Double Dark Side! Diesel & 8P
Alternator could be on its way out. Mine started off with the battery light (which means the batteries charge is low) then 1 day the car wouldn't start. I jumped it and got it home but on the way home the ESP light came on and the general performance of the car was shocking. I had misfires too and when I scanned the car with VCDS there was cam timing errors and all sorts! All issues went when I fitted a brand new alternator.
If you do a search for my thread (will have alternator in the title) there's a YouTube video in there that shows you how to check the alternator is healthy.