New owner battery question

[virgopelo]

Hi to all ,new BMW X5 2011 35D need advice with the battery ,I purchase this car from the auction and has 103 000 miles I have no clue on the history of the car I know that I have to do some works but I an fine with that this car has not warranty,this is going to be my weekend machine .
It has some message on the main screen (chassis stabilization malfunction and dsc xdrive malfunction. No other code show on the dash and the engine sound very very nice
I need to start with the battery ,this car came with the 90a white battery and it need to be replaced
I try to charge this battery with a 2 amps charger and after 48 hours the auto charger was unable to fully charge so I puti back on the car to see if it start but no ,no cranking enough to start the car .
Has any one use a optima red top battery on this car ?
Thanks in advance