How Efficient Is Your Electric Car?

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When you recharge an electric car, how far can it travel until the next recharge?

Now, the range of your electric car may not be an issue if you mainly travel short distances and can regularly top up the charge at home.

But what if you are travelling higher mileages, especially in a company car?

When you typically travel higher mileages, the efficiency of your car becomes more important.

So what do we mean by 'efficiency'? It's very simple. How far can you travel compared to the size of your car's battery?

Think of it like the miles per gallon (mpg) of a petrol or diesel car. The higher the mpg, the more efficient the car is.

Except that, with electric cars, the way efficiency is measured applies in reverse.

How Is Efficiency Measured?

The more miles you can travel in an electric car compared to the size of its battery, the more efficient the car.

Efficiency is measured by how far an electric car can travel compared to the size of the battery. The unit of measure is per 100 miles.

So, for example, if you have a car with a 50kWh battery and it can travel 200 miles on a full charge, the efficiency is 50kWh/200 miles = 0.25kWh per mile.

A car with a 100kWh battery that can still only travel 200 miles on a full charge would be less efficient at 100kWh/200 miles = 0.50kWh per mile.

This can be confusing, as the measure of efficiency is reversed.

With mpg you want more miles per gallon, but with electric cars you want less kilowatt hours used per mile.

Why Is Electric Car Efficiency Important?

Electric car efficiency is important because it effects both the cost of recharging and the time it takes to recharge.

If you typically travel relatively short distances and can recharge at home then efficiency perhaps doesn't matter as much as the cost of your car or its features.

But if you are travelling longer daily journeys and you have to recharge away from home, the battery efficiency of your car becomes much more important.

Why? Well, if you are charging away from home the cost typically doubles.

Home charging typically costs around 25p per kilowatt hour or less (depending on your electricity tarrif, especially if you have one of the electric car tarrifs where you recharge during 'off-peak' hours).

Public chargers are typically about double the cost of home charging, and faster chargers (which can get you back on the road quicker) are even more expensive, some times up to 3-4 times the cost of home charging (or more).

So how do you know the efficiency of your electric car?

Well, don't worry, we've built a calculator to do this for you.

About Our Electric Car Efficiency Calculator

Our electric car efficiency calculator will provides the published battery capacity of your new car and its range.

To work out the efficiency of your car we take the battery capcity (in kilowatt hours) and divide this by the range.

The resulting number is the efficiency of your electric car - how far it will travel on one recharge.

Keep in mind one important point though - the efficiency of your electric car will depend on how you drive it and whether you have enabled recharging when braking.

Keep in mind too that chargers may often only top-up your battery to around 80% of the battery capacity and therefore 80% of the range.

Why is this important?

Well, once you reach 80% capacity, sometimes the battery's lifetime is affected.

Recharging often to 100% capacity may shorten the life of your battery and this may, in turn, be visible to the car manufacturer if you make a claim on the battery's warranty.

Let's Get Started

Begin by selecting your electric company car. We'll then show you the efficiency of the battery compared to the range it can travel.

Remember that electric car efficiency can vary depending on the equipment you are using (such as the air conditioning or heater) and features such as heated windscreens and heated rear windows for de-frosting, plus how you drive it and whether you have enabled recharging when braking.

Please make sure you press the 'Enter' key on your keyboard/device when you type a value into a box.