This is an online-interactive program that walks the user through the sizing of solar array strings. It has a data base of inverters and panels making it possible for the student to experiment with different sizes and configurations. It also integrates weather in the location (by zip code) allowing students to consider that variable. A useful tool for solar array installation. Limited to Sunyboy inverters and may be a little dated as none of the larger panels are represented. Provides nothing that a normal analysis of voltage High and Low limits of the inverter, divided by the voltage of the PV panels would give. Usable to people who don't understand the series type connections.