Water damage Q ?

Okay On Friday i semi submerged the xj, wel water was comming in from the bottom of the doors, It was fun but when all said & done after I cleaned everything I am having low voltage problems. I will first start the vehicle & have 12v but 5-10 min later the voltage will drop & warning lights show up. what is my problem? bad ground , bad sending line ? damaged alt ? What do I check first to eliminate this problem. The battery seems to be holding a charge still . Any suggestions :eyes:

Never mind , I just took apart the alt & cleaned it up & put some new brushes in it good to go. :wave1: