| First Drive | Valencia, Spain | Mercedes-Benz SLS AMG E-Cell |

We're no strangers to electric vehicles here at Car Enthusiast, but supercars that run off the mains are still something of a commodity. Cue Merc's SLS AMG E-Cell, which has almost as much power as the petrol-engined SLS, but none of the tailpipe emissions.

In the Metal

You'd be hard pushed to tell the difference between the petrol and the electric SLS without looking for the E-Cell badges. It's still very much the modern supercar, with its wide and flat, ground-hugging stance, imposing road presence and the all-important gullwing doors. The yellow/lime paintwork won't be everyone's idea of taste, but we reckon it's rather fitting for a futuristic supercar.

Duck beneath the gaping open doors and you're met with the kind of exuberance that's to be expected from such a special Mercedes. Leather bucket seats with matching hide on the inside of the doors and the dash, a huge transmission tunnel topped with carbon fibre and a thick Alcantara-rimmed steering wheel all feature. It's all very AMG.

As for the drivetrain, it consists of three lithium-ion battery packs - one in the boot, one in the transmission tunnel and one at the back of the engine bay. Four electric motors send power to each wheel but, unlike many forthcoming electric cars, they're not mounted directly behind the wheels. The motors are houses in two 'gearboxes' - one at either end of the car between the axles - so the wheels are independent from the motors. That all adds up to roughly a 330kg weight premium over the petrol-fuelled SLS.

What you get for your Money

The SLS E-Cell is polished enough to be ready for production and its engineers are more than keen to see it in showrooms. They reckon that further battery tests are required before it gets the green light, though.

As for how much the SLS E-Cell would cost - that's anyone's guess. The expense of developing such an advanced electric performance car can only add to the petrol car's already fairly lofty list price. According to the enthusiastic types at AMG, if the SLS E-Cell does make production then there will be "more than 20" examples built.

Driving it

By now you may well have heard that electric vehicles deliver all their torque in one gigantic slug from the off, so it will come as no surprise to learn that the SLS E-Cell does exactly that. Straight line performance isn't the whole story though, as the car has a number of settings to adapt its driving style and also mimic the characteristics of an internal combustion engine.

The 'Park', 'Reverse' and 'Drive' buttons on the centre console do what you'd expect them to, but curiously, the gear-shift paddles from the petrol car are still tucked behind the steering wheel. As there are no cogs to speak of, the paddles actually adjust the car's programming to either increase or reduce the effects of 'engine braking' when the driver lifts off the throttle. There are four green bars on the screen between the dials that indicate how ferocious or non-existent you like your lift-off action and, after trying both extremes, we can confirm that it's incredibly realistic.

Drivers can toggle between Comfort, Sport and Sport Plus via a small dial at the front of the centre console. Again, this doesn't seem like anything new, but it's not just a case of making the suspension soggy or rock hard. The sportier settings free up a considerable amount of extra power and torque throwing 'range anxiety' to the wind.

We first tried the SLS in Comfort mode and, though hardly slow, it wasn't supercar quick. Our second run was in Sport mode, which opens the floodgates - a massive 649lb.ft of torque and 526bhp becomes available. The back of the car hunkers down and squirms a little under heavy acceleration but the fine chassis puts the power down well and the immediacy of the torque makes the SLS a brilliant point-to-point car. The 6.3-litre V8 petrol equivalent develops 563bhp and makes the car 0.2 seconds quicker to 62mph (the SLS E-Cell takes 4.0 seconds), but that's splitting hairs in the real world.

Our time in the prototype car was short and the smooth surface of the closed test track made it tricky to assess the ride and handling thoroughly. Even so, the steering is laser sharp and the SLS remained confidently flat during fast cornering.

Worth Noting

It might be slightly down on power compared to the petrol SLS, but the E-Cell actually has a lower centre of gravity due to its packaging. The weight bias is one percent more towards the rear for the same reason, but it's such a small amount that the effect on the handling is unnoticeable.

Summary

This is a sign of things to come for performance cars. The range issues that go hand-in-hand with electric vehicles are still prevalent but that isn't likely to disappear until batteries catch up, so it's just a waiting game for now. Equally, the development costs are still astronomical, so those with the means to buy a supercar should be prepared to pay a serious premium for a something like the SLS E-Cell.

We really hope that Merc gives E-Cell the all clear for production. Eco-friendly supercars are starting to rear their heads but with the exception of the Tesla Roadster, the SLS seems to move the game along more than most. It deserves to be sold to the public, however few examples Merc builds.