Mercedes-Benz goes the distance with EQC

MERCEDES-BENZ has gone to extreme lengths to ensure its first-ever all-electric series production model, the EQC mid-size SUV, is capable of seamless operation and charging in any conditions, thanks to an exhaustive testing program.

With about 2.5 million kilometres of testing clocked up across 400 test vehicles, the EQC has covered twice as much distance in its development phase as an internal-combustion model from the German car-maker.

Speaking to GoAuto at the EQC international first drive in Oslo, Norway, Mercedes-Benz project manager of EV Christian Pfeffer said one of the biggest reasons for its comprehensive test program was the need to evaluate charging capabilities as well as driving.

“On a conventional car, the most important thing of testing is driving,” he said.

“Now with an electric car, there is driving and charging. And you have this connection with the infrastructure which you also have to test.

“And so in our test program, this was a big task to test all of the infrastructure all over the world. So, we went to Japan, we went to China, we went to Norway, to Sweden, to South Africa, to the States, not only for driving but also for testing the infrastructure.”

Mercedes also had to test the power grid in different countries, which use varying levels of voltage. Different brands of charging stations are also used across the world.

Just as important as ensuring faultless charging ability is was testing of the thermal efficiency of the powertrain, with Mercedes travelling all over the world to hot- and cold-climate areas to ensure the battery-electric powertrain can perform at peak levels in any condition.

Much cold-weather testing took place in Sweden, with Mercedes conducting a road trip from Stuttgart to Sweden via Norway to test both the car performs in cold weather and with the existing EV infrastructure in Europe.

“In most cases, in most test drives, we fly our cars to Sweden and got for testing there, but for this car, we drove up in order to see how the car works in the environment, with our charging systems, to see how does the infrastructure work together with our car systems,” said Mr Pfeffer.

“And we want to see how you can handle it to drive from Stuttgart to Sweden.”

Extensive hot-weather testing was also conducted to ensure the cooling systems of the cabin and powertrain both worked perfectly with no loss of power.

“So we took a lot of time in southern Spain and South Africa to optimise the cooling system, it is not only to bring a high level of thermal comfort, but to also ensure you have no de-rating on batteries and electric motors, that you have the same power,” said Mr Pfeffer.

“It was also to get a high efficiency to the drivetrain – this was one of our main topics to bring all climate zones to a high efficiency to the drivetrain.”

With 760Nm on tap from the moment the accelerator is pressed, Mr Pfeffer said Mercedes had to strike a balance between offering a car with a stiff-enough chassis to ensure full performance while also providing a comfortable ride befitting of the three-pointed star brand.

To do so. the company developed algorithms to best provide a mix of maximum traction, performance and ride comfort, testing in a range of conditions including on slippery, icy roads in Sweden.

The testing program for EQC commenced four years ago and has been made up of a mix of real-world hardware testing and lab simulations as well as digital testing for the car’s software.

When asked whether each new EQ model will require the same level of exhaustive testing as the EQC, Mr Pfeffer said the company would apply the same learning where possible, but each testing program will still require plenty of unique development with different powertrains and layouts for different models.

“It depends on the parts, but we can use a lot on some parts,” he said.

“But we’re always having this high standard, and we want to ensure our components work in the system of a specific car perfectly.

“So, it’s not like, ‘OK, put this drivetrain in another car and it will be OK’, no, it has to be perfectly set up, the perfect application and tailor-made for every car.”