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How Do I Keep My Car Battery Warm in the Winter

Power - by Bryan Veldboom - updated on 12/10/2021

Silver car at a stop sign

If you live in a cold climate, you know how hard winter can be on your vehicle's battery. Low temperatures force your battery to work harder to turn over your engine and if the charge drops too low, it won't start at all. Fortunately, you can avoid being stranded with some basic battery maintenance. Here are our top tips to help keep your battery warm this winter.

What Does Cold Do to a Car Battery?

Here are a few of the things that happen to an auto battery when the temperature drops.

  • Reduced Capacity: At 32°F, your battery's capacity drops by approximately 20 percent. At -22°F, it can drop by 50 percent.
  • Engine Oil Thickens: Cold temperatures cause engine oil to thicken, forcing your battery to work harder to start the engine.
  • Reduced Recharge Rate: Batteries recharge much slower in cold weather.
  • Battery Freezing: If your have an old battery in your vehicle, it can freeze solid at just -10°F.

What Happens When a Car Battery Freezes?

Vehicle batteries contain a sulfuric acid solution called electrolyte. When a car battery freezes, it causes this liquid to expand. This can warp the lead plates inside and cause the external casing to crack open. If your car battery shows signs of bulging or cracking or you notice icicles or frost on the terminals or plastic case you should not attempt to start your engine.

Can a Frozen Battery Be Recovered?

If you think your battery might be frozen, the first thing you should do is inspect the battery case. If you notice bulging or cracks in the case, the battery may be damaged beyond repair. Do not attempt to start your engine until you have the battery examined by an expert.

If the case appears undamaged, disconnect the battery and move it to a warmer location. Do not attempt to thaw the battery using any form of artificial means; allow it to thaw out on its own. Once the battery has thawed, reinstall it in your vehicle. If the dashboard lights or other electrical accessories won't work, you'll want to have it inspected by a battery expert.

If the battery is able to start your car, it's probably significantly discharged. Be sure to drive it for at least 30 minutes. If that's not possible, you should attach it to a battery charger to bring its charge back up again.

How Do You Keep a Car Battery Warm Overnight?

The best way to avoid the scenario above is by preventing your battery from freezing in the first place. If possible, park your vehicle inside during cold weather. You can also pick up a battery blanket. There are a number of commercial battery blankets on the market, featuring thermal insulation or corrosion-resistant fabric. In a pinch, you can even use a regular blanket.

Be sure to place the blanket on your battery as soon as you turn off your engine, as this will help retain the heat given off by your engine. Another important thing to remember is to be sure and remove the blanket before the next time you start your engine.

What are Some Other Ways to Keep a Car Battery Healthy in Winter?

There are a number of additional things you can do to help keep your battery from discharging.

  • Have Your Battery Checked - Test the battery yourself using a multimeter or bring it to any Batteries Plus location and have it tested for free. The test takes only a few minutes, but can help you avoid the hassle of being stranded with a dead battery.
  • Avoid Short Driving Trips - Short driving trips drain your battery without providing your alternator with enough time to charge it back up again. If you do a lot of local driving, try taking your vehicle out for a good 30-minute drive on the highway to help charge it back up again.
  • Use a Battery Charger - Do you have a vehicle you don't drive very often? Consider picking up a battery maintainer or other charger. A charger will help maintain your battery by keeping its charge from getting too low. Find out more about chargers in our blog entitled "When Should You Use a Battery Maintainer?"
  • Get an AGM Battery - AGM batteries are more resistant to cold weather damage than traditional lead acid batteries. They also recharge faster and discharge slower. Learn more about how AGM batteries perform in cold weather.

Batteries Plus is Your Vehicle Headquarters

Batteries Plus has everything you need to help you get through the winter. If you need to replace your battery, we have top-quality auto batteries from brands like Duracell Ultra and X2Power. Our Automotive Center features a number of seasonal essentials like jumper cables, portable jump packs, windshield wiper blades, spare headlight bulbs and more.

Are you looking for additional information? Our blog has plenty of answers. Find out how long you should let your car warm up before driving it or learn how to jump start a stalled car.

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