Results for our models without dust evolution, with truncated-MRN (100−250 nm) (top) and MRN (5−250 nm) (bottom) size distributions, both covered by icy mantles. Left: evolution of the fractional abundances of charged species: ions, electrons, negative charges (g-) and positive charges (g+) on grains. Centre: evolution of the dust parallel conductivity (σ_g∥), dust perpendicular conductivity (σ_g⊥), ion perpendicular conductivity (σ_i⊥) and Hall conductivity (σ_H). Scalings in powers of n_H are over-plotted in dotted lines for an easier comparison of our numerical results with the asymptotic trends described in Sect. 4.1). Right: evolution of the Ohmic (η_Ω), Hall (η_H), and ambipolar diffusion (η_AD) resistivities.