BMW's i3 and i8 concepts - two practical, exciting electric cars

BMW has fully committed itself to the battery-electric driving revolution by setting up a whole new sub-brand - BMW i - devoted to emission-free motoring. Now, the i group has released details of two concept cars that look set to become production models within a few years. The i3 concept is a fully-electric city car with an everyday driving range of around 160 km (100 miles) per charge, and the i8 is a sporty 4-seater plug-in hybrid that combines electric and petrol drive to give a good compromise between emission-free commuting and petrol-powered range and performance. Both cars make widespread use of carbon fiber-reinforced plastic (CFRP) to keep weight down, and both offer a raft of fascinating new driver assist and efficiency initiatives that seem likely to make it through to the real world.

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A pair of new electric Beemers look reasonably close to production, each with a decidedly different focus and a sensible, utilitarian view of electric motoring. Both have been designed from the ground up to maximize the advantages of battery-powered driving, unlike other BMW efforts like the MINI E and ActiveE.

The BMW i3 - all-electric city slicker

First up is the town car getabout - the i3. As a fully electric car, it's mainly aimed at urban commuting, but its battery range is specified to a level a little beyond that. On the FTP72 cycle, it's rated for 225 km (140 miles), but BMW says the car's everyday range, being driven by regular lead-foot clowns like you and I, is more like 160 km (100 miles.) That's heaps for your general commuting duties.



Acceleration is in the range of 8 seconds to 100 kph (62 mph), but it should be fairly zippy off the line, as it develops 100 percent of its torque from a standstill. Top speed should be around 150 kph (93 mph) - but that's electronically limited, because autobahn speeds can be brutally draining on most electric vehicles.

The i3's large battery pack sits under the floor of the vehicle in a slab that's protected from crash damage by a number of buffer zones in the structure. As batteries are typically the most expensive part of an electric vehicle, you'd certainly want to protect them.

The 170 hp electric motor, single-gear drive system and differential are located over the driven rear axle, and there's room there for an optional range extender - a high efficiency petrol engine that putts away and generates electricity to charge the batteries. With the range extender on board, you can roughly double the i3's range, and fill up at any petrol station.