It's not clear. It's possible that even if you don't use the fitness at all, you'd still have to plug in once a month. Or maybe your situation would work, i.e.

It's not clear. It's possible that even if you don't use the fitness at all, you'd still have to plug in once a month. Or maybe your situation would work, i.e. it could regenerate an hour worth over the span of a week.