BMW battery bike for the real world
The key word in individual mobility these days, particularly in big cities, is sustainability. Like it or not, growing traffic volume, rising energy costs and increasingly draconian CO2 restrictions on vehicles in inner cities will define how we get around in the future.
BMW's response to these challenges has, until now, been a little spotty, including the weird-but-wonderful mid-1990s C1 scooter-with-a-roof, which continued to outsell every other scooter on the SA market even after BMW SA tried to kill it and, more recently, the C600 Sport and C650 GT maxi-scooters.
But, along with everybody else, BMW is now subscribing to the party line that the answer in the medium term is solve the energy-density problems inherent in storing electricity - that is, to build battery-powered vehicles with acceptable performance and range.
Never mind where the electricity comes from or how much damage is done to the planet in generating it…
So here we have the C Evolution scooter, a near-production battery bike that BMW says will reach the market (albeit at a premium price - they make no bones about that!) in the foreseeable future. They've actually built five of them, which are being used as demo vehicles to get BMW customers - and anybody else whose ear they can bend - used to the idea of practical battery-powered scooters, in a real-world situation.
To start with, it doesn't have your typical 2kW vacuum-cleaner engine. The C Evolution's 60-volt prime mover is rated for 11kW continuous output and 35kW peak power, albeit in very short bursts. It's mounted on the swing-arm pivot to minimise unsprung weight and drives the rear wheel vial a toothed belt and planetary gear
LIMITED TOP SPEED
According to BMW top speed is limited to 120km/h in the interests of battery range, it'll pull an effortless hill-start two up and, at least as far as 60km/h, it'll keep up with a 600cc maxi-scooter.
The 150-volt, 8kWh battery pack is made up of the same type of lithium-ion cells as used in the i3 battery car (although nowhere near as many) and BMW claims an operating range of “up to 100km”, although we suspect that was measured at a steady 45km/h on a perfectly flat test track.
The motor is also used as a generator to recover energy under braking. As soon as the throttle is closed, the bike will slow down just like a conventional bike under compression.
When you start braking, the effect will increase - in conjunction with conventional braking - to scrub off speed in way that feels 'right' to people used to conventional biking, and extend the range by 10-20 percent depending on how hard you ride.
It also generates a lot of heat.
that’s why, although the battery pack is air-cooled, the motor and control module have their own liquid-cooling system.
The battery is charged from a standard 220V domestic plug, or a charging station on the street, and a full charge should take less than three hours. There's a standard car-type charging socket on the left side of the footwell and a cable in a compartment on he right - BMW says it's the only battery scooter on the road that can be charged using the same infrastructure as an electric car.
The battery box is also the frame; the swing-arm pivot bolted on at the rear, while tubular-steel front and rear sub-frames are bolted to the top, keeping the weight central and as low as possible.
The C Evolution runs 15” alloy wheels at both ends with special lightweight Metzeler tyres (120 in front, 160/60 at the rear) on 40mm forks and a single rear damper. Braking is entrusted to three 270mm Brembo discs with floating callipers and ABS, with a special sub-routine that locks the rear brake when the side-stand is extended.
The instrument cluster is based on that of the i3, with a large, easily legible speedometer display, a battery charge meter, an 'energy balance' display showing whether you are using or recuperating energy, and warning icons for electrical calamities such as current overload or short circuits.