We calculate the kinetic energy release distributions of fragments produced for electron-impact dissociation of the vibrationally excited molecular hydrogen ion H + 2 and its isotopologues D + 2 and T + 2 . Here we apply the adiabatic-nuclei convergent close-coupling method and compare results with several different methods, including the delta approximation. Results are presented for a number of dissociative excitation transitions and dissociative ionization as a function of the initial vibrational state of the molecule. We confirm that the "square root" approximation is a good approximation for the adiabatic-nuclei kinetic energy release cross sections of H + 2 . Agreement with experiment, where available, is good.