the Electra app
the Electra app
Charging stations are the key to using electric vehicles. Electra has decided to offer fast charging stations as close as possible to city centres. The only thing left for you to do is to choose the right vehicle. And when you're not an expert, it's not easy.
Do you need help?
At Electra, direct current fast charging is done either via Combo CCS or CHAdeMO connectors. Combo CCS remains the market leader, while CHAdeMO, a standard that is slowly becoming extinct, is used on the Citroën C-ZERO, Mitsubishi iMiEV and Peugeot iOn (maximum charging power of 50 kW) as well as on the Nissan LEAF (50 kW), e-NV200 and Kia Soul EV (80 kW)¹.
Is the battery the only thing that matters?
Charging speed will depend mainly on the following factors: the maximum charging power supported by the vehicle, which in turn depends on the battery capacity, its SoC (State of Charge), the temperature and the voltage of the battery architecture used by the manufacturer.
Today, while most electric cars have 400 V batteries, the Porsche Panamera, Audi e-tron GT, Kia EV6 and Hyundai Ioniq 5 have 800 V battery architectures, which allow for amazing charging power and speed: with over 200kW of maximum charging power, it is claimed that charges from 10 to 80% can be achieved in about 20 minutes. In physics, based on the formula Voltage V = Current I x Resistance R, increasing the voltage allows to reduce the intensity, and thus the heating of the electrical components. With the same components, the charging power can therefore be twice as high…
In order to protect these components, Korean cars actually do not quite reach 800 V of voltage, which does not always make it possible to achieve the perfect repeatability of the claimed charging performance. Similarly, although the German cars listed above use a converter to go from 400 to 800 V, it is optional with the Porsche Taycan. The theoretical charging performance of the vehicle therefore depends on this option. ² ³
Outside of the 800 V architecture, the latest update from Tesla (400 V) announces a maximum peak power of 250 kW, a power that seems to evaporate very quickly; of the 18-minute charge as with the Ioniq 5, “only” 60% is retrieved.
Note that although the maximum charging power and the battery capacity are important data, they are not the only ones to consider... You should also take into account the consumption and therefore the range of the vehicle! You could get more kilometres back with a car with a lower battery capacity, but with a lower electrical consumption.
In terms of the battery temperature parameter, it is recommended to use the navigation system and plan a charge to turn on the preconditioning / heating system of this battery, which is more and more common in the latest generation of electric cars⁴. Thus, with the battery at temperature, the charge will be optimised. For example, the cells of a Megane E-Tech Electric from LG would have an ideal operating range of 40°C. ³
The opposite problem could be seen on a Nissan Leaf; the battery was overheated on a motorway route, which limited the charging power, well below the theoretical 50 kW, due to the lack of a battery cooling system.
Maximum charging power is good. But good charging power over the long term is better!
…and this is not always how it is! It is normal to observe significant decreases in charging power during a cycle, but this can occur very early on, and sometimes at low charging levels. Thus, as a general rule, it is not recommended to charge beyond 80%, unless you have time to waste. Let's take the example of a Hyundai Kona Electric: it took about 45 minutes to charge from 10 to 80%, and it took almost as long to reach 100%⁵! Here's why: to preserve the battery, and in particular to control the temperature of each of the cells.
For the very recent Renault Megane E-Tech Electric, although the promise of maximum charging power is 130kW, it quickly falls below 100kW after 7 minutes, for a 33% charging level. Charging power is 50kW at 80%³. In some cases, the maximum charging power is only reached under a certain battery percentage threshold, especially with Korean vehicles, under 20% of battery charge (SoC). It is then more recommended to start charging the vehicle below this percentage.²
Thus, fast charging an electric vehicle is based on a variety of parameters that must be taken into account to ensure proper optimisation.
¹Chargeguru.com ² Challenges.fr ³ Automobile-propre.com ⁴ Renault ⁵ Génération-électrique