I am late to the party here.
I am late to the party here. I have a 2016 outback. I am on my second battery. it was having problems starting the other day. I took it to the dealer and they said that everything checked out. I did some analysis and discovered that there is a flaw in their charging algorithm. Typically, alternators output voltage is around 14 volts. The Outback only supplies about 12-13 volts under most circumstances. If you engage any additional peripherial functions like headlights, the voltage will increase to 14 volts. Subaru knows about this but not sure that they can fix it. Since the output voltage is only 12-13 volts, the battery deteriorates with time. I have found that driving with my parking lights on, increases the voltage to 14 and keeps the battery charged. A battery tender is another option. Remember that every time you start the car, lowers the battery starting capacity. This is also compounded by phantom currents. I contend that if the alternator put out 14 volts all of the time, we would not have these problems. I did confirm some of this with the service tech.