Low solar panel voltage can stem from various factors, including shading, dirt or debris accumulation, faulty connections, or even panel degradation over time. Why is inverter output voltage unstable? Actually, the large grid impedance probably cause inverter output voltage instability even the control loops are stable [ 59 ]. Electrical components' quality plays a significant role in ensuring stable. Why is solar voltage unstable? 1. Why do technicians call inverters the. Common faults discussed include panel degradation, electrical issues, inverter failures, and grid disturbances, all of which affect system efficiency and safety. While traditional diagnostics like thermal imaging and V-I curve analysis offer valuable insights, they mostly detect issues reactively.