Mitsubishi Repair: 1997 Galant ES Auto Re:Charging system failure, auto transmision, failure point

Question
Recently,I was given a 97 galant es with a 2.4 and auto transmision a friend had stored for about 18 months.I replaced the dead battery with a brand new one.I drove about 500 miles without incident.We suddenly were hit with some snow and I had to use the blower and lights and the radio started to fail,and slowly the lights and wipers became sluggish.I shut them off and limped home till the weather broke (2 days)and returned to a dead battery.Charged it and decided to replace alternator to be safe.Same trouble..weak electric..dead battery.Returned battery (tested bad in store load test)for new,good tested battery.Same problem..Replaced alternator again..tested with voltage meter to be working (about 14 or so volts).Seemed fine with lights and blower in test drive of about 40 miles...then dash seemed dim when parking.Next morning I popped the hood and Tested voltage to be at the failure point again (12-13 volts without accessories on)on meter.I am at wits end.Can you please suggest some helpful advice?

Answer
Vinny,
This sounds like a bad connection in the charging system.  With your system in the state it's in (12-13 volts at the across the battery with the engine running at about 2000 rpms), you need to trace back to find where the voltage drop is.  Check between the 'bat' terminal and ground at the alternator.  Check the battery cabling to the starter.  Are there any 'idiot lights' illuminating on the dashboard when the engine is struggling?  You need to find where the voltage in the charging system starts displaying a constant 14.6 volts.  Poor grounds, frayed wires, short circuits, corroded connectors can all cause these sorts of problems.  

If you pull your alternator, you can bring it to a place like AutoZone and they can load test it for you to be sure the replacement is fully functioning and putting out the voltage and proper current.  Sometimes if a connection is bad, it can quickly kill an alternator. Even fluids dripping on an alternator can do it.
Good luck!