When I first got my 2016 Volt several months ago, the EV range when fully charged showed 48EV. Over the next month, each time I charge the EV range increased until it was amost 70 EV. The car sat idle for a few months (due to ilness) and now I am driving again, however, the EV at fully charged is usually between 45 and 48. I know that in cold weather more electricity is used but I seem to be using it extremely fast. In only a 4 mile round trim I will use about 6 to 8 EV. Is this normal operation or is there something that needs to be fixed.