Before you spring for a new alternator, check the brush assy in yours. If you have no additional hi current loads, the stock unit should be OK. I'll bet those brushes are shot. Easy, inexpensive replacement. Remove connector, two phillips screws, tip the old one out and take a look. If you've got less than about 5/16ths left, that's the problem. worth a look..
2000 Dodge Grand Caravan SE
No matter what you fix, there will always be something else to fix..