Huawei's Backup Box provides automatic detection & switchover providing reliable backup power.

It's used in a residential rooftop PV system to control the inverter, grid-tied or off-grid. When the grid fails, the inverter switches to the off-grid state and supplies power to off-grid loads in backup mode. When the grid recovers, the inverter switches back to the grid-tied state.

The Box is compatible with the following Huawei Inverters: SUN2000-2/3/3.68/4/4.6/5/6KTL-L1