The present invention relates to a converter unit for providing a supply current to a load device (2) using an energy storage device (6). The converter unit (1) comprises a controlling means (7) configured to set at least one charging parameter and/or a charging mode and to control charging of the energy storage device (6) based on the set charging parameter and/or the set charging mode; and at least a first terminal (S1), a second terminal (S2) and a third terminal (S3) for electrically connecting a two-pole status indicator light (8), wherein the controlling means (7) is configured to detect to which of the first terminal (S1), the second terminal (S2) and the third terminal (S3) the two-pole status indicator light (8) is connected and is configured to set the at least one charging parameter and/or the charging mode based on the detection result.