I have little battery dock things, really dumb devices, but, USBC goes in, battery docks in, and it slow charges in about 8 hours. I've got 3 of them.
Also if you're talking about the world being dark for 3 years, not sure batteries are the thing to stock up on friend. We'd be well into mad-max mode after a few months I'd think, and after a year or so of that, well, nothing's going to come back for a good long time.
I'm much more concerned with making it, say, a week without being able to charge, which, I can easily do without thinking too much.
Also if you're talking about the world being dark for 3 years, not sure batteries are the thing to stock up on friend. We'd be well into mad-max mode after a few months I'd think, and after a year or so of that, well, nothing's going to come back for a good long time.
I'm much more concerned with making it, say, a week without being able to charge, which, I can easily do without thinking too much.