We have calculated impact ionization (II) and Auger recombination (AR) lifetimes in hot carrier solar cells (HC-SCs) in operation, and found that these lifetimes are much longer than the average retention times of photo-generated carriers in the cells at an appropriate range of applied voltage, under practical conditions of 500-1000 times-concentrated solar irradiation and carrier thermalization times of several hundred picoseconds. This means that the particle conservation (PC) model, in which II and AR are completely excluded, can be applied to predict the conversion efficiency. In contrast, the PC model does not stand under the ideal condition of the maximally concentrated irradiation and no thermalization of carriers, as previously pointed out. (C) 2008 Elsevier B.V. All rights reserved.