Tonight it was in the low 30s. Before an hour long drive, the car was fully charged and plugged in, and I preconditioned it for about 15 minutes. Shortly after taking off, I got the notice that the engine was on due to temperature. The engine cycled on and off the entire trip, even when the climate control system was turned off. I thought this function was to heat the cabin. Is it also to keep the engine and battery warm? And what's the benefit of setting the "engine on" temp to the lower setting? Do you otherwise never get to enjoy pure EV driving in the winter?
As for keeping me warm, in Eco mode there simply is no "ramp up" to the set point temperature. It blows on low, with minimal heat, and I don't think it cares if you never reach the set point. In Max mode it works like any other car you may be used to.