Why is the distance an electric vehicle can travel on a single charge such a big deal?

AN electric car generally has a lot less range than a fossil fuelled car, and the replenishment process is rather different.

It’s rare to worry about running out of petrol as there is always a station nearby, and it will only take 5-10 minutes to fill up. Recharging your electric vehicle takes considerably longer, and finding a public fast charger on a road trip typically means pre-planning using an app.

Since range is an important metric, can you trust what the manufacturer says? If the car seller states a vehicle has a range of 400km, does this mean you will drive 400km every trip before charging?

The simple answer is no.

Range is never a fixed value and is affected by many factors, such as weather, driving habits, accessories, terrain, speed, tyre condition, passengers and luggage.

A standard is needed to compare EVs with each other, and in New Zealand, we rely on an international standard. The Worldwide Harmonized Light Vehicle Test Procedure – commonly called the WLTP – applies to all new vehicles, regardless of fuel/energy type.

The test cycle consists of a series of starts, accelerations, and stops over a set period of time. The cycle takes place in a controlled environment, where the temperature is maintained at 23 degrees.

The 30-minute cycle (WLTC) is split into four phases, named after their respective maximum speeds: Low, medium, high, and extra high.

When the NZ government established the Clean Car Programme, they created a database of emissions for all makes and models. They opted to use a single measurement, 3P-WLTP, meaning only results from the first three phases are used. They chose this because a high proportion of vehicle stock comes from Japan, which only uses the 3P-WLTP.

Europe, however, uses the full 4-phase WLTP. Some older vehicles may have never had a WLTP test and only have data from older test cycles (like the NEDC, for ‘New European Driving Cycle’). So all vehicle models have a conversion calculation applied to keep emissions data consistent.

WLTP range is slightly different. All fully electric vehicles have zero emissions, so whether 3P or 4P – the emissions calculations are irrelevant. When the manufacturer lists WLTP range – it reflects the complete 4-phase cycle.

For example, in NZ, the base Nissan Leaf is listed as 270km WLTP range. In Japan, the same Leaf is listed as 322km WLTP range. They are using only a 3-phase test cycle.

The WLTP predicts range better than its predecessor (the NEDC), but it still falls short of what you might achieve when driving your EV.

Even though the test cycle contains a phase at over 100kmh, it’s only for a short period of time (about 10 percent of the whole cycle). In city and suburban conditions, EVs thrive due to their ability to recharge the battery during every deceleration. In contrast, motorway driving offers little chance for battery regeneration and exposes the car to high aerodynamic drag.

Therefore the WLTP range is very optimistic and more accurately reflects the range you might get in summer, driving primarily urban and suburban roads at no greater than 80kmh. If your EV is used for open road or motorway trips, expect less range than the WLTP. My personal rule of thumb is to anticipate actual range to be about 77 percent of the WLTP range.

Every manufacturer wants to list the best range possible. It seems to me that occasionally they can ‘exaggerate’ claims. This happens when there are different trim levels in a model family. Each trim level will have its WLTP test, but in the advertising literature, only the most impressive range achieved might be listed.

The real-world range is an expectation of how far the EV can go in the ‘real world’. However, your real-world driving scenario might differ from mine; therefore, there is currently no scientific measure. Many enthusiasts routinely try to compare real-world range, and it can be helpful to look at some of these tests.

To add even more complexity, your EV will have a trip computer also doing its best to estimate the vehicle's range. New owners expect this ‘dashboard range’ to always match the manufacturer’s claims. However, the dashboard range is constantly changing. Each EV model uses algorithms based on past driving to assess range. If it’s been warm and you’ve been driving like your grandmother, expect the dashboard range to look very healthy. If you’re in winter and you’ve been driving with a heavy foot, expect the dashboard range to look very poor.

So how much range is enough? This depends on your use case, but as the charging network and vehicle charging speeds improve, range will become less of an issue.

Generally, more range requires a larger battery, which means more weight. More weight means more power needed to move the vehicle, therefore a bigger battery. It’s a vicious cycle, and given that bigger batteries require more metals and have a higher emissions profile during manufacturing, it’s worth considering what the ‘sweet spot’ might be in terms of range.

Most EVs are charged at home, overnight and never require a full charge for a daily commute. Given that the average daily driving distance for many Kiwis is just 22km, maybe we don’t need to wait for an EV that can travel 1000km between charges

James Foster’s EV data analysis can be found on EVDB.com