In this study, the Perturb observe controller and PI controller for a Li-Ion battery charger with photovoltaic panel sourced is proposed. Compared with other batteries, Lithium-Ion (Li-Ion) batteries are featured by high-energy, high-power, long-life and environmental-friendliness and therefore have found wide application in the consumer electronics. The voltage and current of PV panels are nonlinear and variable environmental conditions cause to change voltage and current. They also cause to change maximum available power of PV panels. Maximum power point tracking (MPPT) methods are used to obtained maximum power and to increase efficiency of the photovoltaic panels (PV). The charger topology consists of two-stages: 1) a photovoltaic panel source DC-DC boost converter to obtain the high output voltage, and 2) a half-bridge bidirectional DC-DC buck-boost converter to behave as a charge controller. The perturb and observe (P&O) controller is used to obtained maximum power and voltage of the photovoltaic panel (PV) system. The constant voltage method with PI controller is used for bidirectional DC-DC buck-boost converter to charge of a Li-Ion battery. PI controller is a simple technique and also it provides satisfactory results. The simulation of the 5 kW photovoltaic panel, DC-DC boost converter and charger are created by using of computational blocks and design suit blocks in PSIM circuit simulations.