I did something really stupid - when I came home earlier I noticed that for some reason my parking lights were on, so I turned the knob and shut them off - only I turned the knob the wrong way and, in fact, turned ON my headlights. About forty minutes later someone knocked on my door and told me the lights were on. I knew I was in trouble when my electronic lock opener wouldn't open the car - sure enough, forty minutes later, dead battery. Happily, the Auto Club was here in ten minutes, charged it, I took a twenty minute drive and all seems to be well. They now have these nifty portable battery jumpers - I think it's just one cable and I may go purchase one and keep it in the trunk.