The fuel cell stack can now also operate at 25deg C below freezing and it will start up instantly at -15deg. Cold-weather operation proved a developmental hurdle.
The hydrogen is pumped into the car’s three carbonfibre-wound tanks at 700bar and each tank holds just under 4kg of fuel. Mercedes claims a range of 250 miles at a cost today of £32. The ability to mount these tanks under the floor of the B-Class is a boon for crash safety.
While the fuel cell generates a charge to drive the electric motor, there’s also a 35kWh lithium ion battery mounted under the boot floor. This is used to both store energy from brake regeneration and for ‘cold starts’ while the fuel cell is coming up to its operating temperature. The battery can also be used to power the car on short journeys and when manoeuvring at low speeds.
What's it like?
It’s nearly impossible to tell that the car is anything other than a stock model. The interior is unchanged, there’s no loss of boot space and the only exterior clue is the special refuelling interface hidden behind the filler flap.
In terms of ride and handling, the B-Class F-Cell feels remarkably like its conventional sister cars. That is, a little dated. It suffers from a pretty stiff-legged ride, crashing over poor surfaces rather too often and delivering quite a lot of noise to the cabin while doing it.
However, the electric motor offers pretty brisk progress and, on good roads, the lack of underfloor mechanical action is very noticeable by its absence.
The combination of torque and a single transmission ratio means acceleration is utterly seamless. At higher speeds the car delivers a rather odd sensation, a kind of very low-friction progress, which might be best described as ‘whizzing’. The brakes, however, need to be stronger and more progressive.
Should I buy one?
There’s no doubt that fuel-cell motoring is impressive. The performance is uniquely delivered and the environmental impact minimal.
But there are two huge hurdles in the way of fuel-cell cars before we all rush out and buy one: the cost of the technology and the lack of a hydrogen refuelling infrastructure. But while Germany looks like it will install a serious network between its big cities by the end of the new decade, British drivers are unlikely to be so lucky.