The PV behavior is modeled by sub cell method with the subcell and the internal work load decay playing the key roles. The method generates easy to apply analytical results such as MPP and IV characteristic of PV without the need of equivalent circuits. The results are consistent with these of the general IV approach. The sub cells modeling interprets the mechanism of maximum power and MPP in a geometric way independent of the physical detail of PV cells. The method can be applied in areas beyond PV. (C) 2015 Elsevier Ltd. All rights reserved.