Took my car to the dealer today to have battery checked out. They did a "load" check as well as a "battery drain" check and they said everything looks OK. So, still don't know what drained the battery. The service dept. then told me that newer vehicles cannot be stored for very long periods (over a week or so) because the computers drain the battery and that if I don't use the car for over a week I have to remove the memory fuse to disengage the battery. He also told me that each time I do this everything has to be reset, ie radio, clock, etc. - which is a nuisance.