You guys are freaking me out... If something is intentionally done to reduce the charging current while the vehicle is operated to save gas, and a $100 battery needs to be replaced every year, I am officially and seriously outraged and will forever change my opinion about BMW. Fake and non-existant "savings", which in reality switch profits from the oil industry to car battery makers and/or other parts makers (start-stop function and all the elements that destroys prematurely, incl. the battery...) and BMW service centers at the same time. All of that to show a better number on the MPG fact-sheet, but in practice fooling us all and robbing of money in bright daylight.
I sure hope this is just a glitch that some F10s are experiencing, although, even that sounds scary I must admit. Seems like a no-win situation.