What is it?
BMW i brand’s first model, the keenly anticipated electric powered BMW i3. First previewed in concept car form back in 2011, the four-seat hatchback i3 has now progressed to pre-production stage, with UK sales set to begin before the end of the year.
The pre-production i3 differs little from the most recent concept, which took the form of a two-door coupé seen at last year's Los Angeles motor show. The car boasts proportions not unlike those of the Mercedes-Benz B-class, but with a much more contemporary appearance and more modern detailing, while the lack of B-pillars has allowed the use of coach doors at the rear to provide excellent access.
The i3 is the first road-going BMW to be based around a carbonfibre body structure. BMW says the extensive use of the material in the i3 has helped achieve an impressively low (by electric car standards) 1195kg kerb weight. Special crash paths, including patented honeycomb structures within the side sills, are also claimed to provide the i3 with class-leading levels of crash protection.
Power comes from an electric motor mounted low down within the rear axle – a position that has allowed BMW to devote the entire space under the bonnet to improve crash worthiness. The synchronous unit weighs 130kg and produces 168bhp, giving the i3 a power-to-weight ratio of 141bhp per tonne – just 10bhp per tonne shy of the Mini Cooper S. But it is the torque that really counts. With 184lb ft, the i3 boasts 5lb ft more than the Cooper S, and it arrives 1600rpm earlier, from the very first touch of the throttle. It is sent to the rear wheels via a single-ratio gearbox that offers the choice of three driving modes: Comfort, Eco Pro and Eco Pro+.
This all helps the i3 dash from 0-37mph in 3.8sec and 0-62mph in 7.2sec. Top speed is limited to 93mph, at which the engine is pulling a maximum 11,400rpm, to protect the state of battery charge and subsequently its range.
The new i3 offers a range of up to 118 miles on the European test cycle, although BMW’s own projections are less optimistic at 81 miles in wintery conditions and 100 miles in the summer. Still, they are well within the 30-mile average daily commute the German car maker identified in UK customer trials of the Mini E. As it is, BMW describes the i3’s range as being “adequate to meet the day-to-day mobility needs of the target customers”.
BMW will also offer the i3 with a range-extender (REX) option. It will use a modified version of the 650cc two-cylinder petrol engine used in the company’s CT650 GT maxi-scooter, with a 9.0-litre fuel tank sited low down and ahead of the front seats. The combustion engine acts purely as a generator to provide electricity to the battery, and so configured the i3 is claimed to provide a range of up to 186 miles.
The 22kWh lithium ion battery used to power the i3’s electric motor comes with a warranty that is valid for up to six years or 100,000 miles. Claimed to weigh 230kg, it consists of 96 individual cells mounted low down across the entire length and width of the car’s flat floor. BMW says the battery, which is kept at an optimum 20deg C by its own air conditioning unit, has been designed to allow the replacement of damaged cells.
Recharging times vary, but BMW offers a wall box charger that is claimed to provide a full charge within six hours, or the battery can be charged from 20 per cent to 80 per cent capacity within 30 minutes when plugged into a contemporary 40kW fast-charge station.
Underneath, the i3 uses a bespoke chassis that boasts a 50 per cent front/50 per cent rear weight distribution. The front end is supported by MacPherson struts while the rear uses a five-link arrangement that mounts to the electric motor’s bell housing. Standard 19-inch forged aluminium wheels wear relatively narrow 155/70 tyres, to save weight and reduce both air and rolling resistance.