Life Expectancy of PV Inverters and Optimizers in Residential PV Systems

The average Time To Failure (TTF) of PV inverters and PV optimizers is investigated in this paper. The focus is on residential and small commercial systems. The data used in this paper includes 1195 PV systems consisting of 2121 inverters and 8542 optimizers. The data is obtained by means of an online survey sent to the system operators (343 systems) and by analysing system service databases of professional PV system installers and operators (852 systems). Since most of the systems examined are still in operation and have never failed so far, the results are presented using Kaplan-Meier survival curves. After 15 years, 34.3 percent of inverters show a first failure. The most important factors influencing the TTF are the installation location of the inverter (indoor installations have a lower TTF than outdoor installations), the manufacturer and the inverter topology (installations with optimizers have a lower TTF than installations without optimizers).