Alternator not charging

[Johnno1951]

OK,this was wrong from the first day of registration, smart alternator not switching up. Result one flat battery, Subaru recommended driving around with the side lights on. To keep the battery charged. I have replaced the alternator, as it wasn't switching up. Only when it felt like it, Now today the alarm went off, yes the battery was flat AGAIN. Had a new battery fitted only 2 years ago, so it looks like it's not being charged.Take it out every day, so any ideas folks on dodgie alternators.