help please 2010 bmw 335i xdrive N54 E92 im at a loss

[2010e92-n54]

i own a the bmw for over a year now, yesterday after washing the car i lost/drained the battery sitting in the carwash bay long enough to wash her 10-15 min tops.
didnt wash the engine bay. my queston is this what may cause the battery to get drained or where to begin to start looking at any help will be appreciated.
ive replaced the alternator and battery recently as well her in a bit ill run the scan tool and see what it pulls up

 

[Solo Man]

Since you had the car washed I would check for water leaking into the car. Check the carpets for water. if they seem damp at all i would remove them and check all the electrical connections underneath.

 

[2010e92-n54]

Since you had the car washed I would check for water leaking into the car. Check the carpets for water. if they seem damp at all i would remove them and check all the electrical connections underneath.

Me and my partner did that including the ecu box under the hood on passenger side. Bone dry. We hooked up jumper cables and It started first crank.. idk im are a loss