Low-Cost Arduino-Based I-V Curve Tracer with Automated Load Switching for PV Panel Characterization

Accurate photovoltaic (PV) panel characterization under real environmental conditions is critical for optimizing renewable energy systems. However, commercial I-V curve tracers are often expensive, inflexible, and unsuitable for rapid field deployment. This paper presents a low-cost, Arduino-based data acquisition (DAQ) system capable of real-time I-V curve tracing using automated resistive load switching in a single microcontroller. The system integrates current and voltage measurements with a relay-controlled resistor bank, enabling sequential load variation without manual intervention. A total of 23 unique resistor combinations were programmed, providing fast and granular coverage of the PV panel’s operating range. Experimental validation was conducted on a commercial PV panel under natural sunlight conditions. The system total data acquisition time was 45 seconds and achieved high agreement with a single-diode PV model, with a mean absolute percentage error (MAPE) of 4.40% under standard conditions (manufacturer’s data). When re-optimized with field-acquired data, the model’s accuracy improved significantly, reducing the MAPE from 18.23% to 7.06% under variable irradiance. This open-source solution provides a cost-effective, portable, and scalable alternative to commercial tracers, with potential for integration into IoT-enabled PV monitoring platforms. Its design supports research, education, and deployment in low-resource environments where accessible renewable energy diagnostics are essential.