if you went camping on your own, you dont think you still need to recharge?

I think if you use the model presented by the author of the article, it's less than you need to "recharge" but rather that after a few days you've filled your small group and large group bucket/quota, and now you need to fill that solitude bucket/quota.

It's just two different ways of describing the same phenomenon. I like the authors because it's much more multi-faceted and easier to find practical applications, at least in my mind. "I enjoy a good amount of solitude, and I've just spent several days socializing, so I'm going to prioritize alone time for the next few days" rather than "I need to recharge so I can be social again." It's similar, but I like the first one better.