Over the coming years, major growth in the use of Li-ion batteries is expected, both in electric mobility as well as in stationary applications, be it in self-consumption systems and micro grids or in large renewable power generation plants. The proper characterization of lithium-ion cells is of vital importance for the development of precise models that permit the simulation and prediction of their behavior, so as to suitably configure cell groupings for the resulting battery packs, and to properly select the most suitable cells from the extensive manufacturer offer. In this work, an analysis is conducted of the main techniques used in the literature to characterize batteries. Also, an experimental comparative is carried out on 18650 Liion cells from three large global manufacturers, focusing on the primary methodologies used to characterize capacity, internal resistance and open circuit voltage. Finally, the advantages and disadvantages are presented for the methodologies used, based on the experimental results obtained. The authors would like to acknowledge the support of the Spanish State Research Agency (AEI) and FEDER-UE under grants DPI2016-80641-R and DPI2016-80642-R and of Government of Navarra through research projects PI020 RENEWABLE-STORAGE and 0011-1411-2018-000029 GERA.