Mercedes and BMW will be the first
big names to launch electric performance cars. Evo assesses what they have to
offer.
It's finally happened. After the endless
tedium of fantastical concept cars offering zero emissions and stunning (and
completely unproven) performance, the fully type-approved electric supercar is
upon us.
This is the Mercedes-Benz SLS AMG Coupe
Electric Drive, the beginning of a new beginning. Or perhaps the beginning of
the end, depending on your point of view. What's undeniable is that this SLS is
the most powerful AMG production car ever built. As AMG models don't usually
want for power, that fact is pretty arresting. Yet that's just one of many
surprises this car has in store.
Mercedes
and BMW will be the first big names to launch electric performance cars
Firstly, let me feed your cynicism. Yes,
the Electric Drive has 740bhp and 737lb ft, but it also weights 2110kg, which
is 560kg more than the 622bhp SLS AMG Black Series (see Driven, page 28). The
SLS ED costs around $540,000, depending upon the exchange rate (the car is only
available in left-hand drive, but Mercedes will arrange to get one for you in
the UK), compared to about $345,000 for the Black Series.
Then there's the sticky subject of range.
Driven to EC consumption cycle standards, the Electric Drive can cover 155
miles between charges. It takes three hours to replenish the batteries if
charged through a special (optional) 22kW wall box, or 20 hours through a
normal three-pin plug. Of course, should you want to feel the full force of
737lb ft, that figure plummets. And I mean really plummets. AMG admits that the
ED can run two full laps of the Nurburgring but no more. Put like that,
internal combustion looks safe for a while yet.
But to dismiss the Electric Drive on the
basis of those numbers would be to miss the point. The SLS ED might be
hamstrung by many of the existing EV disadvantages, but it also showcases some
of the advantages of using electric motors in devastating and mind- scrambling
fashion. That is does 155mph and 0-62mph in 3.9sec is by-the-by. That it might
just be the best SLS you'll ever drive is what's really extraordinary...
The
SLS AMG Coupé Electric Drive accelerates from zero to 100 km/h in 3.9 seconds
So how exactly does it work? The basics are
simple. The chassis has a new carbonfibre monocoque incorporated into the
existing structure. It runs centrally from front to rear and houses and
protects the battery pack, which consists of 12 modules, each containing 72
lithium-ion cells. The battery was developed by Mercedes AMG High Performance
Powertrains at Brixworth in Northamptonshire, the same place that makes engines
and KERS units for Hamilton and Rosberg. Up to 40 engineers worked on the SLS
ED project just to develop this battery pack and many of them crossed over
directly from F1 KERS duties.
The battery is said to have a working life
of at least ten years, and it feeds four electric motors (weighting 45kg each)
mounted above the monocoque, two in line with each axle. This means each wheel
is powered individually to create a four-wheel-drive system with unique
flexibility. Each wheel can be accelerated or electrically braked to constantly
make the most of the tire’s grip and manipulate the handling balance, a system
called AMG Torque Dynamics.
My time in the SLS ED is limited to haft a
dozen laps of a short circuit in the northwest corner of Paul Ricard in France.
It's a tight, technical layout and there's a chicane along the only real
straight to further highlight the torque-vectoring systems. Just watching the
Electric Drives circulating while I wait my turn is fascinating; there's no
engine noise at all, just the whoosh and shriek of tires, which is deeply
strange. But just as astonishing is the lack of wheelspin and this SLS's
balance: front tires pinned to the apex and the rear axle hung out at a fixed
angel of attack. If Sébastien Loeb drove an SLS - any SLS - this is how you'd
imagine it would look. Clinical and slightly awe-inspiring.
To
ensure maximum safety, the SLS AMG Coupé Electric Drive makes use of an
eight-stage safety design
So you jump into the ED and it feels like
any other SLS. You sit low, huge bonnet outstretched and mostly out of sight,
rear wheels just behind your hips. There's an engineer in the passenger seat
who explains the car's different modes: Comfort, Sport and Sport Plus. We'll
start in the Comfort, where you only get 60 per cent of the available power, a
smooth-edged throttle response and a layer of foolproof under-steer. Then, a
lap or so in, we'll wind it straight up to Sport Plus and sneakily turn off the
ESP, too. The full might of the electric motors is unmissable, but I want to
know what happens when you bullishly charge beyond the tires’ limits with all
that clever and infinitely adjustable torque-vectoring tech. The engineers is
happy to indulge me and so I hit the Start/ Stop button.
