charging issues

[adamkat22]

i have an 82 300TD. Had a few times in the last month or so that I needed a jumpstart. The first time I put a new battery in. Was a while before it happened again. I guess its possible that you can go quite a while on a battery without the altnernator charging it (i.e. a full battery with one of these gets you quite a few times through the glow cycle and many miles of headlights before draining it completely?). After the second time the battery went dead I put in a new VR (well by "new" i mean I pulled one off my parts car...that was newer than the one on there). A few weeks later the battery went dead again. I got jumped. The jumper cables were only on for about 30 seconds and the car made it all the way home with the lights bright and the windshield wipers at full speed...which made me feel like it must be getting a charge from the alternator.

My understanding was that the alternators rarely go bad on these cars...that it was mostly the VR. what should I be checking to see where my problem lies? Thanks