How Summer Heat Affects EV Battery Range and Charging

With summer rapidly on the way, a scorching day can be tough on vehicles. Whether electric or gas-powered, both have to work harder to stay cool and can lose fuel efficiency as the mercury climbs. Extreme heat can even chip away at the longevity of some vehicle parts. But with smart charging and driving habits, you can keep your EV running efficiently and ensure its long-term health.

While EV batteries are designed to withstand extreme weather, they fare best in moderate conditions. When the heat rolls in, you may notice changes in a vehicle’s performance, and high temperatures can take a toll on batteries over time.

Like vehicles with internal combustion engines, EVs rely on cooling systems to weather the heat. An EV’s thermal management system regulates battery temperature, typically keeping it around 20°C to 30°C (68°F to 86°).

Maintaining that comfortable temperature does comes at a cost: both the thermal management system and the air conditioner that cools the vehicle’s interior draw power from the battery. In theory, this increased energy demand means an EV may not go as far before it needs to be recharged.

In practice, the impact is often minimal in moderate to high temperatures. A Recurrent study found that EV batteries lose only about 5% of their usual range at 32°C (90°F). Once temperatures hits 38°C (100°F), however, range drops by 17%-18%.

Over the long term, consistent exposure to high heat can speed up battery degradation. Fortunately, EV owners can take practical steps owners to help maximize battery lifespan, even in persistently hot climates.

Most EV manufacturers recommend keeping battery level between 30% and 80% year-round. This becomes even more important when temperatures soar because batteries tend to heat up as they approach their full storage capacity.

DC fast charging works by converting an alternating current (AC) to a direct current (DC) before delivering it to an EV battery. This method can replenish an EV battery swiftly, but it also boosts the battery’s temperature.

On the hottest days, opt for Level 2 charging stations and save fast charging for when there’s a break from the heat.

Regardless of charging speed, try to plug in when temperatures are lower, such as overnight, early in the morning, or on overcast days.

Preconditioning brings a vehicle to its optimal temperature before you start driving, which can lower the demands on a battery in both hot and cold weather. Using the vehicle’s app or its onboard system, set the cabin temperature before you hit the road—ideally, when the vehicle is plugged in, so it’s powered by the grid, rather than the battery.

This is an easy one: whenever possible, park in shaded areas or indoor facilities to reduce heat exposure. Shade lowers interior temperatures, so your cooling systems don’t have to work as hard.

A Geotab study found that speed has a more meaningful impact on driving range than heat, especially on highways. Reducing speed by as little as 10% can extend driving range by as much as +30%. So, when the pavement is hot enough to sizzle your toes, keep your lead foot in check to help preserve battery life.