by Rolf Limacher (2022)

Many car owners are reluctant to replace their combustion-engined car with an all-electric car. They might refrain from buying one not only due its considerable price tag but possibly also due to the reduced range and the duration of charging stops.

After we had cleared the first hurdle of car purchasing, we undertook our first long-distance trip in July 2022 in the EQV 300 from Mercedes as a family with three almost grown-up children and a dog. It turned out to be a really pleasant experience.

Our 3000km round trip starting from the Netherlands and including the Swiss Alps, required however some planning as we had the new car delivered to us only three months earlier and therefore had neither developed a feeling for its range (especially in the alpine environment) nor for its repeated charging at rapid charging stations.

Although there are many different providers of rapid-charging networks for electric cars in Europe, which span combined an dense network, especially in the Netherlands and Germany, both their reliability and the tariffs proved to be unsatisfactory during personal test runs in the Netherlands and Great Britain. Some charging stations turned out to be very busy, not functional and/or to refuse our payment attempts, which led to prolonged queue times or required a detour to another charging location. In addition, the various providers of rapid chargers exhibit an astonishing tariff range with the costliest one being up to four times more expensive than the cheapest.

For this reason, we decided to only haunt on our trip charging stations of the very single provider from which we had a subscription. This would allow us to charge the car battery sufficiently in a relatively short time for a uniformly low price. The individual charging stations of our provider consist usually of four rapid chargers, which allow thus up to four vehicles being charged concurrently.

The batteries used in today’s electric vehicles allow fast charging at rapid charging stations, but for technological reasons the charging is slowed down automatically as soon as the battery charge level exceeds about 75%. This means that the battery of our electric car could be charged from 10% to 80% within 45 minutes, but that it would take significantly more than an hour to get the battery fully charged.

In order to maximize the battery life time, the car manufacturer recommends to initiate charging only when the battery charge drops below 30%. Taking into account a safety margin, charging should therefore preferably be initiated within a charging window of 5% – 30% of remaining battery charge. This represents a significant limitation compared to cars with combustion engines when it comes to scheduling the refueling. The manufacturer of our car therefore provides the “Electric Intelligence” travel planning tool as part of the vehicle’s navigation system, which would not only recommend appropriate fast charging stations along the route after a travel destination had been entered into the navigation system, but would also indicate the percentage to which the battery would have to be charged at each of the automatically determined charging stations to enable the charging window to be reached again at a subsequent charging station.

According to our test runs, the “Electric Intelligence” system appears to currently not support the dynamic adjustment of route and suggested charging stops, resulting in intolerable navigation suggestions in case of the driver ignoring a suggested stop. The system also does not offer a filter option to only consider charging stations from preferred providers.

Because of these teething problems, we decided not to use the “Electric Intelligence” for this first long-distance trip. We manually identified all preferred charging stations on the route in advance instead, from which we concluded that their location density would be sufficient for our trip. We then determined which of these rapid-charging stations we would visit and to about what percentage we would charge the battery in each case, which also included ensuring that the charging would take place at lunch or dinner time. This determination was done based on a self-developped model implemented as a spreadsheet, which also took the effect of steep ascent and decent on the consumption in a simplified manner into account, namely as an additional 10% consumption decrease/increase per 100m altitude difference for trajectories.

The official reference range of 336km indicated for our electric car according to the WLTP (“Worldwide harmonized Light vehicles Test Procedure”), which corresponds to an average consumption of 27kWh per 100km, turned out to be way too pessimistic given our car driving pattern. We were actually able to maintain a consumption close to and even below 20kWh/100km while traveling with an average speed of about 90km/h on the motorways from the Netherlands via Germany to the Swiss Plateau. On the way back to the Netherlands, we even managed to drive once over 400km without charging the battery.

This resulted in an extremely pleasant travel rhythm for the journey with sections of three to four hours driving time, interrupted by rest breaks that were anyway necessary for the driver to recover. Fortunately, we found in most cases at least one immediately available charger at each of our fast-charging stops.

As expected, car driving in the Alps resulted in an increased consumption for a steep ascent (as e.g. 65kWh/100km on a 20km section overcoming 1000 meters of altitude difference), whereas during the equally steep descent almost three quarters of the energy used for the ascent could be recovered through recuperation, i.e., re-charging the battery while driving.

Analyzing the data collected during the trip, it turned out that using for the model a flatland range of 425km, which corresponds to a consumption of 21kWh / 100km and targeting a charge level of 25% at each of the rapid charging stations, would reflect the reality such that the set charging window requirement, namely to be between 5% and 30% when reaching a charging station, could be ensured for any reasonably imaginable situation. Unfortunately it turned out, that the trajectory-based power consumption as displayed in the dashboard of the car, had to be considered to be a mere indication rather than representing a reliable value, since it eluded any attempt to match it to distance travelled combined with battery charging level difference, and with reasonably expected current maximum battery capacity.

In summary, we can conclude that long-distance journeys in an electric car are very relaxed if you know your car and given a proper route planning. The increased driving time caused by the lengthy charging stops of an electric car appear to be actually only significant for a longer trip distance, if there would be two drivers in the combustion-engined vehicle taking turns while eating in the car.

With regard to the remaining shortcomings in terms of planning effort, it will be only a matter of time until the car-integrated travel planning tools are sufficiently sophisticated, until an even denser network of fast charging stations with a unified interface for payment is available, and until the price spread for rapidly charged electrical energy closes in to the one we are used to for petrol.

Even though for the planning of this first trip a spreadsheet was involved (and even online accessed and updated while traveling), in the intermediate future we will most probably use instead the mobile phone application APRP (“A Better RoutePlanner”), which we were able to easily customize such that it matched the model and data collected in the spreadsheet.