Driving it is EXACTLY what…
Driving it is EXACTLY what is killing the Battery ! They have Software in the Vehicle that thwarts charging the Battery UNTIL the Vehicle passes a series of "tests" .... and the bottom line is the Battery will not get recharged for up to 30-miles OR up to 30-Minutes !!! Meanwhile the battery is slowly being damaged.
SO ... if you try to "Re-Charge The Battery By Driving...." you are going to have to WASTE A LOT OF GASOLINE and TIME; of course Subaru did NOT tell the US EPA about this well hidden Charge-Program in their Vehicle's (hidden) Software !!!!