Winter Battery Care: Test It Before Winter Tests You

Cold cuts your battery's power in half. Test it in October, not after the first cold snap.

Why winter kills batteries

Cold slows the chemical reaction inside a battery, cutting its power by up to half at -20°C — right when your engine needs more power to turn over thick, cold oil. A battery that was fine in September can leave you stranded in January.

Signs yours is dying

• Slow, dragging crank on cold mornings
• Headlights dim when you start the car
• Clicking sound instead of a crank
• Battery is more than 4–5 years old
• Corrosion (white or blue crust) on the terminals

Test it free

Most auto parts stores test batteries for free in about five minutes. Get it tested in October, not after the first cold snap. A test beats a guess.

Watch: how to test a car battery with a multimeter

What a replacement costs

A new car battery typically runs $150–$300 installed, depending on size and brand. Cold-cranking amps (CCA) matter more than brand — match or beat your owner's manual rating.

Make it last

Clean the terminals, make sure the battery is clamped tight (vibration kills), and take the occasional longer drive — short trips in winter don't fully recharge it.

Related reading: What to do if your car won't start in the cold