In this paper, we present an iterative computing method to illustrate the discharge, recovery and charge process of general lithium/lithium-ion batteries. The discharge and recovery processes correspond well to an existing accurate analytical battery model: the RV- W?s analytical model, and thus interpret this model algorithmically. Our method also extends R-V-W's model to accommodate the charge process. The work will help the system designers to grasp the characteristics of R-V-W's battery model. Experiments are performed on a variety of load profiles to show the accuracy of the extended model by comparing the predicted charge time with that derived from the DUALFOIL simulations.