Electric vehicle range—whether in a full EV or a PHEV—as with the remaining range or 'miles to empty' display on a petrol vehicle, is a calculation based on the available charge in the battery but also recent energy consumption. On an electric vehicle, battery efficiency is typically impacted by colder temperatures, but also energy consumption increases in the winter months due to increased use of cabin heating and battery thermal management, so we would expect both EVs and PHEVs to indicate less available range at this time of year.

Given the age of the vehicle we would still expect the battery capacity to be 100% or very close to it, so the reduced available range indicated is a result of the conditions. When manufacturers advertise the available range of their vehicles it is always prefaced with 'up to XXX miles' to reflect the fact that available range is variable and impacted by battery health, ambient conditions and driving style and cannot be guaranteed under all circumstances.