Electric vehicle in hot weather – the impact on charging

How heat effects EV batteries

Battery overheating

As mentioned when we looked into the impact of cold weather on EV range, lithium-ion batteries don’t take kindly to extreme temperatures. In fact, they work best at temperatures of between 20 and 25°C.

The risk of overheating the battery is increased during the summer when you drive at higher speeds on long journeys. Beyond 45-50°C, the battery’s electronic components deteriorate more rapidly and a drop in charging performance is observed. Of course, the temperature range varies according to the EV model and the phenomenon will be more or less acute depending on the quality of your battery. 

If you want to look into this further, you can read our tips on maintaining satisfactory battery performance over time.

Impact on charging rate

As the battery approaches the point of overheating, the charging speed decreases. What happens is that the battery management system (BMS) adapts the charging rate to the temperature of the battery. To prevent overheating, the charging rate and charging time will be impacted to a greater or lesser degree.

In extreme cases, charging may even be halted for safety reasons while the battery cools down.

Battery cooling system

Having said that, depending on the cooling system on board your EV, your battery won’t be affected by heat to the same degree. Most recent electric vehicles now incorporate sophisticated thermal management systems, generally based on a liquid cooling circuit. This technology, which is used by many manufacturers, maintains battery performance even in very hot conditions.

Some vehicles, however, regulate the temperature of the battery via forced air cooling, which is less efficient. So think about checking what system your electric vehicle is equipped with and adapt your journeys in hot weather to take this into account.

And what about combustion engines vehicles?

We often talk about the effects of heat on electric vehicles, but we forget that it also has an impact on combustion engines cars.

During heatwaves, combustion engines can overheat, particularly on long journeys or in traffic jams. This can lead to a loss of performance and even breakdowns in the cooling system.

Another point that is often overlooked is air pollution. Internal combustion engines emit more fine particles and polluting gases in hot weather, which worsens air quality, especially in town. Conversely, an electric vehicle produces no local emissions, which is a considerable advantage during heatwaves and pollution alerts.

Are charging stations affected by heat?

Yes, heat also has an impact on the electronic components in charging stations. Public charging infrastructures usually operate best up to temperatures of 50°C. And here again, we’re talking about charging stations offering the highest performance levels.

In the most extreme cases, with temperatures exceeding 45°C, some terminals may trigger a safety measure to prevent overheating. Recharging may be either reduced or temporarily interrupted.

The heart of the problem lies with the fact that public charging stations are rarely sheltered. While many outdoor charging stations do not yet have specific shelters, operators are stepping up initiatives to improve their resilience in hot weather. Some exceptions can be noted, such as charging stations on the Fastned network, which are fitted with a solar panel roof. These are becoming more widespread in France. 

This means that, just like your electric vehicle, charging stations may limit the power rating delivered in hot weather.

What about the energy consumed by air conditioning?

The use of air conditioning in very hot weather can lead to a slight reduction in range. However, recent advances in heat pumps and intelligent air conditioning systems mean that this impact can be limited, particularly on the latest models.

As with the cooling system, it depends on how the air con is generated. The impact is lower for electric vehicles equipped with a heat pump with reversible air conditioning. This system is, moreover, becoming more widespread as it consumes less energy. It is the gateway to driving in pleasant conditions in both summer and winter without the stress of draining your battery. 

If your EV is equipped with a heat pump, the energy consumed by the air con system will be totally reasonable.

Our tips to avoid the stress of charging in sweltering conditions

First and foremost, let us not forget the initial key phase of ensuring a successful e-journey – planning. To set off in the best possible conditions, don’t forget to plan your route using the Chargemap route planner.

Opt for sheltered charging stations or charge points located in underground car parks

As we mentioned earlier, charging stations are also sensitive to heat. It is therefore a good idea to go for charging stations fitted with a roof or located in underground car parks. The photos published by the Chargemap community on the mobile app will help you choose the best charge points.

A charging stop in a shaded environment will also be beneficial for your EV as it will be able to cool down more efficiently. Even without charging, parking in the shade or in a sheltered spot whenever you can will slow down wear and tear on your electric car.

If you are thinking about installing a home charging station, bear this in mind when you choose the location (either in your garage or a well-protected spot if it is outside).

Charge up early in the morning or at night

Along the same lines, it is a good idea to plan your journey so that you charge early in the morning or at night whenever possible. During heatwaves, this will help you benefit from more bearable temperatures for yourself, your EV and the charging station. A win-win combo!

Avoid systematic 100% charging

In both summer and winter, it’s generally advisable to avoid systematically charging your battery to 100%, unless you need maximum range (for example, for a long journey). Keeping the charge between 20% and 80% helps to limit thermal stress on the battery and preserve its longevity.

That said, this is not an absolute rule. Other factors have a much greater impact on battery wear and tear: the type of charging point used on a daily basis (fast or slow charging), your driving habits, the way the vehicle is stored and even the weather conditions.

👉🏻 Also read: Should you charge your electric car every day?

Activate the air con inside your EV before setting off

To start your journey in the best conditions, you can pre-cool the cabin of your EV while it is plugged in. In this way, the air con draws energy from the grid rather than from the battery. You therefore start off with an ideal ambient temperature and keeping it at this level will require much less energy. An ideal solution to optimise the performance of your battery on a long journey. 

On most electric cars, you can programme the preconditioning settings for the temperature and the time the pre-cooling is activated, either via the dashboard or remotely using a carmaker app.

Ease off the accelerator

If you are a regular reader of our articles, you will know that this advice crops up very often. But a quick reminder never does any harm! Smooth driving rather than abrupt movements or racy driving is beneficial in all circumstances, but even more so during periods of extreme temperatures. Discover the tiny reflexes you can adopt to economise the battery of your electric vehicle. Every little helps and adding up an array of small habits can make all the difference in the long run ?

We hope you have found this article informative and that you will now be able to travel by electric vehicle stress free – even in the hot summer weather. Please don’t hesitate to share feedback and your own tips on this topic in the comments. All that’s left for us to do now is to wish you a safe journey and happy charging as summer rolls in ☀️

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