Comment by londons_explore

And the range extender was underpowered. Drive up a hill on a freeway at 70 mph and the battery would deplete and the car would slow down to 25 mph which was the fastest the range extender could make it go up a gentle incline.

It's dangerous to do 25 mph on a freeway... There are some roads I'm too scared to drive my i3 on now.

If you pulled over to let it recharge, it wouldn't do so, since the range extender refuses to run at full throttle when the car isn't moving fast (perhaps no cooling fan??)