充电 does not mean recharge your batteries

Ok. So, obviously, literally, if you have a battery (电池) 充电 does mean to charge it, but that's as far as the metaphor goes.

The english (charge or recharge one's batteries) is not related 充电。

My notes/dict:

充电 = to brush up on, study up on something

from the chinadaily bbs, (yes, I know)

重新捡起以前所学到的知识

Seems about right to me. To go review something.