A battery charging apparatus includes a charging power source, a plurality of charging circuits, a plurality of batteries, a plurality of switching circuits and a control circuit. The control circuit is configured to determine the type of charging power source based on a current-voltage curve of the charging power source, and to control conduction states of the switching circuits to connect the charging circuits and the batteries in series in a series charging mode and to connect the charging circuits and the batteries in parallel in an equalizing charging mode. A battery charging method of the battery charging apparatus is also introduced.