Not charging with headlights on

Speaking of the bulbs... and this is OEM sealed beams with 3 male lugs attached on the back. I once found a lug snapped off a bulb and touching the lug beside it. The short/cross feed was powering high beam and low beam, 3 out of 4 anyway, at the same time, all the time. After discovering the fault, I learned that this car had been in a fender bender. The body man didn't notice this little fault. He wasn't supposed to.
Our old Chryslers have so many typical charging system issues that we pretty much assume the typical culprits, amp gauge connections, firewall connections, etc... Story above was just to say other not so typical culprits are possible.
In this case I would first test the alternators output or have it tested. Might be just a bad diode or something. Good luck with it.