I'm an introvert to the extreme so my social battery is on the lower side, I'd say (though I'm not sure how much of that is from being introverted and how much it is just having low patience for rude people). I can power through and hide it pretty well if I have too though. I can handle a full day, maybe a day and a half, of a bunch of big social things before I absolutely need time to myself for a break, but it really depends on what that social thing is. For example, school every day was very rough on me, but going out with friends for a whole weekend was more then fine.
One thing I've found that helps is Planning. It. Out. What day is this happening on? What time does it start? Do I have to go anywhere or is it at home? When does it end/when is it acceptable to go home? My parents and I started doing it this way originally because as a kid, I had a lot of doctors appointments we needed to work around so having all that info was ideal, but as I got older I found it really helped in making sure I had the energy I needed and that I was mentally prepared for other things too.
When it comes to recharging I need to be left alone in my own space. I can't have people near me, even to just check on me, or I'm sure to have an overstimulated breakdown. When my battery is depleted everyone is too loud, too rough, too much. I normally just go into my bedroom put on some soft music, grab a book and my weighted blanket and stay there for an hour or two, possibly longer if needed. Or I just straight up take a nap.