaction. This, coupled with the fact that starting a car in the winter requires more power, puts additional stress on the battery. 

If your battery is aging and on its way out, winter weather can exacerbate problems, preventing your car from starting. But while winter weather is most likely to cause your battery to fail, it’s actually hot weather that does most of the damage, which becomes evident when the temperature drops and more power is required to get the car started.

Signs Your Battery Might Be On Its Way Out

Paying attention to your car can help you avoid a dead battery by catching the problem early and getting it replaced. Here’s what to look out for:

• Slow Crank. When you try to start your car, you can hear the starter engaging and attempting to get it started, but it takes longer than it should (based on your baseline starting experience). 
• Dim Lights. Your headlights and interior lights are dimmer than usual.
• Battery Age. If you’ve had your car battery for more than 3 to 5 years, it’s worth getting it tested. Batteries don’t last as long as you might think. 
• Needed a Jump. Check your battery after jump-starting your car to ensure a bad battery wasn’t the root cause.
• Leaking or Swollen Battery. If your battery leaks acid, you’ll see a green or blue powdery substance on the terminals. Leaking or a swollen battery can often indicate your battery is near failure. 
• Battery Light. A battery light doesn’t usually mean you need (just) a battery, but if it goes on, your battery might have been fatally damaged by a bad alternator. Get the car towed to your local mechanic shop for a complete charging system check.

How to Prevent a Dead Battery on a Cold Day

Aside from paying attention to the signs noted above, there are proactive steps you can take to protect yourself from a dead battery.

• Get your battery tested annually before winter. A battery test can catch a weak battery before it dies entirely. 
• Clean your battery terminals. Corroded battery terminals may prevent your battery from charging properly. 
• Drive for at least a 30-minute stretch once a week. Repeated short trips can drain your battery without giving your alternator a chance to recharge it.
• Park in a garage to protect your battery from the worst of the cold, if one is available.
• If you live in an area with extreme cold, consider investing in a battery warmer or blanket if you park outdoors. 
• Turn off your radio, lights, and other accessories before turning off your car.

What to Do If Your Battery Dies

If your battery fails despite your best efforts, you’ll need to jump-start your car. Regular jumper cables require a second vehicle, but a portable jump starter allows you to jump the car yourself. If you invest in a jump starter, be sure to charge it according to the manufacturer’s recommendations.

After jump-starting the car, drive around for at least 30 minutes to allow the alternator (which powers the vehicle while it’s running) to recharge the battery. It’s always in your best interest to have the battery checked if it dies to ensure the battery is still in working order. 

Roadside assistance is also an option. AAA Battery Roadside Service can jump-start your car without towing it to a shop. The technician will also test and replace your battery on the spot if needed.