I have a 1983 Ford F150 and its draining every battery i put on it, ill put the fully charged battery on in the morning and after a day or two its complety drained. Anyone know what may be causing this? Thank you

 

My Dad had a F150 with the same issue. After tracing just about every wire there was a way to trace, it turned out to be a shorted alternator. After replacing it, all was good. If you have not done that, consider it.

 

A simple way to be sure would be to remove the battery lead from the alternator when the vehicle is not in use and see if the battery still goes dead. You might have to remove the ground cable from the battery in order to safely disconnect the alt lead, protect it from touching any other parts with the terminal end . Reconnect the ground cable and see what happens. you shouldn't try to run the vehicle with the alt lead disconnected unless you remove all the alt wires.