He made the generator. Because there was no electricity in ancient times, the generator made by Xiaochuan is OK because the schematic he drew and the materials he found are correct, and it produces alternating current (AC) electricity, which meets modern charging rules, and can only be connected to two wires to charge the positive and negative terminals of a battery. The ones I've tried charging MP3 batteries before are
rechargeable batteries
, all the same type, and can't be charged by putting them directly into the cell phone hole because the charger charging end is specially made to be inserted into the metal tip of the jack and the rounded portion at the back that connects to the cell phone's positive and negative terminals, respectively. But the TV show still has a slip-up, because he charges the phone directly, not the battery.