Method for Checking a Primary or Secondary Unit of an Inductive Charging System

A method for checking a test secondary unit of an inductive test charging system for charging an electrical energy store, wherein the test charging system comprises the test secondary unit having a test secondary coil and a reference primary unit having a reference primary coil, includes recording a plurality of actual primary unit impedance values of the test charging system at the reference primary coil for a corresponding plurality of test combinations of values of operating parameters of the test charging system. The method also includes comparing the plurality of actual primary unit impedance values with a reference value range for a primary unit impedance.