Patent ID: 8143741

Claim:
An electric power generation control device driven by an internal combustion engine mounted on a motor vehicle, for generating electric power and determining a power generation voltage for supplying the electric power to an electrical load and electricity storage means of the vehicle, comprising: electricity storage amount detection means for detecting an amount of electricity stored in the electricity storage means; power generation voltage decreasing means for lowering the power generation voltage when a predetermined electricity storage amount is detected by the electricity storage amount detection means; lighting detection means for detecting lighting of a headlight bulb of the vehicle; sunlight state detection means for detecting a state of sunlight; and control means for restraining the power generation voltage from being lowered by the power generation voltage decreasing means if the sunlight state detected by the sunlight state detection means is equivalent to nighttime while lighting of the headlight bulb is detected by the lighting detection means, allowing the power generation voltage to be lowered by the power generation voltage decreasing means if the sunlight state detected by the sunlight state detection means is equivalent to daytime while lighting of the headlight bulb is detected by the lighting detection means, and allowing the power generation voltage to be lowered by the power generation voltage decreasing means irrespective of the sunlight state while lighting of the headlight bulb is not detected.