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Heat and your electric car battery

Summer heat can cause your electric car batteries to heat up. Here you have information and some advice so that you can charge without problems.

María Rodríguez
Jun 30, 2022
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With summer in full swing and temperatures soaring, new EV users are beginning to wonder how the heat will affect their performance. While long motorway journeys in the summer heat can get your batteries really hot, remember that you are not driving a combustion engine, which obviously generates a lot of heat. We’ve put together some information and a few tips for your travels so you can charge without any problems this summer.

How does heat affect the batteries in electric vehicles?

Batteries and Overheating

Lithium-ion batteries are unable to withstand extreme temperatures. In fact, they work best at temperatures within the range of 20-25°C.

The risk of battery overheating increases in summer, which is also when people tend to drive at higher speeds and make longer journeys. Above 45-50°C, the electronic components of the battery deteriorate more rapidly and there is a drop in charging performance. Many electric vehicles have battery cooling systems, and therefore the heat may affect them differently. Remember, however, that there is no combustion engine to add to that heat.

Battery Cooling System

Your electric vehicle's on-board cooling system plays a role in keeping your battery in peak or low heat conditions.  Today, many electric car models have high-performance cooling systems that use liquid coolant. This is the case for some Tesla, Kia or Hyundai, just to name a few.

Other vehicles, instead, use forced-air cooling to regulate battery temperature, which is less efficient. Therefore, remember to check to see which system your electric vehicle has and adjust trips in hot weather to take this system into account.

More Autonomy

Moderate summer temperatures lead to a longer runtime for the EV battery, because it consumes less energy. Warm weather is therefore good for an electric car battery.

Our Customer Support Manager, Emilio J. Fernández, one of the pioneers in electric vehicles in Spain, shares his experience:

“A few weekends ago I drove 1,300 km with my Tesla Model S, from Madrid to Marbella, and the consumption was about 2 kWh/100 km less than on the same journey last December. More specifically, I have 10-15% more battery autonomy in hot weather. On top of that, if the EV battery has a good battery management system (BMS) and liquid cooling per battery, the car should charge perfectly. In fact, batteries work best at 20°C, so summer weather is much better than 0°C in winter".

However, some electric cars have relatively poor cooling, sometimes referred to as "passive" cooling, so the BMS reduces power during charging sessions to protect the battery and reduce degradation. As a result, charging sessions take longer than expected. This scenario is referred to as "rapidgate".

Does heat affect charging stations?

Yes, heat also affects the electronic components of charging stations. Public charging infrastructures generally work optimally up to temperatures of 50°C and offer very high-performance levels.

The root of the problem lies in the fact that public charging stations are rarely protected. Today, most charging points located outdoors are not equipped with a roof or protection against extreme temperatures. There are, of course, some exceptions, such as charging stations fitted with a solar panel covering to generate additional power. Fortunately, roofed charging stations are becoming more common, even though many stand in full sun.

Oddly enough, fuel pumps at petrol stations are usually under a roof while electric vehicle charging stations are not.

The bottom line is that, like the battery of an electric vehicle, charging stations can limit the power delivered when temperatures are high.

What about the energy consumed by air conditioning?

Like most internal combustion engine vehicles, the use of air conditioning, especially in extreme temperatures, has a negative impact on range.

Just like the cooling system, it depends on how the air conditioning is generated. The impact is lower for electric vehicles equipped with a heat pump with reversible air conditioning. This system is becoming more widespread because it consumes less energy.

It is the ideal solution for driving in pleasant conditions, both in summer and winter, without the stress of draining the battery.

When your electric vehicle is equipped with a heat pump, the energy consumed by the air conditioning system will be quite reasonable.

Our tips for stress-free charging in the sweltering heat

1. Choose the right charging stations in summer

Aim for sheltered charging stations or charging points located in underground car parks, preferably shaded charging stations. Ideally also for travel; look for charging points that also offer services such as cafes, bars or restaurants, so you can hydrate yourself as well. The photos posted by the Electromaps community on the mobile app will help you choose the best charging points.

Important: If you plan to install a charging point at home, consider its orientation and make sure it is well protected, especially if it is outdoors.

2. Best time to charge: at night or early morning

You should plan for your charging and also your journey times. We recommend charging in the evening or early in the morning, to make charging more pleasant for both you, as it can be timed to fit in with your rest hours, and for your electric vehicle. It's a win-win situation for everyone.

3. Turn on the air conditioning before you head out

For the best possible start to your journey, some vehicles have the option of 'pre-cooling' the passenger compartment when charging. This enables the air conditioning to draw its power from the mains rather than the battery.

You therefore start with an ideal ambient temperature and maintaining it at this level will require much less energy. A great solution to optimise your battery performance during a long journey!

The pre-cooling settings on most electric vehicles can be programmed, either via the dashboard or remotely from the manufacturer's app.

4. Don’t rush

Adopting a smooth driving style rather than aggressive steering is beneficial in all circumstances, but even more so in times of extreme temperatures. Speeding will always be detrimental to your battery life. Remember, too, that every summer there are millions of journeys and, unfortunately, many accidents.

If you are a veteran electric vehicle driver, do you have any other tips for driving and charging your electric car with peace of mind during the summer season?

For new electric drivers, did you find this information useful?

Best of luck in the sun!

María Rodríguez
Jun 30, 2022
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