...I’d just come through a heavy but localised rain storm on the M20 when the i3 started to slow. It was a gradual process, from motorway cruising speed all the way down to 44mph. By this time I was travelling up a slight incline and had effectively become a slow-moving obstacle. Lorries were catching me with quite frankly terrifying closing speeds. It was three or four minutes - which was long enough to make me consider pulling over - before the i3 recovered; just as slowly as it had lost speed, so it crept up.
“It’s not a limp-home mode as such,” a BMW spokesman later told me, “but once the charge runs down to five or six per cent and the range extender cuts in, if you keep driving at 75-80mph it can’t maintain the charge.” Rather than damage the battery by running it completely flat, the i3 had restricted our performance.
What I should have done, it transpired, was engange the range extender when there was still 30-40 per cent charge in the battery. Still, the car had covered my mistake, albeit in a slightly alarming fashion, and the remainder of our journey back into London went without a hitch (save needing to add another 7.5 litres of petrol).
Putting aside the loss of power, the i3 was a delight to drive...