Just wanted to add my complaint about this same issue.

Battery dies in less than 70hrs if the car sits in my heated garage without being driven in that time-span. I'm having it checked by my Subaru dealer now.

Had battery issues from the beginning. At one point the dealer kept the car for 3 weeks to work on the electrical system, and I still had issues. I had to have the battery replaced twice, which was a large expense. My husband, WALTER NOLLEY, passed away May of 2020. I have had to deal with this battery issue on my own. Each time I had to take it in for battery issues, it has cost me money, time and inconvenience. No one can identify what is causing the problem.