EVs in range: how far can an electric car go on a single charge?

Why is it so difficult to accurately predict how far an electric vehicle (EV) can travel before it needs charging? Weather conditions, traffic, payload and state of the battery can all have an effect. These variables make it difficult for drivers to figure out how often to charge their vehicles, and how much charge is left.

This matters as concerns about charging can still be a significant barrier to uptake, especially among people who have never owned an EV before.

Calculating range is much more complex than it is for internal combustion engine (ICE) vehicles. It can be so tricky to calculate that HERE has discovered that many automakers get it wrong. Typical remaining range forecasts are overestimated by about 20%. This means that if your vehicle says you have 160km left to go, it is more likely to be about 120km.

The inaccuracy is mostly because these calculations were originally based on internal sensor information, excluding important factors such as external temperature and road elevation that can eat into power.

Experts at HERE have performed their own tests and found that for an EV with a typical 88 kWh battery, the estimated range for a typical urban commute is 550km. That is in a vehicle with one occupant, traveling at about 36km per hour, without the heating or air conditioning on.

On a long-distance trip with three occupants and their luggage and the heating on, going at higher speeds, the range for the same vehicle is reduced to 380km: a 31% difference.

Righting the range

HERE uses map conflation to pull together data on some of the factors that can impact range, helping drivers understand how far they can travel. These include traffic conditions, as well as data from inside the car. This includes information about battery size and type of car.

When all this information is put together it can help us to build a more accurate picture of the charge left in the vehicle.

The right routing tools are important to help the driver plan when and where to charge. This is especially important with EVs, as they take longer to charge than ICE vehicles. Depending on the vehicle and charge point, the charging time can vary from about 45 minutes to four hours or more.

A recent trend for bigger batteries has only increased the time spent charging. The driver must factor this waiting time into any journey. To help with that process, machine learning can help to predict how likely a charger is to be available and in working order when they get there, dynamically adjusting as you make your journey.

“EV drivers are navigating a patchwork of infrastructure, with various plug types, pricing, and little understanding of when a charge point is occupied," said Chris Handley, HERE VP Dynamic & Spatial Content Business Unit.

In the US last year, one in five attempts to charge an EV failed — thanks to payment systems or technical faults with the charge point, amongst other reasons. This makes it all the more crucial for drivers to know whether a charger is functioning before planning their route.

Technology that supports EVs will only continue to improve as further factors that predict range get added to the picture. Historic data will be used to help forecast what the weather or traffic is likely to do, based on what typically happens at that time and location. Personalized information, including driver behavior and typical loads in the vehicle, will gradually be added to create an even more precise picture.

While none of this will put more charging infrastructure onto the roads, it will give peace of mind to EV drivers and help them plan their trips.