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

Here is Why You Need An Adapter

The outlet and plug type used in Peru are A, B and C and in Slovenia are C and F. This is how they look like.

Slovenia

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

Type C

Type F

Peru

In Peru, outlets of type A, B and C are in use.

Type A

Type B

Type C