In order to control the aggregation phenomena in suspensions of nanoparticles, one often charges the particles electrically in order to delay or even suppress the aggregation process. The resulting cumulative size distribution of agglomerates of monopolarly charged nanoparticles suspended in liquid nitrogen is measured experimentally. The distribution is compared to results obtained by mean field theory. The relative width of the distribution obeys the lower bound predicted by theory. The results are discussed with respect to technical applications, e.g. stabilization of suspensions against aggregation.