Since this autumn, I don't know for shore if the weather is the reason but my Ampera ICE start to kick in on 9.4khw used or even lower, but in the summer I get 10.2, even 10.5 once. I try to fully discharge and fully charge over night for last week in hope to reset maybe the computer but no effect. My range is very good, like 70km on 9.4kwh but is this a sign of battery degradation or just the weather. Since this year I never look at the KWH, only range but a friend told me that I should look on the Kwh if I want to see if there is a degradation of the battery.
How is your Volt/Ampera kwh used on low temp, like 5-10 celsius. In the winter my range drops from 70km to 35km.
PS. I drive mostly short trips with many stops and go. I understand that also affect. If a have 3 km range left and shut down the car, when I start again ICE kicks in. Using preheat I don't get any significant change. If I drive 16km with one stop of 5 min, I use 3kwh and same distance no stop - 2.5kwh (in the morning / 9-10 celsius).