Recently, the usage of portable electronic gadgets such as laptops and mobile devices has grown massively. These developments have led to an alarming increase in demand for rechargeable batteries. Benefits of lithium-ion batteries include but are not limited to high operating voltage, high energy density and low maintenance because it has no memory making it the most widely used rechargeable battery in today’s electronic industry . With Li-ion batteries being in such high demand, numerous researches have been conducted to develop a suitable charging system for them. In recent times, majority of these researches have been focused on charging the lithium-ion battery for automobile application. In this paper, a single-output charger for charging lithium-ion batteries of different specification is presented and simulated. A TTC dynamic model of Li-ion battery is modeled in MATLAB/Simulink. A DC–DC buck converter is designed and a PI controller is integrated into the system for stabilizing the output. The novelty of the proposed system is that it can be used to charge multiple devices sequentially. From the experimental results obtained, the proposed charging system has the ability of charging Li-ion batteries of laptops and mobile phones with a current ripple of less than 1%.