The battery charging apparatus is made with small and low-cost components. It includes a first transistor (T1) with a control input through which the charging current flows into a battery (B) and a current source (T3, T4, R1, R2) for a control current flowing to the control input of the first transistor. The current source sets or adjusts the control current so that the first transistor is non-conducting or blocked and the charging current flowing into the battery is shut off when a predetermined maximum charging voltage is reached at the battery.