The diploma thesis on the topic of evaluation of cordless portable chain saws during mining activities is processed in connection with the bachelor's thesis. The diploma thesis analyzes the history, development and description of the accumulator and accumulator portable chain saws. The advantages and disadvantages of cordless saws were evaluated in this work. We also focused on batteries of portable chain saws, which are very widely used today and are often used. We carried out an experiment aimed at determining the battery life of a Husqvarna 536 Li Xp, cordless portable chain saw. The research was carried out during all seasons and during different external conditions. At the end of this work, the experiment and recommendations for the user are evaluated.