Good morning oppo, last night I went out to my 1981 280zx to go pickup my roommate from jail and I realized that I had left an interior light on and my battery was dead. After a jump, I drove down the hill in front of my house and the car died again. I re-jumped it and noticed that turning the headlights on drops the RPM enough to kill the engine. Even idling with an interior light on slowly drained the battery. My assumption is that this is an alternator issue and the battery is simply not charging after the jump start but I figure it could also be a really gnarly short somewhere. Brake lights and parking lights also drop the RPM but by a lower amount. I don’t think the battery is the issue although I have no idea how old it is so I could be wrong. What say you oppos?