The System Info inputs describe the physical characteristics of the photovoltaic system. You only need to provide basic information about the photovoltaic array. PVWatts® makes assumptions about modules, inverters, and other parts of the system so you do not need to provide detailed information about those parts of the system.
Important note. PVWatts® uses a set of assumptions that are appropriate for flat-plate photovoltaic systems with typical crystalline silicon or thin-film modules. PVWatts® results are not appropriate for systems using some types of thin-film modules, concentrating collectors, or for modules using novel cell technologies or module designs. See Module Type for details.
The advanced parameters are assumptions that you can change when you have additional information about your system. For most analyses, you can ignore the advanced parameters and use their default values.