Electric SLS: High-voltage performerComment on this story
Paris Motor Show - It could only have come from Affalterbach: the world's fastest, most brutal electric car and the most powerful AMG yet.
We don't care if you think battery cars are for wusses - show some respect for Mercedes-Benz' SLS AMG Electric Drive, with four electric motors delivering a total of 552kW and 1000Nm, capable of accelerating from 0-100km/h in less time than it takes you to read this paragraph.
3.9 seconds, to be precise.
Wheel-selective all-wheel drive allows the car to deliver maximum torque to the wheels with the most grip while Kers technology borrowed from Formula One helps the high-voltage battery pack cope with the demands of amp-hungry motors.
Unlike with a combustion engine, the build-up of torque is instantaneous with electric motors - maximum torque is effectively available from a standstill, accompanied by total lack of vibration, for a truly 'electrifying' take-off .
The four electric motors, weighing 45kg each and revving to 13 000rpm, drive all four wheels individually through an axially-arranged transmission, normally only possible with wheel-hub motors, which have the disadvantage of generating considerable unsprung weight.
Each individual wheel can be both electrically driven and electrically braked, depending on the driving conditions, thus helping to reduce oversteer/understeer, increase yaw damping, reduce steering effort and increase traction.
It offers the driver three transmission modes: Comfort (comfortable and forgiving), Sport (sporty with balanced driving characteristics) and Sport+, with the accent on agility.
THE SOUND OF MOVING
On every other electric car all you hear is a low-speed growl that becomes an irritating whine as the speed rises, but not this one. The power junkies at Affalterbach have invented a sound-track to match the muscles of this extraordinary golf-cart.
It starts with characteristic start-up sound that rings out when you press the “Power” button on the console, then produces a tailor-made sound for each driving situation: dynamic when accelerating, subdued when cruising and equally characteristic on the 'overrun'.
The sound is not only dependent on road speed, engine speed and load conditions, but also reflects the driving situation and the vehicle's operating state with a suitable driving noise.
It's a combination of the composed sound, the use of the car's inherent noises and the elimination of background noise, referred to by acoustical engineers as “sound cleaning”, and it comes to you courtesy of the standard, 11-speaker sound system.
HALF A TONNE OF ELECTRONS
The liquid-cooled 400V battery pack consists of 12 modules each comprising 72 lithium-ion cells, it weighs 584kg and is rated at 60kWh - which means it can deliver 60kW continuously for an hour, or a maximum of 600kW for six minutes.
But the SLS Electric Drive is electronically limited to 250km/h, so even if you point this car down an autobahn and floor it, it will run a lot longer than that before it runs out of juice.
Then you'll need to recharge it, which takes about three hours using a special 22kW 'charge box' (which comes with the car) fitted in your garage - if your home has three-phase power, that is. If not, you can plug it into a standard 220V socket and wait about 20 hours.
The battery pack lives in a carbon-fibre box that acts as the 'spine' of the chassis, bolted and bonded to the aluminium spaceframe body. The four electric motors and two transmissions are mounted close to the wheels and very low down in the chassis to keep the centre of gravity as low as possible.
NEW FRONT AXLE
The Electric Drive is also the first SLS Gullwing with all-wheel drive so, instead of the double-wishbone set-up of the V8 version it has motorsport-derived multi-link independent front suspension with pushrod damper struts, to make way for the front drive shafts.
Ceramic composite brakes are standard - 402 x 39 mm at the front and 360 x 32 mm at the rear - for reduced unsprung weight more direct steering response, especially on long high-speed sweeps.
The SLS Electric Drive comes with a special carbon-fibre front splitter, darkened headlights, special badging, a new diffuser-look rear apron and five-twin-spoked, 19” alloy rims with 265/35 tyres on the front and 295/30 at the rear.
AMG sports seats and lots of carbon-fibre trim elements set off the interior, and behind the new AMG steering wheel there is a special MG instrument cluster with, instead of rev counter, a power display showing power requirements, recuperation status, transmission modes and battery charge.
The Mercedes-Benz SLS AMG Coupé Electric Drive will go on sale in Germany in 2013 at €416 500 (R4.4 million).