I drove my 2011 535 for 14 months, 17,000 miles and had zero battery issues. Almost every week the car would stay parked for 2 or 3 days while traveling and never was a problem. And mine was an early July 2010 build. I think this battery issue may be an isolated case and not an expected behavior.
2012 535i | Built 8/25˜9/07 2011 | Delivered 10-15-2011 | Carbon Black | Oyster Black Dakota Leather | M-Sport Pkg | Luxury Seating Pkg | Premium Pkg | Premium Sound Pkg | Technology Pkg | Sport Auto Trans. | Split Fold-Down Seats | Heated Seats | Side & Top View Cameras | Heads-Up Display | BMW Apps | Black Panel Display | Trunk Lip Spoiler | Roof Spoiler | Quad Exhaust | AirBlue Tint | Turner Wheel Spacers | Euro Plates | Hardwire V1 w/BOB | Media Cradle | Debadged | Kitchen Sink Pkg...