Tips for keeping your car battery charged in cold weather

Learn how to keep your car battery charged in cold weather

Winter can be a challenging time for car batteries. Cold temperatures can reduce a battery’s efficiency and increase the likelihood of it failing when you need it most. To ensure your car starts reliably, follow these tips to keep your battery charged in winter.

Drive your car on the highway at least once every two weeks to keep your car battery fully charged

Lead-acid car batteries lose about 1% of their charge PER DAY, even when the car isn’t being run. Plus, car computers draw little power even when the car isn’t running. So if you don’t drive your car for a month, you’ll wind up with a dead battery or at least a severely discharged battery.

If you start your car, turn on the headlights, blower motor, rear window defogger, and seat heaters, and drive round trip to the convenience store several times in a week, without longer drives, you’re taking more power out of the battery than you’re putting back in. That kind of use can leave you with a dead battery in just a week or so. So it’s really important to drive your car for at least 20 mins at highway speeds at least once every two weeks while running as few power items (heater, defogger, headlights, heated seats, etc.) as possible to keep your battery in peak condition.

You want to get the engine up to around 2,000 RPM so the alternator can output enough amps to fully recharge the battery. Starting it and letting it idle for 5 minutes with the blower, seat heaters, and rear window defogger on will actually drain the battery. It simply can’t recharge in 5 minutes at idle speed.

Keep the car battery terminals clean

Battery terminal corrosion creates electrical resistance, which lowers the voltage available for starting and prevents the battery from getting a full charge. The pictures I show here are worst-case examples of battery corrosion. If your terminals look like these, you should paste a big label on your forehead that says, “I don’t take care of my car.”

But battery corrosion doesn’t have to look this bad to create problems. I’ve seen voltage drops on battery terminals that look just fine. So next time your car is in the shop, have them clean the battery terminals and spray them with battery corrosion protectant.

Avoid running high-current items at idle

Yes, this is going to sound like the first paragraph, but it’s true. Your car’s alternator can’t produce full output at idle speed. When you’re sitting at the train tracks with your headlights, heater, heated seats, and defogger on, you’re draining your battery, and you’re overheating the alternator. Turn off a few accessories for maximum battery and alternator life if you’ll be idling for a while.

The takeaways

Cold-weather car battery care is pretty simple:

• Keep the terminals clean

• Drive it long enough to charge the battery, and

• Rreduce electrical loads when idling for an extended period.

• And be very careful when jump-starting. Use a jumper pack, and don’t volunteer to let other people use your car as the jumping vehicle—the jump can damage YOUR alternator.

For tips on how to test the condition of your battery, read this

For tips on how to buy a car battery, read this

For tips on buying a battery charger, read this

©, 2015 Rick Muscoplat