How does hot weather affect EV range: Tips for reducing the risk

If you live in a part of the country where summers get hot — or you're planning a road trip to a warmer climate — you may not be able to count on the usual battery range of your electric vehicle (EV). On average, EVs lose 17% of their range when the temperature reaches 95 degrees Fahrenheit. That’s a smaller drop than you can expect in cold weather, but it’s still potentially disruptive. Plus, charging and storing your EV in extreme heat can shorten the battery’s life.

How does hot weather affect EV range? And how can you minimize the impact? Here's a quick science lesson, followed by some easy tips to help you get the most out of your EV battery when the heat is on.

How does heat affect an EV car battery

The problem isn’t warm weather. According to Consumer Reports, most EVs perform optimally on 80-degree Fahrenheit days. It's only when the temperature climbs into the high 80s and beyond that EV range loss and battery damage become an issue.

Of course, just like a gas-powered engine might degrade over time, EV batteries gradually lose capacity and the ability to hold a charge over time, too. But hot weather can speed up that process in a variety of ways. Be on the alert when:

• You drive in a lot of extreme heat. Batteries provide energy through chemical reactions, and if your EV battery gets hotter than usual, those reactions happen faster and become less efficient. Heat also increases the rolling resistance of tires and inspires us to blast the air conditioning. Both of those circumstances further stress the battery and drain its power.
• You park or store your EV in direct sunlight and/or heat. Hot sun shining down on your car heats it up, which can break down a protective layer around your battery and lead to faster battery degradation.
• You charge your EV on a very hot day. High temperatures make the electric current stronger, pushing lithium ions through the battery and potentially creating tiny cracks where secondary reactions can occur. This uses up the lithium and makes it more difficult for energy to flow freely.

Tips to help protect electric cars in hot weather

You can’t change the weather. But you can practice the habits below to help guard against reduced range and prolong the life of your EV’s battery when the mercury rises.

• Park in a garage, covered lot or shaded area.
• Pre-cool the vehicle while it's still plugged in, using an app or timer function if you have one.
• Use the vehicle's air conditioning system sparingly. Consider cooling yourself instead of the car — for example, dress for the heat and try lowering the windows for air flow. Some EVs even have seat coolers, which are much more efficient than cabin A/C.
• Keep the tires properly inflated to reduce rolling resistance and heighten efficiency.
• Keep your EV clean and clutter-free, ensuring that you don’t channel power toward hauling unnecessary weight. Cutting back by just a few pounds can have a positive effect!
• Avoid driving and/or charging during the hottest parts of the day, when possible.
• Charge your EV battery to 80% instead of 100%. A full charge creates more internal resistance and heat, further stressing the battery.
• If the vehicle has a “battery saver” and/or “hill-hold” mode, use them.
• Pay close attention to your EV range and plan for fewer battery-powered miles than usual when it’s very hot out. While every EV is different, all are affected by the heat to some extent.

In summary

Driving in higher temperatures impacts all vehicles. When it comes to EVs, that could mean decreased driving range on single charge, as well as reduced battery capacity over time. But you can minimize the impacts of extreme heat by practicing a few simple habits related to how you drive, how much you charge, where you park, and when you cool your vehicle on the hottest days.

To learn more about EVs, go to chase.com/EV.