Mercedes Vision EQXX Prototype Review: 747 Miles, 240 HP Is the EV Future We Want

So many EVs focus on massive horsepower. The Vision EQXX prioritizes efficiency above all else. And that’s a great thing.

byJerry Perez|
Mercedes-Benz Reviews photo
Dirk Weyhenmeyer/Mercedes

"It's more than the $3 million you'd pay for an AMG One but less than the $142 million someone paid for the 1955 Mercedes-Benz 300 SLR Uhlenhaut Coupe." That's the line the Mercedes-Benz Vision EQXX lead project manager fed me when I asked about the prototype's cost. The wild-looking EV holds the title of the most efficient vehicle Mercedes has ever built, and I was set to drive it the following day at the brand's proving grounds in Immendingen, Germany. Most test drives are designed to advise consumers on a potential purchase, but not this one. You can't buy this, nor can you buy its technology—yet. This is Mercedes flaunting its brainpower and near-unlimited resources; its way of previewing the future, according to Stuttgart.

And much like the price, the details surrounding the test were intimidating. "There's only one in the world," the project manager went on. ”So remember that as you drive around the track."

Okay, no pressure.

Efficiency Has a New Face

Once the idea for any new car is conceived, it is immediately tasked with meeting multiple objectives. From safety and performance to comfort and luxury, a new Mercedes has to check a lot of boxes before it's rolled out to customers. When the EQXX was greenlit two years ago, however, it had only one goal: to travel 1,000 kilometers (about 621 miles) on a single battery charge.

The team met that goal this April when the car traveled 1,008 kilometers (about 626 miles) in real-world driving conditions from Germany to France. There was a little "problem," however: The car had some range left to spare. So, Mercedes decided to give it another go to completely drain the thing on a follow-up run from Stuttgart, Germany, to Silverstone, England, in June. The car went even further this time, driving 1,202 real-world kilometers (about 747 miles) on a single charge. That's an average consumption of 8.3 kWh per 100 km (62 miles) at an average speed of 52 mph.

Jerry Perez

With a drag coefficient of 0.17, the EQXX isn't the most aerodynamic four-wheeled vehicle ever. That superlative goes to something that looks like salmon fillet on wheels. The EQXX is, however, more aerodynamic than a regulation football (0.19). And its production sibling, the EQS sedan, is currently the most aerodynamic production car in the world. This is important to know because the EQXX's design was always shaped by its mission, not vanity.

Efficiency is slippery, hence the 195-inch-long body that begins with a low and wide face and culminates with a luxurious longtail. Active shutters throughout the car optimize airflow depending on driving conditions, while a special algorithm retracts and detracts a massive rear diffuser as needed. Hidden door handles and aero wheels maximize airflow through doors and wheel wells, while an underbody tray seals the chassis to prevent turbulence. At speed, this equates to a feeling of gliding rather than driving, but more on that later.

Jerry Perez

The EQXX's drivetrain is as bespoke as it gets, with the Mercedes-AMG Formula 1 team chiming in with a lot of components. Engineers were tasked with making the car lighter, stronger, more efficient, and then lighter and stronger again. Although full specs aren't available, the basics are these: a near-100-kWh battery rated at more than 900 volts that produces 180 kW, which translates into 240 horsepower. A rear-mounted motor drives the rear wheels while the fronts focus on steering.

Driving the Vision

I wasn't behind the wheel to break any records. My co-pilot—an EQXX engineer—recited key objectives for the drive, such as a target efficiency of under 10 kWh per 100 km, though I was still trying to catch my bearings after squeezing my large frame into the low-riding prototype. Despite it being a big car with a spacious cabin, the door openings are narrow and the roofline is low. The seat and wheel also have limited adjustability compared to a production car, making it tricky for me to get in and out without looking like a clown.

Jerry Perez

Closing my door took a few tries because they're mostly carbon so they're extremely light and feel fragile, though they're actually very strong. I kept pulling it closed via the pull strap (no door handle) until my co-pilot finally told me to not be afraid and give it a good wham. It worked. All I could think was that yesterday I was told to be careful with it!

I was ready. I shifted into drive via the steering column-mounted shifter and... nothing happened. "Give it a bit of throttle," my co-pilot said. I did, and the car began rolling the way most EVs do, with a tiny jolt forward and an audible clunk of the brakes releasing the wheels.

It took me all of 25 feet to realize this was something special. It felt like I was steering a block of solid aluminum on wheels. Set in the most neutral of three drive gears (more on its complex gear setup later), the EQXX rolled smoothly and without making much of a sound. It wasn't a completely silent experience because of the tire noise and the occasional creak of the chassis or suspension, but compared to a normal EV, most of the electrical whirring sounds were absent.

For a one-off prototype, the interior felt almost production-ready and very much so like a Mercedes-Benz. While it may look transplanted from a swanky Maybach, all cabin materials are actually plant-based and recycled. The faux leather-wrapped steering wheel, seats, and door panels made the EQXX look and feel like it could hit dealerships tomorrow. An enormous single screen serves as a one-stop shop for all of the car's controls, combining drivetrain, media, and informational displays into one. It's a radical take on Mercedes' already huge Hyperscreen, which I previously experienced in the EQS AMG. This one must be a good five feet long, if not more, given that it runs the entire width of the dash.

Once plugged into one of Immendingen's test loops, I was free to give it the beans and see what the EQXX was capable of until I was reminded that outright speed wasn't the car's—nor the test drive's—purpose. That would be efficiency. And that's where the single-speed transmission truly shines. With one click of the left paddle, I shifted into D- (D minus). This meant stronger regen braking when off the accelerator so the car could recapture some energy and boost that key kWh-per-100-km number. As the test loop got curvier, I was instructed to click down even further into D--. This setting is as hardcore as regen braking gets this side of a Formula E car. Lift your foot off the accelerator and you get thrust forward like an unrestrained watermelon. I can confirm the prototype's seatbelts work.

The special Bridgestone tires felt adequate during cornering—given their purpose of efficiency, not outright grip—and were aided by the car's ridiculously low center of gravity. The steering feel was incredibly direct. Monumentally better than any production EV I've driven, including other Mercedes cars. In medium-speed, tightening-radius corners, the front end felt a bit light due to the EQXX being rear-wheel drive and lacking much of anything directly over the front axle. Not to mention I wasn't familiar with the car's handling characteristics, so I took it fairly easy. Dive-bombing into corners in a one-of-one prototype wouldn't have been wise.

The Gliding Trick

There was a specific straightaway that especially highlighted the car's drivetrain and aerodynamic wizardry. At my co-pilot's command, I clicked the right paddle into D-, then D, then D+, and once more to D++. (D++ is the opposite of D--, sort of like first and sixth gear.) I was then instructed to accelerate to 62 kph and take my foot off the pedal. What followed was the oh-shit moment of the drive.

Do this in any normal car and you'd coast for a second or two before you start drastically decelerating. In the EQXX, the car simply kept going, and going, and going. This straightaway wasn't at a decline, either. Cruise control wasn't activated, so the car wasn't sneaking in some forward propulsion. I sat there with my jaw on my lap, watching the speedo remain at 62 kph for nearly a quarter of a mile. This magnificent performance was due to one of the—if not the—most efficient drivetrains on the planet. The EQXX provided a surreal experience more akin to gliding rather than driving.

Winning the Efficiency Game

Back at the garage, program engineers downloaded the car's telemetry and sat me down for a debrief. I tried to tell them I wasn't Lewis Hamilton so there was no need, but they insisted on reviewing the data.

It turns out I drove much more efficiently than I imagined: 7.2 kWh per 100km(!) average consumption. This was better than the 7.9 set by a Mercedes driver during testing, which was pretty amazing, I was told. My average speed was 45.85 kph (28.48 mph) versus their 49.32 kph (30.64 mph), meaning my superb efficiency was a result of my slightly slower speed—but I can live with that. Also, telemetry showed I only used the brake pedal once during the recorded 20-minute run.

Data evaluation overlaps two individual runs. Blue: Jerry Perez. Gray: Test Driver.

It's fair to consider this funky-looking car that Mercedes claims it won't build and wonder what the hell it's for. But look at it this way: the AMG One is a monumental hypercar powered by a Formula 1 engine. It's the pinnacle of Mercedes' engineering prowess and the last hurrah for ICE development. It's representative because it closes a long and very important chapter in the company's history.

The Vision EQXX is the opposite. It starts a new chapter for the three-pointed star. Think of it as an advanced, rolling telescope that looks into the future. Its F1-level technology may be strictly for prototypes today, but Mercedes wouldn't be dumping bags of money into it if it didn't foresee a payoff. More importantly, it's perhaps the first EV from a luxury brand that focuses on efficiency rather than monstrous speed. I mean, 240 hp? That's 511 fewer ponies than the EQS AMG. Heck, it's 693 less hp than the Lucid Air.

Yet, on a road trip, those two would drop out hundreds of miles before the EQXX ran out of juice. That's a future I'm on board with.

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