450 er not holding charge..need help

I have a 450 er that wont hold a charge, iv bought 3 batteries this summer hoping maybe they were junk. I finally decided it was probably my stator, hooked up a volt meter and it read in the 14’s while running so I figure its not the stator, and in the mid 12’s when not running, I also disconnected the ground from the battery and help my meter to my frame for maybe I had a short some where but had no luck. don’t know were to go from here and need help fast. heading to Waynoka in TWO WEEKS