28km one way, 60km round trip, Do i need conserve?
the heater is 5 kw, car has 170km range over 33 kwh battery, so each kwh can drive 5km.
Each hour on heater is 5kwh, will lose 25km, so say two hour round trip in worst weatherm will eat 50km off the range.
I still be able to get a round trip...