As it happens, I've spent a lot of time over the last week talking to a guy in Romania who's trying to fix a sulfated lead-acid battery in his backyard garage. (I don't know if you've been to Romania, but the apocalypse happened 40 years ago there, so his available resources are kind of limited.) I think he's going to succeed, and may eventually progress to being able to recycle the lead into a new battery, but it's not going to be a weekend learning process or even a week-long one.

What kind of apocalypse happened in Romania 40 years ago?

I presume he's talking about the collapse of the Soviet Union, which caused a huge amount of upheaval in that area.

But I'm a poor student of modern history. Just throwing out a guess for now.

That sounds like the opposite of an apocalypse

Eventually it was good for Romania but IIRC, the initial collapse was very bad for the locals.

But again, I'd say that Eastern European modern history is my weakest subject by far. I probably should avoid talking about this subject lol.

Right, but I got the time interval wrong; it was only 30 years ago.

And in a Mad-Max future (lots of cars around, but not enough fuel), there will be plenty of Lead Acid batteries laying around to recycle.

I do consider it effectively an apocalyptic kind of battery design. It was invented in the 1800s, its chemistry is incredibly simple (Sulfuric Acid + Lead), and is very well studied.