This study presents the design, fabrication, and performance evaluation of an in-house constructed mixed-mode active-type solar dryer, incorporating two double-pass solar air collectors connected in series, a drying chamber equipped with a tray, a 0.5 hp. blower, and a 1.25 kVA solar off-grid system. The dryer was subjected to thermal performance assessment under no-load conditions following a generalized heat balance approach. A non-dimensional parameter termed the no-load performance index (NLPI) was introduced to characterize the system’s thermal performance. The NLPI was found to be largely independent of incident solar radiation intensity and ambient air temperature for a given airflow condition, thus serving as a reliable metric for comparing solar dryers with varying configurations. The experimental results demonstrated an average NLPI value of 2.21, which is significantly higher than previously reported values in the literature. Additionally, the dryer was tested for its efficacy in drying seedless grapes. The initial moisture content of 74% (w.b.) was successfully reduced to 13.44% (w.b.) within 31 h, outperforming open sun drying, which achieved only 40.67% (w.b.) reduction over the same period. These results highlight the potential of the developed dryer for effective utilization by small-scale farmers, with scalability for larger applications.