So it is time to see what happens when you drive a Mini E well past zero.
In a previous post I noted that it can take awhile to actually get the gauge to stay at zero. When it first reaches zero, it tends to bounce back up as high as +3% when regenerative braking is used or just when standing at a stop light.
Tonight I purposely kept driving past the point at which the gauge stays at zero. With the heater running. Just driving around the block by my house.
I got almost another ten miles as the maximum power slowly declined. There is not a road speed limit per se as the charge drops below zero, but a torque limit that gets greater. So you can still go fairly fast on level road or downhill, but I got to the point where a moderate hill limited me to 15 mph.
The real issue is that it doesn't want to start charging when it has been driven well below zero. I finally pulled out the 120 volt portable charger, and it would accept charge from that. After a few minutes charging at 120 volts, the car would accept 240 volts at 12 amps. Then I bumped it up to 32 amps. No problem. A few minutes more and I bumped up to 50 amps. OK. But it was almost ten minutes before the gauge went above 0%.
Also, the charge gauge needle never drops below zero while driving. That range between Zero and Off is not a "negative zone". It just makes it clear when the car is on or off. The digital gauge never shows negative either.
So I am not worried about shorter range in the approaching winter. I can make do with the 120 volt charger at work. My 120 mile commute has usually left me with 20 miles of range when I get home after also charging at work with the little box. And I can get over 30 miles left when I arrive home if I am careful. So as the heater gets used and colder weather reduces the range a bit, I'll be fine. Now I know there is another ten miles in there if something goes wrong. I hope I never have to use it again though.