How summer heat zaps your car battery

July 29th, 2019  |  Auto

Feeling sluggish in the extreme heat? Chances are your car battery is too.

And with temperatures soaring this summer, that’s why the CAA South Central Ontario has issued a warning to drivers to check their batteries. The insurer did so after reporting an eight per cent increase in car battery-related calls during the summer months.

Although people worry about losing battery charge during the winter, extreme heat can cause your battery to lose its charge 33 per cent faster than in the winter months, the CAA said. Increases in outdoor temperatures also lead to increases under the hood, so an average 32°C day could mean your vehicle’s inner temperature could be closer to 60°C. Some studies suggest that car batteries are even more likely to fail in the heat of the summer than they are in winter.

Interstate Batteries, a company with 190 locations in the U.S., Canada, and Latin America, explains it this way: high temperatures can evaporate your battery’s vital liquids.

Pre-aging of battery

“If a battery gets hot enough, its internal components corrode and weaken how much power the battery has,” the company said. “Think of it as pre-aging a battery.”

Hot temperatures can speed up the corrosion process and irreversibly damage the battery’s internal structure. The problem is compounded if your battery is “parched.” While most car batteries are sealed and don’t require maintenance, some need to be refilled with water. If your battery is that type, make sure it’s topped off.

When winter comes, “Temps don’t have to fall far to make starting a car too hard for a heat-weakened battery. Cold kills car batteries and heat is its accomplice,” said Interstate.

Ways to beat the heat

Interstate offers these tips to keep your battery in heat-fighting shape:

  • Limit short car trips. Your battery doesn’t have time to fully recharge on short stop-and-go trips, which can cause it to weaken sooner.
  • Double check you turned off interior and exterior lights when you leave the car.
  • Keep your battery and battery posts clean. Dirt becomes a conductor, which drains battery power.
  • Don’t use electronics (like the radio) when the engine is off.
  • Park in the shade or garage to protect your car from direct sunlight.

There are some signs your battery is failing. Some are simple and others may require a battery test.

  • The engine cranks slower than normal when you start your car.
  • The check engine light or battery light is on.
  • You see the fluid level is low on the battery.
  • The battery case looks swollen.
  • The battery posts (where the cables connect) are corroded.
  • Your headlights or interior lights are dim.
  • Your battery is more than three years old.

Related stories: Seasonal battery care

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