The voltage at which the solar panel is designed to operate is known as nominal voltage. A modern 2026 solar panel has three voltage numbers on its datasheet, and they all matter for different reasons. The difference between 12V, 24V, and 48V solar setups. What Is Solar Panel Voltage? Simply put, voltage (V) is the electrical potential or. When sunlight hits a solar panel, the photovoltaic effect causes electrons to move, creating an electrical pressure that is generally referred to as the solar panel voltage and is measured in volts. Think of voltage as the pressure in a water pipe; the higher the pressure, the more water flows through the pipe. However, the answer is not straightforward.