Ultra-efficient vision of the future of electric vehicles, test driven

There is exactly one Mercedes EQXX, and we were lucky to be able to drive it around a test track in southern Germany this week. This is a special car for a number of reasons, but in short, it’s a highly efficient 100 kWh electric car with a slippery drag coefficient of 17, and 600 watts of solar panels on top.

One look at the Mercedes EQXX, and it’s clear that a lot of thought has been put into it, inside and out. Not only was it designed to be ultra-efficient, it was designed to be a show car – a car that exudes the future of the Mercedes brand.

With the form factor left alone for a minute and the focus on function, this is a solar powered car, very similar to the Lightyear being developed for sale in the Netherlands by Dutch entrepreneurs.

The rooftop and rear window area are filled with solar panels. Mercedes engineers told me they could have made the front cover and the rear and side solar panels too, but it wouldn’t have looked like a car—specifically, a Mercedes. And the benefits of getting that much solar power for the extra weight of panels and wires may have made the benefits moot. The solar panels only convert to 12V power and do not transfer to a 900V drive system – another weight-saving measure. But also, you can get rid of the dream of going back to your car after leaving it in the sun for weeks on a full capacity battery.

Basically, the best you can hope for here from a solar perspective is for the sun to power all of the indoor 12V systems. The 920V system, which includes not only the power train but also the heat pump, must be powered from batteries.

EQXX Drag from .17 is a big exception

Drag is the amount of force exerted on a vehicle through the air flow, measured by the “drag coefficient,” where lower numbers mean the car glides better through the air. With increasing speed, drag becomes more significant and a greater percentage of the total power loss. A Hummer or Land Rover Defender will have a high score of 0.6, a typical car will be 0.3 – .4, and a car with high aerodynamics will be 0.2 – .3.

Even compared to the similarly shaped Lightyear One .19 cD, the EQXX’s traction is on another level – and most impressively, it was achieved with no need for a rear compartment cover like other low-drag vehicle designs such as the LightYear, GM EV1 or Volkswagen XL1 in photo below; All with a drag coefficient of .19.

Other popular low-drag cars are the Tesla Model S Plaid with a score of .21 and Mercedes’ own EQS with a score of .20.

One way to overcome drag was to build ducts for “air curtains” that encase the front wheels, then send that air through the side of the vehicle with additional ducts behind the front wheels. On the hood there are two additional channels that take air from lockable intakes at the front of the car and spit it over the top of the car after using the air to control the temperature.

Interestingly enough, high-density silicon anode batteries do not require active cooling, instead relying on a long, smooth underbody as a heat sink. This not only saves energy in cooling and pumping fluids, but also weight.

Interestingly, Mercedes went with traditional side mirrors rather than cameras, noting that the side mirrors were the most slippery ever. A side effect of this is a small mirror surface, which is combined with a solar panel covering where the rear window would have provided a dimmer rear view.

Low rolling resistance EQXX

Air intake accounts for about two-thirds of a vehicle’s overall energy use – and increases with speed – but it’s not the only factor. Rolling resistance caused by tires facing the road and mechanical friction inside a vehicle can account for up to 20% of the force needed to propel the vehicle. Mercedes engineers gave EQXX ultra-thin tires to work around some of this and spent a lot of time making sure that friction could be eliminated on every moving part. Small tires will have some effect on handling, especially on slippery surfaces.

EQXX High Voltage – Thinner Wires, Less Resistance, Less Weight

While most electric vehicles including Mercedes’ current lineup of electric vehicles use 400-volt systems, the EQXX uses a 920-volt system. According to Ohm’s Law, higher voltages mean less resistance and the ability to use thinner, lighter wires. An added benefit would be faster charging, but Mercedes has decided to keep the charging power relatively low so you don’t have to add the weight of the battery cooling system that needs to cool the fast charge cells. However, higher voltage means less weight and energy loss.

Light weight and large battery mean low power and low charging

Since the EQXX is 1755 kg / 3900 lb “light” and is very slippery in the air, this means that much less energy is required to propel it forward. With a motor of only 180 kW, the EQXX is capable of “rocketing” forward at 100 km/h in less than 7 seconds. The top speed is also unnoticeable at less than 90 mph or 140 km/h. These lower bars are measures to save energy and heat.

Likewise, the EQXX only charges 140 kW. I say “only” because a 100kWh 920V system can easily double that power with a powerful (and therefore heavy) cooling system. But since each watt-hour of added power takes the EQXX more than twice the range of most EVs, the net result is a whopping 186 miles of range in just 15 minutes (not that charging is something this thing needs to do often).

EQXX محرك Engine

Mercedes put together a course at the Immendingen test yards to challenge journalists to see how low a KWh/Km score we can achieve; We first took a tour around the track in an EQB equipped with an EQB train called ‘EMMA’. It felt very prototypical and boisterous, but we got used to the different renovation levels and the track.


Then we got to EQXX.

The car itself is very small inside, and I cloned my head upon entering; It feels very low to the ground and the track felt rough especially for Mercedes, probably because of the narrow tyres. The interior is modern and beautiful and feels very “EQ” with white accents and neon lighting. There’s a loop doorknob and a herringbone rug, and the stuff is all made with cute stuff like sponges and mushrooms.

EQXX drives very easily.

The huge screen inside looks like a huge sucking battery, but it’s an OLED screen, which actually turns off the LED lighting in its black backgrounds. It looks absolutely stunning, especially with some unique driving dynamics built by UI Mercedes.

UI/UX im VISION EQXX: Das Benutzererlebnis im VISION EQXX katapultiert uns in eine intelente, softwaregesteuerte Zukunft. Mit einem beeindruckenden Design und intuitiv bedienbar erstreckt sich das erste komplett nahtlose Presentation in einem Mercedes-Benz uber 47,5 Zoll von einer A-Säule zur anderen.
UI/UX in VISION EQXX: The user interface and user experience within the VISION EQXX propels us into a highly responsive, intelligent, software-driven future. Stunning in appearance, intuitive to work with and in tune with the human mind, the first ever fully seamless head-up display in a Mercedes-Benz extends over 47.5 inches from A-pillar to A-pillar.

Some of the cooler lists will show us where the sun is and how much energy it provides. There is also a lot of excessive nerd porn letting the driver know how much energy is being used in different ways.

Der Effizienzassistent unterstützt die Sinne des Fahrers und berücksichtigt sogar die Richtung und Intensität von Sonne und Wind.
The Efficiency Assistant enhances the driver’s senses, even considering the direction and intensity of the sun and wind.

Mercedes engineers got around 8.5 kWh/100 km in test drives of the EQXX on real roads and motorways from Stuttgart to Cassis in France and Goodwood in England. With my one-pedal driving experience over ten years of driving electric vehicles, I thought I could set a record. Unfortunately, I ran into two stops while driving for the other cars on the track and only ended up in the middle of the pack with a total of 8 kWh/100 km. For this, I got a post shield certificate (!!). Toshi.

Das UI / UX im VISION EQXX bietet ein neues Maß Digital Luxus. Es liefert den Insassen die Informationen, die sie brauchen. Und zwar genau dann, wenn sie sie brauchen – nicht mehr und nicht weniger.
The VISION EQXX’s UI/UX delivers a new level of digital luxury, providing passengers with the information they need when they need it – nothing more, nothing less.

EQXX – Not for sale, but Mercedes engineers want it to be a product

The EQXX is designed not only to be a tech show to the world, but also to let the company know what electric interior cars can come with. Every engineer I spoke to said it was a learning experience that would cross over to other vehicles. So, both internally and externally, EQXX was a huge winner.

But more than one engineer has asked me to try and rally public support to make the EQXX an actual product.

This got me thinking.

What you need to do for the EQXX to make it a production car – thought experiment:

  1. I would like to cut the battery in half to ~50 kWh. This will also significantly reduce weight not only in the battery, but also the frame and components, making it more efficient. So instead of 750 miles of range, we’ll say 420 miles. Also it would lower a lot of cost.
  2. This means that at a charging speed of 140 kW, it will be over 200 miles in 15 minutes
  3. Roll It Up – Put solar panels all over the car and make those panels capable of charging a 920V package and driving the motors. Instead of 600 watts at peak, we are now over 1,000 watts. Range closer to 70 km per day from the sun. Park the car in the sun for a week at the airport? Return to a full battery.
  4. Much lighter weight but the same motor means 5 seconds 0-60 times faster.

I’m starting to realize I’m building a $250,000 Lightyear Zero, or maybe trying a Mercedes, something a little faster, better, and…cheaper? Perhaps Mercedes should keep an eye on the Dutch team in the north. vice versa!

ISION EQXX Driving Experience @ Immendingen

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