This paper presents a fast and safe quasi-optimal multistage constant current (MCC) charge pattern optimization strategy for Li-ion batteries. It is based on an integrated electro-thermal model that combines an electrical equivalent circuit (EEC) battery model with a thermal battery model. The EEC model is used to predict the battery’s terminal voltage continuously as charging progresses, while its temperature rise is also estimated continuously by employing the thermal model. This integrated electro-thermal battery model is utilized to search for an optimal MCC charge pattern that charges the battery in minimum time, while simultaneously limiting its temperature rise to a user-specified level. The search for the optimal charge pattern is carried out on a stage-by-stage basis by using a single-variable optimal search strategy that can be easily implemented on a battery management system. The paper also includes some simulation results obtained from an integrated electro-thermal model of a commercially available medium-power Li-ion cell. These results indicate that the proposed quasi-optimal MCC charging strategy performs as expected and can serve as a useful, easy-to-implement alternative to existing computationally intensive optimal charge strategies proposed by other researchers.