Grid Tie with Battery Backup
As power disruptions become more frequent, there is a growing desire for solar electric systems that provide power during utility power outages. For the safety of line workers, grid-tied solar electric systems must not feed power back into the utility lines during an outage. Battery-less inverters simply shut down when the power goes out. Grid-tied battery based inverters include a transfer switch to isolate them from the grid and use a battery bank to supply power to loads designated for backup and connected to a separate output from the inverter.
There are several ways to design and deploy inverters with backup capability. Means of connecting the backup loads to the system can range from simple to complex. Backup power can be arranged for longer or shorter times depending on the loads and battery bank capacity.