Electric cars are becoming more and more popular worldwide. Mercedes-Benz decided to keep up with fashions and started working on the SLS AMG Electric Drive together with launching production of the SLS AMG sports coupé. In order to be substantive, in 2010, the company built the SLS AMB E-Cell concept car, which was best remembered for its bright yellow colour.
At the 2012 Paris Motor Show, Mercedes-Benz representatives said that Batmobiles became things of the past, giving place to the new epoch of electric cars represented by the SLS AMG supercar. The 2014 Electric Drive was not much different from its prototype — the E-Cell — thus stealing its way into the hearts of car enthusiasts. This exclusive, utterly powerful production electric vehicle in the Mercedes’s lineup is rivalling such “beasts” as the Ferrari F12 Berlinetta (740 hp) and Lamborghini Aventador (750 hp). The SLS AMG supercar powered by electricity is the second electric model produced by Mercedes-Benz after the B-Class.
POWER OR RANGE
The 2014 Mercedes-Benz SLS AMG Electric Drive produces the total power of 738 hp and can travel around 200 km. However, it’s almost impossible to test both of these characteristics: the SLS AMG is not able to do even two full laps at the Nürburgring at full throttle (the distance of 1 lap is 20 km). And the reason for that lies in the energy management control system.
POWERTRAIN AND SUSPENSION
The powertrain comprises four electric motors — one at each wheel. Each of them can spin to 13,000 rpm, which is essential for a two-tonne vehicle. Unlike the combustion engine, maximum torque is available instantly, right after stepping on the acceleration pedal, providing 1,000 Nm from a standstill. It’s all about the so-called axially arranged transmission, which had replaced the traditional gearbox, as the electric motor produces maximum torque at any rpm.
Each electric motor weighs 45 kg and is powered by a 60-kWh lithium-ion battery consisting of 12 modules, each made up of 72 lithium-ion cells — that’s 864 cells in total — encased in a carbon-fibre box bolted to the car’s aluminium space frame. Battery cells were produced in South Korea. The total weight of the battery together with the cooling liquid and heating element is 548 kg. It is located within a carbon-fibre monocoque in the transmission tunnel and behind the front seats, where the petrol-powered model has the fuel tank. It provides passive safety, low centre of gravity, and well-balanced weight distribution.
The AMG tuning studio was developing liquid-cooled lithium-ion batteries in cooperation with the British company High Performance Engines. The British engineers helped their German colleagues to develop the design of the car and implement the renowned KERS (Kinetic Energy Recovery System) technology used in Formula 1 race cars. At the moment, the KERS technology is used not only by the Mercedes AMG F1 team but by the McLaren and Force India F1 teams as well. Brake energy is transformed into electricity to recharge the batteries. In addition to that, the driver can choose the operating mode of this system like it is done in Formula 1 cars. All software was also developed by Formula 1 experts using the Mercedes AMG High Performance Powertrains technology as the base.
The all-electric coupé features all-wheel drive layout: each engine transfers torque to “its own” wheel, while there are two one-speed gearboxes. Mercedes’s engineers claim this drive scheme to have all the advantages of in-wheel motors, however, it leaves out their major drawback — big unsprung weight, which deteriorates handling and decreases ride comfort. Even though a powertrain like that does not theoretically require any stability control system, the SLS AMG ED still has it and it’s even a two-stage program.
As each wheel is powered individually, the car can boast of both all-wheel drive layout and maximum torque under any conditions, reduced understeer, and lower steering effort. By the way, it also features a new electrohydraulic power steering assist.
In order to compensate for the weight of batteries, lightweight materials — aluminium and carbon fibre — are widely used in the model’s construction. The SLS AMG ED is fitted with carbon-ceramic disk brakes, measuring 402 x 39 millimetres at the front and 360 x 32 millimetres at the rear. They are 40 percent lighter than the regular steel disc set-up and are less exposed to overheating. The standard wheels are 19-inch with 265/35 profile tyres up front and 20-inch with 295/30 profile at the rear.
Its engine is silent like it should be. However, in order to delight the driver’s ear and give a useful cue to pedestrians, the SLS AMG ED is equipped with an 11-speaker system, imitating the sound of a car fitted with a combustion engine.
SPEED
Despite carrying a remarkable amount of electric power, the acceleration performance is rather mediocre: the Mercedes-Benz SLS AMG Coupé Electric Drive sprints from 0 to 100 km/h in 3.9 seconds. Top speed of this all-electric car is electronically limited at 250 km/h. Its range is pegged at 200–250 km and that is just one hour of driving…
CHARGING
Charging this car’s battery is not that fascinating like discharging it. It takes about 20 hours to charge this supercar on a regular 220-volt plug. But as they say, time is money. The owner of this electric vehicle can purchase a high-voltage power station, which enables charging of the all-electric Mercedes-Benz SLS AMG to take place in around three hours.
TRANSMISSION MODES
Speed is limited depending on choosing either of the following transmission modes:
— Controlled Efficiency (С) — an everyday city travel mode. The car will enter the turns reluctantly, give a rather dull steering wheel response, and will behave more like an S-Class than a sports car;
— Sport — provides better velocity performance. Each of four electric motors controls road conditions under “its” wheel individually;
— Sport Plus (S +) — top performance level. Adaptive suspension squats and shrinks, each wheel continues its individual evaluation of road conditions and comes into possession of 185 hp. Even if underestimating the steering angle, full throttle and twisted steering wheel would not lead to oversteer. The outside wheels accelerate, while the inside wheels drop the torque, making the car enter the turn smoothly.
Car handling is improved by systems that control the torque delivered to each of the wheels. When entering the turn, ED’s computers make their own decision on which wheel should be pushed harder and which one should be slowed down a little.
ECOLOGY
The 2014 Mercedes-Benz SLS AMG Electric Drive is the world’s fastest eco-friendly supercar at the time of its official debut. It’s an all-electric vehicle with a zero-emission drivetrain.
RECORD-HOLDER
The Mercedes-Benz SLS AMG Electric Drive electric supercar has broken Nürburgring lap record for production electric vehicles. It covered the distance of 20.8 km in 7:56.234 minutes, which is 12.865 seconds better than the previous record set by the Audi R8 e-tron.
Tobias Moers, Chairman of the Board of Management of Mercedes-AMG GmbH: “For the first time, an electrically-powered series production vehicle circles the Nürburgring Nordscheife in under eight minutes. The record for the SLS AMG Coupé Electric Drive in 7:56.234 minutes on the Nordschleife shows the special position of our innovative and unique drive solution. With the extremely efficient battery technology deriving from Formula 1, four electric motors positioned close to the wheels, the individual wheel torques "AMG Torque Dynamics," the SLS eSound and our ambitious "AMG Lightweight Performance" design strategy, the SLS AMG Coupé Electric Drive generates a breathtaking sensation unlike any other model out on the road”.
By the way, the time of 7.56 sec also belongs to petrol-powered (!) Porsche Panamera Turbo and Ferrari California.
EXTERIOR
The exterior of the SLS AMG Electric Drive is reminiscent of a typical SLS model. But on the inside… In-house AMG Performance Media that features driving telemetry informs the driver about lateral and longitudinal acceleration, tyre pressure and lap time, and also about engine performance and power consumption (kWh/100 km).
The Electric Drive model carries new carbon fibre front splitter, a diffuser, a diamond-look radiator grille, side air inlets, and tinted headlights. Its “breed” is obvious when you glance at the supercar’s profile and the “Electric Drive” badge on its fenders. Based on its overall style, the SLS AMG Electric Drive is fitted with light-alloy 5-twin-spoke wheels.
The major emphasis in the design of the SLS AMG Electric Drive sports coupé is its colour of electric radiance. Its stunning chrome blue colour scheme named the “AMG Electricbeam Magno” was created for this car only and will not be used in other Mercedes vehicles.
INTERIOR
Anyhow, it’s still a sports car and that is why it features sports seats and numerous carbon-fibre trim elements. Behind the new steering wheel, one can find a digital display that replaces a tachometer and speedometer. It provides the driver with all the necessary information. Interior surfaces are wrapped in high-quality dark Designo leather with contrast white stitching.
We have already told you that the Mercedes-Benz SLS AMG ED can produce a roaring sound of a six-litre V8 with the help of audio speakers. The sound is not only dependent on road speed and engine speed but also reflects the driving situation.
The standard SLS AMG ED also features a multimedia system with full high-speed mobile Internet access, pressure gauges for each tyre, rearview camera, and a lap time meter.
PRICE
The promising coupé was supposed to hit the market in July 2013.
The price of the most powerful electric vehicle produced by Mercedes-Benz starts at around €416,500 (including taxes) in Germany. That is $540,000 (just think about it — around half a million dollars!). The price of the regular SLS AMG starts at €186,830 and that is half as much as the “green” supercar.
Those, whose bank accounts are fat enough for a new ride full of adrenaline and comfort, would definitely be able to see the true value of the SLS AMG Electric Drive — a car like no other. A fact worth mentioning is that the fortunate few will come from Europe only, as Mercedes-Benz and AMG will put up only 200 SLS AMG Electric Drive sports cars for sale, so that each sold vehicle could be left under the company’s supervision. Deliveries to other countries are not expected so far.
SUMMARY
The Mercedes-Benz SLS AMG Electric Drive is a rather anomalous phenomenon among electric sports cars — it’s too radical for an everyday car and its battery capacity is insufficient for a race car.
According to the journalists, this vehicle was used by the carmaker to test the powertrain with four independent electric motors. If those 200 “test” customers give high rating for this supercar, most probably the world would see new similar models. By the way, the first reviews given by European and American journalists are very positive.
