I've been searching for information all over, and it's surprisingly hard to find the details. I see that sodium is much better than lead but not as good as lithium, but cheaper and nontoxic, so I went looking for why Pb batteries aren't dead yet and replaced by Na everywhere.
Looks like the alternators will have to be replaced (or can they be reprogrammed?). Any mechanics or engineers here have additional insights?
Also should be applicable to UPS batteries. Anyone building those?
I suspect the engineer approach would still be to demand a brick of standard lead-acid battery size, to fit into the hole, and the least possible change to wiring harness and associated behaviour.
Building out cars which need a different box in the hole would be something you do with supreme confidence it isn't making you awkward in the marketplace. If you wind up at the petrol stop in death valley with a dead battery, and alas a good ol' lead acid unit can't fit, that isn't cool. Battery replacement happens in all kinds of places.
I guess being years ahead of the US in modern tech, including drones with a government made from mostly ENGINEEERS and SCIENTISTS.