Battery charging device and method of controlling battery charging device

A method of controlling a battery charging device that comprises:

• a conversion part that converts an alternating current output from an alternating-current generator into a direct current by a switching element and supplies the direct current to a battery;
• a number-of-revolutions acquisition part that acquires a number of revolutions of the alternating-current generator based on a signal responsive to the operation of the alternating-current generator;
• and an output control part that determines an energization phase angle that defines a timing of energization of the switching element of the conversion part for supplying a charging current from the alternating-current generator to the battery and controls energization of the switching element based on the energization phase angle, the output control part having a table that defines a relationship between the charging current of the battery and the energization phase angle and a relationship between the number of revolutions of the alternating-current generator and a correction value with which the energization phase angle is corrected in response to the number of revolutions,
• wherein the output control part acquires the energization phase angle and the correction value by referring to the table for the charging current to be output and the number of revolutions acquired by the number-of-revolutions acquisition part, and corrects the energization phase angle with the correction value.