A load calculator detects a specific electric amount separately from an essential
electric amount. The specific electric amount represents an electric power consumption
of specific electric loads including at least one economizable electric load which
is selectively turned on and off so as to serve as an objective to be economized
in power consumption. The essential electric amount represents an electric power
consumption of essential electric loads which are not economizable and essentially
required for driving an automotive vehicle. A power saving promoting element promotes
power saving by reducing power consumption in the economizable electric load with
reference to the specific electric amount.
