A new power has just been added to the technical sheets of electric cars: that of fast charging. Sufficient to establish a hierarchy between the models, this value is sometimes abstract, and can even mislead. Explanations.
To attract customers, manufacturers have always put forward the technical sheets of their car. And in particular the maximum engine power, which generally makes it possible to roughly anticipate the level of performance of a model, but also to draw up a hierarchy between them. But depending on the mechanical configurations, and therefore the distribution of mechanical energy, two cars of the same level may not offer the same character. Nothing that will change the face of the world in itself, whether for thermals, or electrics, when we talk about peak power.
If electric cars do have a maximum power always communicated by the manufacturers, the administration distinguishes the latter from the maximum net power, also called nominal power. More specifically, it is the energy produced by the traction chain (motor(s)+battery) for 30 minutes, which is indicated in box P.2 on French registration cards. And it is generally very far from the peak power due to electrical technology: we generally observe a difference of 50% between the two values. The proof is with the Volkswagen ID. buzz, latest novelty tested by us, which then presents on its gray card – which is always checked – a nominal power of 70 kW (95 hp) instead of the 150 kW (204 hp) peak. This can also be seen with the Tesla Model Y Performance, with 155 kW (210 hp) instead of the peak 312 kW (424 hp), as revealed by official documents in our possession.
Modest recharge powers fare best
But electric cars have added a new feature to their data sheet, which can then serve as a sales argument on its own: fast charging power. If it is timidly associated with a recharge time of up to 80% charge, the value communicated is no less than a peak located somewhere on the curve. But unlike the power of the vehicle, there are no rules. And this is the problem, since differences exist between the announcements and the power delivered over a given period. Hence this article.
During the Supertests, we decided to screen each vehicle on different charging exercises, varying the type of terminal and networks. And this in order to acquire the maximum of data and to understand what is hidden under the electrical floor. Thus, we determine for each car the average charging power between 10 and 80% charge, depending on the standard curve used. Faced with the differences observed, we calculated the differences between the performance suggested by the announced peak, and the average power actually available on a useful full tank. And as always, there are good surprises and less good ones. Even very bad ones.
Because no, a higher charging peak will not necessarily allow you to leave the station faster for an equal amount of energy delivered by the terminal. It is still necessary that this power can be maintained, at best, throughout the load exercise. This is what electric cars manage to do at the lowest powers. Thus find themselves on the podium three models with less than 100 kW announced with, in order the Kia Niro EV, the Aiways U5 and le break MG 5.
Victory for the Korean compact SUV which, despite its announced 72 kW, manages to maintain an average power of 65 kW. His secret? An observed peak power higher than the advertised peak. But also a better maintained curve as we saw during its Supertest. The Aiways U5, a little faster to reload, gets away with a -11.1% difference, while the MG 5 takes third place with a -14.9% difference between its peak value of 87 kW and its observed average of 74 kW. With lower powers, the batteries are thus less stressed. This allows them to maintain a rather flat curve or, at worst, present a staircase with distinct, stabilized steps.
The paradox of high DC powers
What the cars with the strongest powers announced have obviously struggled to do: among the last five are three cars giving hope of expedited recharging with more than 200 kW! Two reasons explain this phenomenon. On the one hand, it’s mathematical: with high starting values, the differences quickly skyrocket. This is why the new Tesla Model S Long Autonomy, which we were able to measure exclusively, is among the worst students (- 42.40% difference). However, its charging curve is pleasant with a power of 250 kW retained for almost 7 minutes, up to a charge rate of 40%.
But it is on the other hand technical, not all cars being able to maintain such high power for long, whether for technical constraints or by choice in order to preserve the longevity of the batteries. The fact remains that it is the Tesla Model Y that wears the dunce cap of this ranking: proudly announcing a peak at 250 kW, the SUV finally presented a “nominal” power of 105 kW in our hands. . This corresponds to a difference of – 58%, by far the highest, behind that of the BMW i4 eDrive40 (- 43.4%). Their common point? A precocious temperament, with a curve that puts the package at the start of the exercise and not for long enough.
A trait shared with le Ford Mustang Mach-E, which displays the same curve profile. But with an official peak of 150 kW, this American SUV limits the difference to – 34%. It is clear that the stronger the power, the more the curve lacks endurance. The Renault Mégane e-Tech is then an exception here, but it confirms that, as the famous slogan says, ” Without mastering the power is nothing “.
The Hyundai Ioniq 5 and Nissan Ariya keep their promises
However, the Nissan Ariya, which shares its CMF-EV technical platform with the compact, is very different. All of the month in its 87 kWh version, whose performance is notable. Looking good with a difference of – 18.5%, it also manages to climb among the best averages with 106 kW. And remember that the Japanese SUV has never been able to exceed the 115 kW mark, against the promised 130 kW, which might have earned it first place in this ranking. This place is occupied by la Hyundai Ioniq 5, which accumulates praise: its average charging power of 176 kW is the highest in the ranking, and does not deviate so much from the 220 kW promised at peak. These are the two vehicles that best combine absolute (nominal power) and relative (difference with the figures announced) values, while the Aiways U5 has nothing to be ashamed of with a third place in the accumulation of points.
Through this prism, it is the Tesla Model Y which disappoints the most, with a recharging performance implied by its peak of 250 kW which is ultimately only a smokescreen. This puts him at the bottom of the fray, between a Volkswagen ID.3 et un MG ZS EV, when making the overall balance sheet. The Renault Megane e-Tech is also at the bottom of the ranking, with low average power and a very large gap.
Towards nominal fast charging power to better guide buyers?
If the calculation of the power of electric motors is strictly framed by the regulations, the charging power is not the subject of any consideration on the part of the administration. A regrettable choice, since the values announced by the manufacturers can mislead the drivers. The latter would no doubt be more enticed by the reassuring maximum values, rather than by a recharge time of 10 to 80% over a given period which ultimately has no real value: a Peugeot e-208 which requires 27 minutes to make a full from 10 to 80% does not recharge as quickly as a Tesla Model S Grand Autonomie, which needs exactly the same time for the same exercise. Worse still, they might never see the advertised power color depending on the cars and charging rate when plugging in.
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There is currently no bill that would require manufacturers to communicate an average charging power. Because if the engines are already subject to several influential factors, leading some manufacturers to put their reservations on paper, fast charging is even more sensitive: it depends on the charge rate when plugging in, the outside temperature and that of the battery. , or the electrical network. For the same vehicle, charging performance can therefore change rapidly from one terminal to another.
In any case, it appears that it is the vehicles with the most modest powers that best keep their promises. On the other hand, there is a good chance that it is with the cars with the highest advertised powers that drivers will get less for their money.
| Advertised power (peak in kW) | Actual power (nominal in kW) | Deviation of values (in %) | |
| Kia Niro EV | 72 | 65 | – 9,7 |
| Aiways U5 | 90 | 80 | – 11,1 |
| MG 5 | 87 | 74 | – 14,9 |
| Nissan Ariya | 130 | 106 | – 18,5 |
| Hyundai Ioniq 5 | 220 | 176 | – 20,0 |
| Renault Zoe | 50 | 39 | – 22,0 |
| Peugeot e-208 | 100 | 77 | – 23,0 |
| MG ZS EV | 92 | 70 | – 23,9 |
| MG 4 | 135 | 96 | – 28,9 |
| Volkswagen ID.3 | 120 | 83 | – 30,8 |
| Ford Mustang Mach-E IS | 150 | 99 | – 34,0 |
| Renault Megane e-Tech | 130 | 75 | – 42,3 |
| Tesla Model S Long Range | 250 | 144 | – 42,4 |
| BMW i4 eDrive40 | 205 | 116 | – 43,4 |
| Tesla Model Y Performance | 250 | 105 | – 58,0 |