Experimental multi-level calibration of a silicon mini solar cell for low-cost solar irradiance measurement

Accurate assessment of photovoltaic potential is essential for optimizing system integration at specific sites, requiring precise measurement of ground-level solar irradiance. However, commercially available irradiance sensors are often costly, limited in configurability for research, and require specialized calibration tools. To address these challenges, this study presents the design and development of a portable, energy-efficient, cost-effective irradiance measurement system. The device employs a small polycrystalline solar cell as the sensing element and a 10-bit microcontroller for data acquisition. Irradiance values are calculated using an established algebraic relationship between the solar cell’s short-circuit current and incident solar radiation. The sensor was then evaluated outdoors under clear-sky and partly cloudy conditions using a commercial handheld irradiance meter for comparison. Within the investigated dataset, the developed sensor showed a linear response across the tested irradiance range. The mean percentage deviation was 0.84% under clear-sky conditions and 3.11% under partly cloudy conditions, with maximum deviations of 15.5 W/m² at 491 W/m² and 12.5 W/m² at 130 W/m², respectively. These results indicate that, within the tested irradiance range and experimental conditions, the proposed low-cost system can provide consistent irradiance measurements suitable for experimental monitoring and preliminary PV site assessment.