Sunny Boy Storage Automatic Backup Unit

Additional peace of mind with SMA residential storage solutions 

The new SMA Automatic Backup Unit is an automatic transfer switch designed specifically for use with the SMA Sunny Boy Storage inverter family. In the event of a grid failure, the automatic transfer switch disconnects the PV system, loads and the Sunny Boy Storage from the utility grid and creates a battery-backup grid. The included Backup Unit Controller coordinates grid disconnection and reconnection to ensure minimal downtime while also allowing for up to 5 kVA of unbalanced loads. When paired with SMA Sunny Boy inverters, the Sunny Boy Storage curtails PV power production to match load in the event the battery is full to maximize use of solar production. The Automatic Backup Unit can be installed in a wide variety of installation types which makes for a versatile tool.


  • Suitable for many use cases including whole house backup or connected to a protected loads panel

  • Allows for direct connection of PV and Sunny Boy Storage inverters


  • 200 Amp rated bus allows for large panels to be connected to it

  • Up to 5 kVA of unbalanced load

  • Outdoor rated for harsh environments

Simple Installation

  • Pre-wired and tested to make for easy commissioning

  • Plug-n-play installation with Sunny Boy Storage inverter

  • Easy setup and commissioning via Sunny Boy Storage webUI


  • AC coupled architecture allows for new PV or retrofit installations

  • Up to three high-voltage batteries can be connected in a single SMA residential storage solution


Data sheet