EV batteries in cold weather

People across the country have witnessed a sudden, sharp drop in temperature over the past week, causing many to allocate extra time in the morning for defrosting their cars, and preparing for a potentially longer journey due to icy conditions. Most drivers are clued up on how to drive safely when the temperature drops below freezing, but fewer drivers are aware of the implications that colder weather can have on their EV batteries.

If you need help understanding any of the terminology in this post, check out our EV glossary.


What effect does cold weather have on an EV battery?

When a lithium-ion battery (used in most EVs) is plugged in to charge, the charger pulls lithium ions from the cathode, adding an electron to convert them to lithium atoms, and then embeds them into the graphite on the cathode. If the temperature drops below 15℃, the atoms cannot embed into the graphite, instead, they coat the surface of the anode, causing lithium plating. Due to this, the number of lithium atoms that are available for providing electrons is reduced, which results in decreased performance of the battery.


We’ve compiled a list of handy tips to help you care for your EV’s battery throughout the colder months, as well as methods to increase the battery range.


Slow and steady wins the race

Fast charging an EV in cold weather increases lithium plating, which as we mentioned above, is the reason for reduced performance. The safest way to charge an EV in colder temperatures is to charge it on a low level for an extended period of time, as this keeps the battery warmer for longer. This may require some extra time planning, but it is important for maintaining your battery’s health, so it’s worth the slight change in schedule.


Keep the battery topped up

It isn’t recommended to leave an EV overnight in low temperatures with less than 70% battery, as sitting at a low charge can damage the battery. It’s advised to leave your vehicle charging overnight, but if this isn’t possible, try to sufficiently charge your battery in the evening so that it can sit at a healthy percentage throughout the night.


Keep your EV warm

If possible, park your EV in a heated area, such as a garage. EVs can lose charge when they’re not in use, and this is only amplified in cold weather. If you do not have a heated area to park your vehicle, consider investing in a car cover to help take the edge off of the frost when parked outside. Keeping your EV warm when it isn’t in use also reduces the risk of low temperatures damaging the battery.

Preheat your EV

Before heading out on a journey, allow your EV to slowly warm up whilst stationary – most EVs have preconditioning, which allows you to cool or heat your vehicle prior to driving. Some EVs allow you to set a time for preconditioning to begin, meaning it will automatically begin warming in time for you to set off for work. If you don’t preheat the vehicle, a large amount of strain is placed on the battery as you begin driving, due to the EV heating rapidly. If you leave the vehicle plugged into the charger whilst heating, the power will be drawn from the charger, not the battery, so there’s no implication on the range.


Drive in Eco mode

Driving your EV in Eco mode decreases the load on the battery and provides a better range, whilst also being kinder to the environment – sounds like a win-win-win to us!


Use alternative methods of heating

Not only does an EV battery fuel the vehicle but it’s also used to run the heating systems. To increase the range of each charge, try to use alternative heating methods wherever possible, such as heated seats or steering wheel, as these use less power than the main heating system.


Use lower regenerative braking

Most EVs have various settings for regenerative braking, which allow the vehicle to charge whenever the brakes are applied. The higher the setting, the higher the currents sent to the battery are, which risks causing damage to the battery in colder temperatures. Alongside this, a higher setting of regenerative braking can cause the vehicle to slip on snow and ice, so keep the setting low to prevent risks to both your battery and your safety.


Check tyre pressure regularly

All vehicles with inflated tyres are affected by lower temperatures, so petrol and diesel cars can also be affected. Every 10℃ drop in ambient temperature can decrease tyre pressure by 1 PSI. This is especially important for EVs, as maintaining the optimum tyre pressure increases the vehicle’s energy efficiency, prolonging the range.


Implementing these tips will help prolong your vehicle’s range throughout the winter months, and prevent long-term damage to the battery. If you need any further advice on caring for your EV in winter, contact our expert team.


Photo by Oleksandr Pidvalnyi: https://www.pexels.com/photo/red-sedan-in-the-middle-of-forest-376361/