The real advantage of this improved setup is also found in the analysis of the wall-plug efficiency (Table ). Due to the optimized induction coils, less power is needed for their upkeep and at the same time, the use factor in the WLEs is much higher. These two effects result in a significantly higher wall-plug efficiency of up to 34.0 %. This is remarkably high, considering that it comprises all losses from the power source, the wireless energy transfer, and the electrical efficiency of the LEDs themselves. Since the latter are rated at nominally 38.9% electrical efficiency, the overall loss of power source and wireless energy transfer is estimated at only 12.6% (87.4% efficiency). Interestingly, the overall energy efficiency in this case is also 2.5 times higher than for the case of external irradiation (vide infra).