<p>This article investigates the problem of improving energy utilization efficiency in a power supply system based on a solar panel and a battery. Variations in solar irradiance and temperature over time affect the stability of the solar panel’s </p><p>output power and require accurate maximum power point tracking. To address this problem, a Perturb and Observe (P&O) algorithm and a fuzzy logic-based control method using a ZETA DC–DC converter were compared. In the study, a </p><p>system consisting of a 2 kW rated solar panel, a ZETA converter, and a lithium-ion battery was modeled in the Simulink software environment. The control algorithms were evaluated under varying solar irradiance and temperature conditions, and </p><p>their ability to maintain the solar panel’s output power close to its maximum value was analyzed. The results demonstrated that both methods are effective in extracting maximum power. At the same time, fuzzy logic-based control adaptively </p><p>regulates the converter duty cycle by taking into account the power error and its rate of change. This enables stabilization of the energy flow, reduction of power fluctuations, and improvement of the battery charging process. The proposed </p><p>approach is of practical significance as an effective control solution for autonomous solar energy systems.</p>