Logging 747 Miles in Test Run, Mercedes EQXX Basks in EV

  • One might consider driving the EQXX to be unremarkable, although it instills confidence when the driver sees how many miles lie ahead before recharging.
  • Relative to the Mercedes EQS’s 107.8-kWh battery, the pack in the EQXX is half the size and 30% lighter.
  • The next task for the EQXX development team—a daunting one—is to adapt its advanced technologies to series-production EVs, which means taking out loads of cost.

    If cars were like professional athletes, they would be voted in to their respective halls of fame by blue-ribbon committees of designers, engineers, executives, and journalists, and there might be a required waiting period of a certain number of years after production ends for a particular vehicle to become eligible.

    At Mercedes-Benz, its Vision EQXX high-mileage electric concept car is certain to be a first-ballot honoree, perhaps even earning its place at the company museum in Stuttgart purely by consensus, without even taking a vote. Museum curators probably already know which exalted place of distinction is best suited for this uber-efficient four-door with the wild interior, solar-panel roof, thin tires, and a back end curiously sloped like that of the Shelby Daytona Cobra.

    It’s more aerodynamic than an American football, with a coefficient of drag of an astounding .17, aided by slender, wind-cheating side-view mirrors. Aerodynamics might be more important than you think: A typical EV today dedicates almost two-thirds of its battery capacity to cutting its way through the air ahead.

    The EQXX is barely two years old, and yet it has demonstrated that EVs can be sexy, comfortable, and functional, all while delivering more than 621 miles of range on a single charge—way better than a typical internal-combustion vehicle running on a full tank of gasoline and rivaling the most efficient diesel engines, before they were sullied and banished by a scandal that started 325 miles away in Wolfsburg.

    Mercedes-Benz Vision EQXX.

    Mercedes-Benz

    It’s the powertrain that makes the EQXX truly special, as evidenced by a brief test drive of this one-of-a-kind prototype at Mercedes’ proving grounds in Immendingen south of Stuttgart. It was designed for efficiency rather than hold-on-tight acceleration, and yet the 241-hp EQXX gets up to speed quickly and can be paddled for friction-free sailing or—the opposite—one-pedal driving to regenerate the battery. This is not a slam at all, but the drive experience was completely unremarkable, moving this four-door four-seater as confidently as other EVs now in the market.

    But the EQXX surely instills more confidence when the driver sees how many miles lie ahead before recharging. Who needs range anxiety?

    mercedesbenz eqxx

    Mercedes-Benz Vision EQXX interior.

    Mercedes-Benz

    In April, the product-development team juiced up the car’s nearly 100-kilowatt-hour battery pack and drove 626 miles from Sindelfingen near Stuttgart through the Alps to Cassis on the southern coast of France, at an average speed of 54 mph. There was no recharging along the way, and upon arrival the car still had juice to drive another 87 miles.

    Emboldened by this success—and eager to get more fan love from European motorists who saw the EQXX on public roads and wanted to know everything about it—the team planned another jaunt two months later. This one started in Stuttgart and headed northwest, crossing the Chunnel into the UK and meeting up with the Mercedes-AMG Petronas Formula One team in Brackley en route to the Silverstone race track, where Formula E driver Nyck de Vries logged 11 hard laps (at a top speed of 87 mph) as the car finally ran out of electrons in the pit lane. This trip totaled 747 miles on a single charge, with an average speed of 52 mph.

    mercedesbenz eqxx

    Mercedes-Benz Vision EQXX battery pack.

    Tom Murphy

    For context, the Lucid Air EV now available can deliver as much as 516 miles of EPA-estimated range, or 4.6 miles per kWh of electricity—it’s one of the most efficient cars ever to see production. The Lucid Air also has a larger 112-kWh battery compared to the EQXX.

    And yet on a consumption basis the EQXX beats the Lucid Air handily, driving 7.5 miles on each kWh of electricity in the June drive to the UK.

    mercedesbenz eqxx

    Mercedes-Benz Vision EQXX.

    Mercedes-Benz

    These days, any EV that consistently delivers better than 3 miles per kWh is considered efficient. The Tesla Model 3 RWD also would be in the running for the most-efficient car title—often seeing 4.5 miles per kWh. This Tesla is rated by the EPA at 132 mpg-e (1 mpg-e better than the Lucid Air) with a much smaller battery capable of 60 kWh of capacity and a range of 272 miles.

    Perhaps most remarkable about this EQXX experiment is that the car isn’t running on next-generation supercapacitors or solid-state batteries but instead on an optimized lithium-ion architecture rated at 920 volts. But the automaker considers its air-cooling of the module, as well as the battery management system and overall packaging, to be groundbreaking.

    With Formula 1 thinking, Mercedes’ battery chemists squeezed the energy of the larger EQS all-electric sedan into the dimensions of a compact car. Relative to the EQS’s 107.8-kWh battery, the pack in the EQXX is half the size and 30% lighter. The EQXX uses active cell balancing, which means drawing energy evenly from the cells, giving it greater stamina. The battery weighs 1091 pounds, including its electronic controls.

    You’re probably reading this wondering, why doesn’t Mercedes just produce this EQXX that could rapidly accelerate the arrival of the tipping point for electric vehicles over conventional gasoline ones?

    mercedesbenz eqxx

    Vision EQXX’s thin side-view mirror.

    Tom Murphy

    It’s not a simple answer. The engineers got to throw every weight-saving idea at this development project because Stuttgart’s goal was a concept car that could drive at least 1000 km (621 miles) on a single charge, no matter the cost. Engineers rarely ever hear those last four words, so the ideas came pouring in.

    Many of the lightweight strategies got baked into the finished product, such as the ultra-thin solar roof, a subframe derived from Formula 1 racecars, a lightweight battery case, doors made of carbon- and glass-fiber reinforced plastics, aluminum brake discs (in place of cast steel), glass-fiber-reinforced plastic springs, and magnesium wheels wearing slim tires optimized for ultra-low rolling resistance rather than grip.

    mercedesbenz eqxx

    Mercedes-Benz Vision EQXX.

    Mercedes-Benz

    With so much moonshot technology onboard, it’s no surprise the development team hesitates to put a pricetag on this futuristic prototype. Think seven figures.

    The EQXX weighs in at 3858 pounds, which is svelte compared to the latest EVs such as the Mercedes EQS (weighing up to 5952 pounds), Cadillac Lyriq (up to 5915 pounds), Lucid Air (up to 5236 pounds), Audi e-tron GT (up to 5060 pounds), and the BMW i4 (up to 5018 pounds). Certain versions of the similarly sized Tesla Model 3, with its much smaller battery, actually undercut the EQXX, at 3648 pounds, while others balloon up to 4250 pounds.

    mercedesbenz eqxx

    Mercedes Vision EQXX seats.

    Tom Murphy

    The new drivetrain—designed and built in-house—achieves what Mercedes-Benz describes as a benchmark: 95% of energy makes its way from battery to the rear wheels. This compares to 90% efficiency for the production Mercedes EQS, and about 40% for the most efficient internal-combustion engines.

    Because the drivetrain is so efficient, it generates minimal waste heat, which means the thermal-management system can be extremely small and lightweight, while aided by aero-shutters, coolant valves and water pumps. There’s also a cooling plate in the floor to take advantage of air flowing underneath the car—keeping the drive unit cool and even extending range by about 12 miles in the most aerodynamic mode.

    mercedesbenz eqxx

    Thin tires on magnesium rims for Vision EQXX.

    Tom Murphy

    With a top speed under 90 mph, the EQXX clearly was designed to maximize range rather than satisfy thrill seekers. At that pace, the car would rarely venture into the left lane on the autobahn, but for most Americans on the highway a car with this much power would be more than adeqauate.

    The entire EQXX program went from the drawing board to the road in just 18 months. This all-electric unibody halo car sets the template for Mercedes-Benz’s future. The next job—a daunting one—is to adapt these technologies to series-production EVs, which means taking out loads of cost.

    mercedesbenz eqxx

    Vision EQXX has F1-inspired subframe.

    Tom Murphy

    And yet, during last week’s media demonstrations at the track in Immendingen, the mood among the young team that developed the EQXX was upbeat and lively—even electric, one might say. They must see the potential.

    Mercedes-Benz spent a lot of money developing its Vision EQXX concept car, but do you think its technologies will help extend range for future production EVs? Please comment below.

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