3.6 Pentastar Rattling

Hi. I drive a 72 Swinger, but I have a question about my other car -- 2014 Town & Country 3.6 with 115k on it.

Six months ago, the battery light came on and the battery went dead. It was the original battery (!) and the alternator was bad, so I got a new battery and swapped the alt with a rebuild from NAPA. Three months later, the alternator was making a whirring/whizzing noise -- no batt light and it was charging. I pulled it and got a warranty replacement from Napa. Another three months and it's making a rattling noise now - again, no dummy light or code - just noise.

Am I missing something or am I just unlucky or does Napa just sell garbage? Whirring and rattling are two different symptoms!

I have the day off tomorrow and I want to take care of this and I don't want it to happen ever again. I don't think Napa will give me my money back - just a replacement.

Do I install it?

Do I eat the $350 I gave Napa and go to the Chrysler dealer parts desk and pay what will certainly be $600+ for OEM?

Is there something I'm overlooking -- could a bad belt or tensioner be somehow eating alternators?

I appreciate the advice.