The Kirchhoff-Law-Johnson-Noise (KLJN) key exchange protocol had been introduced as an ultra-low cost alternative of quantum cryptography. Two years ago we have developed a generalized version of the KLJN key exchanger (VGM-KLJN), and we have proved that the system works perfectly secure under much more general conditions that allows compensation of many kinds of imperfections. In this work we focus on the experimental analysis of our recently introduced VGM-KLJN system. We determine the time required to transfer a bit, the error rate of the information transfer and we also evaluate the probability of successful eavesdropping in the case of different imperfections of the components. We demonstrate a method of real-time identification and compensation of these imperfections. The results of our analysis can greatly aid practical applications and at the same time can serve as a guide to design a system with the required security level.