Abstract—The validation of renewable energy systems and battery technologies is challenging due to the dynamic and non-ideal behaviour of real-world loads. This study presents a programmable load solution designed to emulate such loads using FET switches and passive components, controlled by an STM32 microcontroller for precision and reliability. The system operates in multiple modes, including Constant Current (CC), Constant Voltage (CV), Constant Resistance (CR), Constant Power (CP), and energy source profiling with a maximum voltage of 100V and current capacity of 50A, incorporating overcurrent and overvoltage protection for safety. It supports the validation of diverse power sources such as Switched-Mode Power Supplies (SMPS), battery chargers, and renewable energy systems, while providing real-time data logging and remote monitoring for detailed analysis. This solution reduces testing time and costs by enabling efficient, automated testing and characterization, offering flexibility for various scenarios and ensuring the quality, reliability, and performance of DC-DC converters and renewable energy systems.