Patent ID: 7414332

Claim:
An electric power unit, comprising: a plurality of electric sources; a plurality of electric source lines connected to the plurality of electric sources, respectively; a discriminating device configured to detect about whether or not at least one of the electric source is connected to any of the plurality of electric source lines; a selecting device configured to select one of the plurality of electric source lines as a using electric source line; a first discharging device configured to discharge a residual electric charge in each of the plurality of electric source lines from the electric sources to the selecting device; a second discharging device configured to discharge a residual electric charge in each of the plurality of electric source lines after the selecting device; and a detecting device configured to detect any of the residual electric charges on the electric source lines from the electric sources to the selecting device and after the selecting device, wherein the discriminating device is configured to discriminate the electric source connected to the electric source line, based on the discharge of the residual electric charge in each of the plurality of electric source lines from the electric sources to the selecting device, the discharge of the residual electric charge in each of the plurality of electric source lines after the selecting device and the detection of the residual electric charge in each of the plurality of electric source lines after the selecting device, and the selecting device is configured to select the electric source line discriminated by the discriminating device as the using electric source line.