Large polycrystalline CdTe charges for the subsequent growth of CdTe and CdZnTe crystals were prepared by the traveling heater method (THM). The composition of the produced material was evaluated by vapor pressure scanning (VPS) analysis. Results from these analyses were instrumental in improving the THM CdTe compounding process. The optimization of THM process parameters, such as the compounding rate and the loading configuration of the synthesis crucible, led to the preparation of polycrystalline CdTe ingots with small deviation from stoichiometry. For five out of six analyzed samples, tellurium content between 50.0012 and 50.0043 at. pct was achieved, which is well below the tellurium saturation limit of the single-phase solid in equilibrium with the molten zone at the chosen THM process temperature.