IMO, this is a huge problem for the future of electric cars. If you own one, you will always have to worry about this when going away for extended periods. When I had my honda insight, just leaving it un-driven for 2 weeks would seriously deplete the battery. I never killed the battery, but after the car had 130k miles, just leaving it garaged for a few days would noticeably deplete the charge. I'm afraid that electric cars will become the new disposable car at some point because no one wants to flip the bill for a new battery pack.