Solar panels produce DC electricity, which can be converted into AC electricity through an inverter for direct use by household loads. Extra DC electricity can charge batteries to serve as a backup at night or during rainy days. Inverters feature a state grid supplementing function; when battery power is insufficient at night, the state grid can directly power the load. Users can also choose to use the state grid to charge the battery during off-peak electricity price periods and sell surplus electricity back to the grid. For commercial and industrial solar hybrid systems, a diesel generator can be connected for additional energy backup.