In an effort to make charging electric cars at home as simple as filling the gas tank, automakers are starting to change the ritual itself. Even before the official presentation of the all-electric Cayenne, Porsche confirmed the development of complex inductive charging technology. Now that the electric Cayenne has hit the roads, the brand is preparing to launch an optional wireless system for all those who want to skip connecting cables at home.
The system is based on a massive 50 kilogram floor plate, which plugs into a wall socket and contains a large transmitter coil. The panel converts AC voltage from the mains to DC, and as the Cayenne is positioned above it, a secondary coil under the front of the vehicle begins to receive power. Porsche states that their technology supports charging with a power of up to 11 kW. It is interesting that, as he notes Jason Fenske from the canal Engineering ExplainedPorsche’s own mobile charger for the US market offers a maximum of 9.6 kW, making the wireless option faster than traditional home charging with a cable.
How does it work and how effective is it?
To make parking as easy as possible, the wireless charger comes with special software within the Cayenne’s Surround View function. The display in the car shows the position of the receiver near the front axle, while the green circle on the ground indicates the position of the floorboard. The driver just needs to adjust the vehicle so that the green dot is inside the circle and charging can begin. For optimal performance, the Cayenne’s air suspension will automatically lower the vehicle to the ideal distance from the board.
Before the start of the energy transfer, the system automatically exchanges data, including the password, in order to prevent possible theft of electricity. Although wireless systems are often considered inefficient, Porsche engineers claim that this system achieves an efficiency of between 89 and 92 percent in real-world conditions, well above the minimum 85 percent required by the current standard. By way of comparison, classic charging via a standard home socket (Level 1) on the Cayenne has an efficiency of only 60 percent, which makes the wireless panel a significantly more advanced option. Interested buyers don’t need to worry about safety either – the floor plate is waterproof and equipped with sensors that detect foreign objects and automatically stop charging if something gets between the plate and the vehicle.
A high price for wireless convenience
Although the system is undoubtedly practical, it is also very expensive. According to available information, the US price is about $6,500 for the floorboard, while installing the necessary hardware in the Cayenne itself costs an additional $1,650, bringing the total cost to more than $8,000 (about €7,500) before taxes. Fenske’s long-term cost analysis shows that the real cost does not lie in the price of electricity at all. After 320,000 kilometers, the difference in the cost of electricity between wireless charging and a classic Level 2 charger is only about $1,000. Given the average annual mileage, it would take about 15 years to reach that difference, which means that the high initial cost of the hardware is the main financial barrier.
It is important to note that this technology will not be available for retrofitting on existing Porsche electric models such as the Taycan or Macan, as their chassis do not have space for the installation of a receiver plate. Porsche’s partner in the development of this technology is reportedly the company WiTricity, one of the leaders in the growing market of wireless charging for electric vehicles.