Chevrolet: 94 Cavalier Charging System, freway, charging system

Question
The car died on the freway with all the electrics cutting out. I changed the altenator jump started the car and all was fine.For days later the battery died. swapped it for another it started first time and of we go. Four hours later arrive home and notice the powere windows are struggling to close. Switch off the motor and tried to restart and nothing. Am I missing something obvious or is there a serious problem?

Answer
Mick ;
Hi - I would check the charging system with a meter to see what the alt. is putting out , and the battery also. it soulds as if something is shorting out or not charging enough. it could be a wire grounding out or the charging system could be bad.  ok