I fully charged ready for a trip today. Took the car to run a few errands, about 15 miles, now showing 294 miles left. Plugged in to recover those precious miles before leaving on the trip and it will not charge, says "Charging Complete", but I know there are 15-20 miles more that could be charged, why is it not charging? (Charging limit is at 100%, and it did charge to that limit before I did my errands)