Method: Energy required = appliance load × runtime. Battery capacity includes the selected battery reserve and assumes 90% inverter efficiency. Solar panel capacity is based on the energy required, available peak sun hours and an assumed 80% overall solar charging efficiency. Recommended inverter capacity is based on the continuous appliance load with 25% headroom. If a startup / surge load is entered, the generator should support at least that surge power. Actual solar charging and runtime vary with weather, panel orientation, battery condition, temperature, inverter efficiency and equipment limits.