EV BASICS 1O4: Does Winter weather reduce an EV’s range?

Does Winter weather reduce an electric car’s range?

Yes, it does!. Cold weather and winter driving conditions can significantly reduce the range in every car (including ICEs), yet it can be a bit higher with EVs. Like humans, EVs also perform the best only at the normal room temperatures😊.

But its not always as bad as 50% reduction as the media propagates. There're multiple factors involved and the media did not really fully understood the tests & report published by AAA (American Automobile Association).

Here’ a short technical explanation on why/how the range reduces and a few tips for the EV drivers to tackle the limitation.

Why EVs drain more quickly in Cold Weather?

In simple words: EV's battery cells rely on a series of chemical reactions to generate the required electric current. Lowering the temperature makes this chemical reactions to proceed more slowly. So if a battery is used at a low temperature, then less current is produced, thus less range.

You might have noticed that warming-up a dying mobile phone battery in your jeans pocket might provide a few minutes of additional run-time. It’s because of the same reason; warming-up the battery makes the electro-chemical reaction faster, which generates more current.

This doesn’t mean that the higher temperature always helps the battery either. EVs mostly use lithium-ion battery that are best performing only at around +15 to +35°C; operating beyond this range will not only reduce the capacity, but will impact the overall life of the battery too.

Plots Reference: https://www.nrel.gov/docs/fy13osti/58145.pdf

A few tips for the EV drivers:

Battery's electro-chemical reaction is a science fact that no one can change. However, there are a few things EV drivers can do to gain an extra couple of kilometers out of your EV in the winter.

1. PRE-HEAT YOUR BATTERY:

Always do the preconditioning, this heats up your cabin and batteries BEFORE you start the car - enabling the best range possible. Most of the recent EVs now feature applications that will take care of this for you, and this can increase the range considerably during the winter.

2. USE THE ECO-MODE SETTING 

Although it’ll make your EV a little slower, it avoids over-burdening the batteries, thus will fetch a few extra kilometers.

3. PLUG-IN WHEN YOU CAN

It’s a fact, Charging really helps to warm-up the battery. Keep charging wherever you can; regular charging will keep the batteries warmed-up and get you better range.

Note: EV charging takes more time with a cold battery. If 30-minute quick charge give you 80% battery full in Spring, it might only give you 50% in winter. Make sure to plan for the extra charging time.

4. AVOID ICE/SNOW DEPOSITS: 

Snow or ice on the car not only adds-up extra weight, but also keeps the battery temperature low. So always* brush away the ice/snow before you start the car. It's also useful to park your car in shed (to avoid snow deposit) or at sunlight (that will warm-up the battery).

* In extreme cold conditions (< - 20-25°C), sometimes leaving the ice on the car can help to retain the warmth too - due to the "Igloo Effect". The ice deposit keeps the temperature from dropping below zero degrees as well as protects you from wind chill.