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Significant factoid roughly two thirds of the energy needed to drive a car on the motorway goes in aerodynamic drag Slash that then efficiency skyrockets Hence the EQXX where a tiny drag coefficient is multiplied by a tiny frontal area to get tiny total drag As it’s electric this means spectacular range The EQXX is experimental but feels plausibly finished and has hit an astounding 750 miles on real roads That’s with a battery of 100 kWh capacity no bigger than some electric SUVs have now and they struggle to beat a third of that range.
The EQXX is no eco slug It gets to mph in somewhere around eight seconds with nice punch out of bends because as with any EV there’s no need for downshifting Rear drive means plenty traction on this dry day and no understeer In fact the test driver says if it’s wet he enjoys using the rear wheel only regenerative braking by paddles to make the back end step outward on the way into bends In the max regeneration setting it’ll pull itself quite vigorously to a stop You very seldom need to touch the brake pedal But when you do it’s firm and decently progressive Better than on a Prius say
The low slung body is lithe in bends far nicer than an EV crossover We have quick accurate steering and little body roll achieved without a rock hard set of springs The body structure feels solid so it doesn’t suck precision out of the steering Most one off test cars are clattery and uncomfortable full of strange grinding and banging noises But the EQXX feels amazingly well developed The motor is smooth the electronics don’t hum and the suspension is refined.
It just sails through the air if you lift off at speed You absolutely can feel the efficiency like a burden lifted from your shoulders The extending rear diffuser cuts the Cd from to but it pops back under the car for slow speed bumps and manoeuvring While admiring this low slung teardrop car I asked Teddy Woll Mercedes’ long serving head of aerodynamics how best to make SUVs efficient Showing the candour of a man about to retire he replied “Ban them”.
But drag isn’t all of it The EQXX team also obsessed on battery efficiency high voltage electrics and motor developing these in partnership with the UK based Mercedes AMG Formula One and Formula E teams The battery holds the same energy as the one in a production EQS limo yet it’s half the size and a third lighter Unusually it’s an air cooled battery pack offering savings in three ways weight and complexity and aero drag through a radiator
Clever detail design in the electronics and permanent magnet motor cuts losses there
and losses mean heat So the engineers surprised themselves instead of having to do a lot of cooling they ended up wrapping the motor and inverter in a thermal blanket to keep it warm They do have a cooling system for hot uphill driving but it’s mostly blanked off saving pump and drag energy Oh and the roof and what would be the back window are covered in solar panels In one sunny day they can add about 15 miles of range
If only it were lighter Yes, 1,755 kg is very little for a 100 kWh car Clever stuff includes thin light castings for the structure and suspension made by biomimicry a reiterative process to make items that look like bones because all superfluous material has been removed by evolution But a BMW i3 was 400kg lighter and roomier inside the EQXX’s rear space is pinched by the narrow low roofline That said the i3 could go only as fifth as far on a charge
The EQXX did Stuttgart to Silverstone plus 11 laps of the track Its average speed was 55 mph and it did 7.5miles per kWh In a normal smallish EV I’d expect to get around 3.2 miles per kWh and need four recharge stops
My EQXX test was two circuits of a mixed course mostly slightly hilly and medium speed Sort of like the Cotswolds except I wasn’t held up by tourist buses First time I just drove like a normal human being and got better than 6.0miles per kWh Then I got competitive Wasn’t actually much slower but remembering my way around the course I knew where I could safely use a bit more speed into a bend while accelerating more gently out of it and where I could best use momentum through hills and valleys That gave me a pretty staggering 7.6 miles per kWh Enough for the said 750 miles’ range.
Many EQXX innovations will show up in Mercedes’ next generation of compactto medium EVs a platform called MMA from 2024 onwards Whether Merc builds a car that looks like the EQXX is less sure It would have compromises on space and practicality compared with a taller hatchback or the crossovers everyone wants to buy.
“ON ONE CHARGE, THE EQXX DID STUTTGART TO SILVERSTONE, PLUS 11 LAPS OF THE TRACK”