PURPOSE: To eliminate contract limit of a current with an electric power supply company if a charging stand is connected to a domestic commercial power source by supplying a total current of a discharging current from an electric double layer capacitor and a current from the commercial power source.
CONSTITUTION: Since a portable power source B has a backup power source capacitor 12 if the source B is connected to a charging stand A, a large current is requested to the stand A to charge it. However, since an electric double layer capacitor 8 of the stand A is already charged, a large discharge current flows from here toward the capacitor 12. That is, the total current of the current from the commercial power source and the discharge current is supplied to the source B. Accordingly, even if a current exceeding the contract limit is not drawn from the commercial power source, it can respond to the request of the source B.
KURABAYASHI KEN
TSUCHIYA YOSHINOBU
