Which models are the most efficient on long journeys?

21 vehicles were tested on long journeys by an independent German body. The Kia EV6 wins this comparison thanks in part to its exceptional charging capacity.

German technology and vehicle consulting firm P3 has embarked on an ambitious task: to determine which electric car is the most efficient on long journeys. 21 models were tested both for their actual consumption and for their fast charging capabilities of the terminals. The result is a study of about twenty pages, a particularly dense one, that reveals an interesting ranking to say the least, in which Tesla painfully integrates into the top ten. Another highlight: for the first time in three editions, a car exceeds the ideal index of 1.0. Indeed, thanks to its ability to restore 300 km of battery life in 20 minutes of charging, the Kia EV6 takes the top spot in the ranking.

The best electric vehicles for travel

Before delving into the details of the comparison, let’s start by looking at the cars that have managed to distinguish themselves. The top 10 rankings are as follows:

The Korean group Hyundai/Kia dominates this ranking with two podium finishes thanks to its two SUVs. For comparison, in our ranking of the best electric cars of 2022, the Kia EV6 and Ioniq 5 also took first and third places. Among other lessons of the rankings, it is worth noting the second place of the EQS, which many observers consider the queen of autonomy with its 107 kWh battery, or the very good place of the Sport Turismo Taycan version, a car that was not particularly praised for its autonomy. As you have already understood, if the ranking contains some surprises, it is due to the research-specific methodology.

How are cars valued?

To understand how the P3 achieves this result, it is necessary to look at the test report set by the partner of the German organization, electrove.com. Indeed, the comparison does not consist of an analysis of the average consumption and charging values ​​of each vehicle, it goes beyond that. The P3 protocol especially appreciates the charging curve of each vehicle, i.e. the change in charging power during the same charging session. Indeed, two vehicles that will have the same maximum load capacity, say 150kW peak power, will not necessarily have the same load curve and therefore the same ability to recover range quickly.
The organization also provides a realistic range estimate for each vehicle tested. This is very different from the WLTP certification, the European standard that most manufacturers report. The comparison refers to the ADAC Ecotest, again a measurement made by an independent German organization of the same name, which is more in line with actual use. All this data is then weighted to arrive at a single measurement index: P3CI (P3 Charging Index).

Although it offers a uniform classification, the P3 organization distinguishes between three categories of vehicles:

  • Luxury cars (from 65,000 euros)
  • Premium cars (from 35,000 to 65,000 euros)
  • Compacts (less than 35,000 euros)

A simple look at the ranking reveals that among the most expensive cars, electric vehicles are often the most durable. Indeed, without exception, all five luxury cars are included in this top ten. On the other hand, only Mercedes manages to break the hegemony of Kia and Hyundai SUVs, two cars with a really interesting price-performance ratio. Indeed, the Ioniq 5 and Kia EV6 benefit not only from proper consumption, but also from record-breaking charging capacity thanks to their 800-volt architecture.

Protocol and its limitations

The test report is necessarily biased, especially when it contains weighing. As advanced as it is, the P3 comparison makes certain choices that should be questioned.
The first concerns average speed. The P3 report uses ADAC data on this issue. However, when testing vehicles, it pays less attention to expressways at speeds of 130 km/h. This is probably why the P3 doesn’t list average speed in its test data, which has a huge impact on consumption. For example, at a speed of 130 km/h on a French motorway, it is reasonable to assume that the average fuel consumption of the EQS will be better than that of the EV6. At least that’s what we found in our own tests.

Then there is the issue of charging. Here, too, the German organization does not indicate in which network and under what conditions the charging phases were observed. But anyone who has ever tried fast charging networks, whether Fastned, Ionity or TotalEnergies, knows that the vehicle isn’t the only factor in determining charging power. The terminal also plays an important role.

Weather conditions are also out of the question in the German comparison, but as we mentioned in our file on the behavior of electric vehicles in winter, not everyone is equal in the face of cold. In more delicate climates, the EV6’s top spot could, for example, be called into question because it doesn’t (yet) have a battery preconditioning mode.

Finally, the study ignores some of the equipment of each vehicle. Indeed, if we take only the Ioniq, which we know well, having tested it for a long time, its autonomy differs by about thirty kilometers depending on whether you choose 19 or 20-inch wheels. However, here, too, all the tested cars do not start on an equal footing.

Should we trust the results of the comparison?

Although it is neither exhaustive nor even methodologically scientific, the P3 comparison is not only a serious indicator, but also a useful one. Its main strength is to highlight concepts that manufacturers report very little on, starting with the charging curve, which is essential to determining the efficiency of an electric vehicle.

On the other hand, complete as it may be, this study should be viewed in hindsight. The importance given by the P3 to the recharging capabilities of each vehicle allows some “poor learners” in autonomy to compensate for their low consumption levels with a large recharging capacity (for example, the Porsche Taycan).
On the other hand, given the difficulty of actually comparing cars in terms of autonomy, the P3’s performance is commendable.

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