You Do Need power plug adapter while traveling from Botswana to Slovenia.

Here is Why You Need An Adapter

The outlet and plug type used in Slovenia are C and F and in Botswana are D and G. This is how they look like.

Botswana

In Botswana, outlets of type D and G are in use.

Type D

Type G

Slovenia

In Slovenia, outlets of type C and F are in use.

Type C

Type F