Modern lithium ion batteries such as LiFePO4 are an active topic because of their good parameters. Yet as all lithium based batteries they need battery management systems for proper operation. The design and testing of such systems is very time consuming and additionally the cell testing and deep discharge or full charge can become dangerous because of cell operational limits. Typically battery models are used for simulation of such systems, yet the manufacturers do not provide all the necessary information to construct the models. This article is intended to provide some information such as cell capacity dispersion and open circuit voltage necessary for the development of a cell model. The same information can be used to develop state of charge estimator as well.