I picked up an ELR a couple of weeks ago, have driven it daily with no issues and love the car. We're taking our first road trip in a week, about 400 miles one way. Anything I need to do before hand or anything unusual to look for. I plan to leave with the battery charged and keep it in hold mode to keep the battery for city use when we arrive. Does the engine run harder in hold mode then it normally would after the battery is depleted?