Reliable values of the Hall scattering factor of 4H SiC are obtained by measurements on four n-type 4H SiC homoepitaxial films over the temperature range 40-290 K using magnetic fields up to 30 T. Good fits are obtained to the measured temperature dependent Hall mobility using a simulation that includes the inelastic process of polar optical phonon scattering without recourse to the relaxation time approximation. Two deformation potentials are the adjustable parameters. The model is tested by comparing calculated results, with no further adjustments of the parameters, with the measured temperature dependence of the Hall scattering factor.