I hit the warning reserve on Saturday evening for the first time. came on at 12% / 9mi remaining about a mile from my house.
Pushed the limits this time. Did a full extended range charge, drove to airport with wife, 2 kids, and 4 suitcases packed in. Parked at off site valet lot showing 69mi and 70% remaining after a 38 mile drive. Well in the comfort zone for the 38 mile return trip. Average showed something near 3mi/KwH, maybe 2.9 in what was perfect weather. Parked for a week with no concerns.
What I didn't count on was the 45 degree, dark, rainy drive home with again a full load of people and luggage. That required heat, defroster use, wipers, headlights, just about every accessory load for over a hour. It dragged the economy to 2.0 mi/KwH and we had only a few miles to spare pulling into the garage for a long recharge.