This study presents experimental investigation and analysis of electrochemical impendence spectroscopy (EIS) of a newly developed photoelectrochemical (PEC) cell for hydrogen production in no-light and concentrated light illuminations. The application of EIS analysis indicates the main internal charge transfer resistances which limit the performance of the cells with copper oxide (Cu2O) as the photocathode. An experimental setup is built to investigate the concentrated light conditions on the cell performance and obtained results are compared with dark conditions. The equivalent electrical circuit is modeled for the developed photoelectrochemical cell and fit the experimental data. Operating at concentrated light conditions increases the effect of mass transfer which lowers the Warburg element values under concentrated light measurements. The current results reveal the distribution of the losses occurring in the cell. This study assesses the PEC cell under concentrated light conditions comparatively for understanding the processes occurring at higher concentration levels.