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Summer’s Sizzle Can Take a Toll on Your Car’s Battery

Aug. 3, 2021
4 mins
A young woman drives with the sun reflecting behind her

It seems contradictory, but summer heat can be tougher on your vehicle and its battery than the cold grip of winter. That’s because high temperatures can zap your car’s battery by weakening its charge, and lead to structural damage and corrosion.

According to CAA South Central Ontario, a vehicle’s battery can lose its charge 33% faster in extreme heat compared to the frigid winter. Moreover, when the temperature outside reaches 32 C on a hot summer day, the temperature inside your car can hit 60 C or higher.

Car batteries are designed to last from three to five years. Getting your battery inspected by a certified technician as part of your vehicle’s routine maintenance is essential, especially if you’re planning a family road or day trip before summer winds down.

Why car batteries can deteriorate and die in the summer

Summertime heat can trigger four problems that can deplete a gas-powered car’s lead-acid battery charge and lead to its failure, including:

  1. Evaporation. Vehicle batteries need electrolytes (water and sulfuric acid) to fuel the internal chemical process they need to operate properly. In extreme temperatures, electrolytes evaporate, and inevitably, the battery will begin to die.
  2. Sulfation. Sulfation is when lead sulfate crystals build up on the surface of a battery and remain on the battery plates. It’s the no. 1 cause of early battery failure in lead-acid batteries. This chemical process happens when a battery is deprived of a full charge and impedes the chemical to electrical conversion it requires to work. That, in turn, will dramatically shorten battery life.
  3. Corrosion. High temperatures and evaporating electrolytes trigger oxidation. That leads to the battery corroding faster than it should.
  4. Overcharging. High heat causes your battery charging system to malfunction, overcharging it. Like any electronic device such as your mobile phone, if overcharging occurs in your vehicle’s battery, it will reduce its lifespan.

Will summer’s heat affect electric vehicles?

Many electric vehicles (EVs) use lithium-ion batteries. They too are susceptible to high temperatures. It’s recommended to park your EV in a shaded area whenever possible, and if you use a public rapid-charging station, try to find one that’s in a shelter or opt for a slower charge. When you are powering it up in hot weather, refrain from charging it to the max on a regular basis or the battery may get too hot. That can accelerate the battery’s cell degradation, which is when lithium-ion batteries lose the capacity to recharge.

Keep cool and motor on

CAA offers the following tips to drivers to maximize their car’s readiness for the summer months ahead:

  • Have your car and its battery regularly maintained.
  • Keep your car cool by parking in a garage, carport, or under a canopy. If these are unavailable, even a large tree can give the shade needed to keep cool. Window coverings will help keep the cabin of your car cool too.
  • Clean the top of your car battery and the connections to prevent discharge.
  • Flush your cooling system with fresh coolant periodically. Coolant can become acidic over time which can eat away at hoses and seals and lead to an overheated engine.
  • Keep an eye on your vehicle’s air conditioning. If it is not maintaining the interior temperature well, it may mean the refrigerant level is low. Have your air conditioning system inspected by a certified technician.
  • Ensure your tire pressure is spot on to the manufacturer’s recommendations. Driving with improperly inflated tires affects the handling and braking of a vehicle. It can also cause tires to overheat and increases the chance of a blowout.

Does your vehicle have the right battery?

If you’re thinking of buying a new battery for your vehicle, start by checking your owner’s manual to ensure you purchase the right kind of battery for your car or truck. Most gas-powered vehicles use either a traditional lead-acid battery or an absorbed glass mat (AGM) battery.

And take note: you can recycle an old lead-acid car battery. Bring your discarded battery to the repair shop or retailer you purchase a new one from to dispose of it but be mindful of the safety precautions outlined in your vehicle owner’s manual if you are going to remove and transport a dead battery.

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Liam Lahey

Liam Lahey is a versatile, seasoned writer and editor. He worked as both a staff writer and freelance writer for many business and technology publications as well as for several newspapers. He writes about home, auto, and travel insurance, and is a media spokesperson for RATESDOTCA.


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