Winter charging tips for EV drivers

With the colder weather approaching we explain how the cold can affect your Electrical Vehicle, and the steps you can take to keep your car and your car battery in prime condition for high performance winter driving.

1. How the cold affects battery power

Most EVs have two batteries under the bonnet - the main high voltage lithium-ion battery that’s used to start the car and drive the motor, and a back-up 12V battery (like you’d have in a petrol or diesel car) to run the vehicle’s ancillary systems like heaters, air conditioning, electric windows, heated seats, headlights and onboard computers. When your car is plugged in, electricity charges the main battery and this in turn charges the 12V battery. 

Both batteries will be similarly affected by the cold, as freezing temperatures slow down the chemical reactions within the battery, thereby reducing battery performance. For EVs, this can result in reduced driving range. 

2. Preheat your car 

With an EV, if your car is plugged in to charge, you have the luxury of being able to turn on the car’s heater before you set off on your journey, without draining the batteries. Not only will this get your car heated to the desired temperature, your car batteries will also be warmed up to promote better performance. When it’s really cold, why not put on the heated seats in advance too, for a cosier ride? In fact, these days, most EVs come with apps that allow you to do this remotely from the comfort of your home, so no more icy fingers!

3. If you have a garage, use it

Not everyone has a garage at their disposal, but if you do have one, turf out all that junk and use it! When cars are indoors in cold weather, battery performance is improved because the heat from the garage ensures your car charges faster and retains the charge of the battery for longer. Keeping your vehicle stored in either a temperate area or climate-controlled garage are the best options for extending battery life. If you’re on the road and have the choice between parking outside or in a parking garage, then definitely choose the latter.

4. Don't let the battery get too low or too full

The car's main battery reserves around 15-20% of battery capacity in the freezing cold to warm up the battery. If you keep the battery above 15-20% charged, and ideally at least 50%, then there’s a nice margin to keep your car’s performance at an optimum level. 

CTEK also recommends that you don’t fully charge your battery every day, as this can be bad for your battery and cause it to drain faster. For daily use, CTEK recommends a charge of 90%, but if you’re going on a longer trip, then of course it’s fine to charge the battery to 100%.  

5. Using eco mode

The eco mode for each EV differs, but they all have the same goal - to cover more miles by using less energy. For example, by limiting the energy supply to the drive motor and the heating elements inside the car, considerable savings can be made on energy. This helps to maximise battery efficiency in colder weather.

It’s also reassuring to know that most EVs accelerate a little slower in eco mode, because less energy goes to the engine. This makes driving safer by reducing the risk of the car wheels spinning on roads covered with ice or snow.

6. Reduce regenerative braking

Some cars use ‘regenerative braking, where the wasted energy from the process of slowing down a car, when the accelerator is released or the brakes applied, is used to recharge the car's main battery. If your car allows you to set the amount of regeneration, if it’s icy outside it can be a good idea to lower it a bit. Effective regenerative braking and icy roads can cause some cars to behave differently to usual and become sluggish by releasing the accelerator too quickly.

7. Extra energy in the battery

In cold weather, always make sure you have some extra charge in the battery, more than your trip really needs - either 90% for general driving, or 100% for a longer trip. If you get stuck out in the cold due to an accident, a road closure or any other event that can hold you up, it’s a good idea to have plenty of charge. You can then, for example, keep your car warmer for longer or use it to charge your phone if required.