Electric Porsche Boxster EMay 30, 2011
One of the most exciting current electric prototype cars has to be the Porsche Boxster E, and Green Car Guide was able to experience the car at the Michelin Challenge Bibendum in Berlin.
Porsche had two versions of the Boxster E available, a rear-wheel drive and a four-wheel drive model. Both cars look and feel almost identical to the normal Boxster, but with zero tailpipe emissions
The ‘mid-engined’ four-wheel drive car can accelerate from 0-62 mph in 5.5 seconds, go on to a limited top speed of 124 mph, with a range of 107 miles.
With the two electric motors developing a total power output of 180 kW and a maximum total torque of 540 Nm, a
cceleration in the car feels rapid, as it does with most electric performance cars, thanks to 100% torque available from standstill. This is an interesting contrast with combustion-engined Porsches, which need to be revved to high levels to get the most from the performance of the engine.
The two electric motors can also recover energy that would otherwise be lost when braking. Rates of recuperation can be adjusted by buttons on the steering wheel.
Sitting in the car, it feels reassuringly like a regular Boxster, with a familiar interior except for a few of the instruments. The orange elements on the body and in the interior are intended to denote electric power.
Overall the Boxster E feels very similar in terms of quality to a production Boxster, including in the suspension department, which felt rattle-free, unlike the Tesla Roadster in which we travelled to the event through Berlin, which emitted various clunks and thumps over uneven road surfaces.
In terms of weight, the Boxster E tips the scales at 1,600 kg, compared to 1355 kg for the Boxster 3.4 S. This has an impact on the handling of the car, but Porsche has done everything it can to keep the best weight distribution, despite all the new electric technology. The company also stresses that having the electric components in the centre of the car, thanks to the Boxster’s mid-engined layout, is safer in the event of a crash.
The four-wheel drive version features
two independent electric motors. The rear drive unit, comprised of motor and transmission, together with the power electronics for controlling the electric motor, is located where the manual transmission and exhaust system are accommodated in the conventional Boxster.
The second drive unit sits at the front, where the fuel tank used to be. The luggage compartment houses the power electronics unit for the front axle electric motor. A central electric control unit looks after the synchronisation of the two electric motors and controls the drive torque distribution to the front and rear axle.
The rear-wheel drive version has no
front electric motor. This car delivers a reduced power output of 90 kW and torque of 270 Nm, resulting in 0-62 mph in 9.8 seconds, with a top speed of 93 mph.
The 341 kg lithium-iron-phosphate based traction battery is manufactured by Porsche and has 440 individual cells. As with the combustion engine in the production car, the traction battery is installed in the Boxster E from below and can be taken out and replaced very quickly if required. The battery takes around nine hours for a full charge, but this time can be reduced using a rapid charging function.
One of the demonstration cars was virtually silent, as most electric vehicles are, but the other Boxster E generated ‘artificial’ noise, thanks to the Porsche Active Sound Design system,
which made it sound like a combustion-engined-powered Porsche – which was very confusing for many onlookers, as they had no idea that this was a zero-emission electric car. Electric cars are likely to have to generate sound very soon to conform with legal requirements, to help ensure the safety of pedestrians with impaired vision.
Although the 0-62 mph time of both the petrol and the electric versions of the Boxster are similar, at 5.3 and 5.5 seconds respectively, it’s the top speed where you’ll notice the difference; while the 3.4 S can hit 170 mph, the electric prototype can only manage (a limited) 124 mph. However this is still 54 mph more than the UK maximum speed limit.
As with all electric cars, it’s the range that has the greatest limitations. The Boxster E can only cover 107 miles on one charge – and you can pretty much guarantee that most people would drive it in a way that wouldn’t achieve this distance.
The one unknown is the price – the Boxster 3.4 S costs £43,800, and although Porsche is not giving any idea about an estimated price for the Boxster E, if it did get produced, you can guarantee it would be a lot more than this – even with a range of just around 100 miles.
The Boxster E prototypes are being used as part of the ‘Model Region Electro-Mobility Stuttgart’ large-scale trial in Germany to explore the everyday practicality of all-electric vehicles and how they are used, especially in terms of driving and battery charging.
Officially, Porsche says there are no plans to put this car into production, but even if there is no electric Boxster, it’s likely to be a testbed for some other future Porsche EV. We look forward to seeing an electric production Porsche as soon as possible.