The Mercedes-Benz EQXX electric car: Efficiency wins out
Seite 2: Losses and solar energy
A big advantage of higher efficiency: less waste heat is produced. The EQXX cools its systems via a plate in the front underbody area. It provides almost no air resistance. A servo only opens the flap to the large radiator in the front of the vehicle when more air flow is required due to high power demands or (probably more frequently) due to increased air requirements of the air heat pump for cabin heating. When we left Sindelfingen, the thermometer showed only 3 °C, for example. The air flows in at the bottom, through the slanted radiator and out of the two shafts in the front bonnet.
Die Technik des EQXX (4 Bilder)
One optimisation point that makes a difference in all vehicle sizes: minimising losses. Here, the Group brand "Mercedes AMG High Performance Powertrains" (HPP) helped with Formula 1 technology know-how. The result was an efficiency of 95 percent for the powertrain including the converter. This is a value that is normally achieved by good engines WITHOUT a converter. HPP also used experience from the (expiring) use in Formula E, where Mercedes' "EQ" racing engines now exceed 98 percent efficiency.
Low voltage suction
With the low consumption of the EQXX, the consumption of the 12 V low-voltage grid becomes interesting for optimisation. Here, the EQXX basically does what the first Nissan Leaf did: it feeds the 12 V grid via a solar panel on the roof. The Leaf's tiny panel only kept the starter battery charged, whereas the 117 cells of the EQXX supply the low-voltage electrical system with electricity even when the vehicle is moving, which does not have to come from the high-voltage battery. Over a distance of 1000 km with the measured consumption, this results in 25 extra kilometres. In series production, a solar panel could additionally charge the traction battery while stationary via a bidirectional DC-DC converter.
Tips for lower consumption
The 12 V consumers include the numerous powerful control units that do many things automatically that used to require range experience in the driver's seat. The EQXX was on the road for long distances with adaptive cruise control, which pays attention to consumption parameters in addition to traffic. In addition to the automatisms, the systems give the human driver tips for better consumption. We know this from EQA to EQS, where it works well. This will also remain an important part of the series production strategy, because it brings more efficiency to the fleet in terms of production technology.
Interesting detail: The EQXX has normal mirrors, albeit slightly smaller than usual. Although a rear-facing camera gets by with less frontal area, the overall saving in the passenger car sector is small because the camera screens need electricity. Together with the questionable performance of camera mirrors in many areas, Mercedes leaves them out, even in this prototype, where questionable performance would have been an option in view of potentially more PR through cameras.
Comparisons at the end
The EQXX was built with Mercedes' series strategy of large cars in mind. That is why it cannot compete with the XL1 or even the Aptera. Whether anything at all in the direction of the Lightyear One will come from Mercedes is questionable in view of the expected sales figures. It's more about building more efficiency into fundamentally inefficient (but lucrative) big cars. The EQS SUV has just been unveiled and shows where the journey is going: to wherever it's going. Perhaps at some point there will be room for a production efficiency vehicle under the "Smart" brand name. Currently, however, with the 1820 kg weight and SUV shape of the Smart #1, things are going in the diametric direction there.
During the demonstration drive of the EQXX, the crew arrived in Cassis after 12 hours and two minutes (including a 30 minute break with driver change and recharging of the support vehicles) and 1008 kilometres. The battery still showed 15 percent charge. The team would still have made about 140 kilometres with it. For me, the EQXX shows less what would be possible in terms of consumption, because Volkswagen or Aptera show that better. Rather, it shows the potential for savings even in larger cars, which was Mercedes' concern. After all, intelligent optimisation only costs money once, when the car is built. After that, it can significantly reduce both the threshold costs and the energy costs. Since these costs lie with the customer, it is up to us to favour energy-saving vehicles. The current spiral of large prestige vehicles means: unfortunately, there is little to favour. Great opportunity for the next generation of the EQA, Mercedes ...
(cgl)