Another of the Ball's priorities was to have access to backup power in the event of grid failure, however, the options of a grid-tied battery back up or an AC coupled system were out of the budget.
At this time, SMA had just developed their new Sunny Boy TL-US inverter with a function called Secure Power Supply (SPS). Typically in a grid failure, the inverter will turn off for safety reasons and the homeowners will not be able to use power from the solar array until the grid comes back online. SPS, on the other hand, can provide up to 1,500 watts of power to a dedicated outlet in the event of grid failure simply by turning the SPS outlet on.
Through SMA's Sunny Pro Club, OnSite Energy was able to access a pre-release beta test inverter to use for this installation, and the Ball's were happy to have their installation be the "test run" for this new exciting step in solar technology.
Some of the limitations of SPS are that it only works during the day with adequate sunshine, and can only provide up to 1,500 watts. In the event of grid failure, this would allow the homeowner to maintain smaller loads such as charging electronics or powering an internet router. With hopes to one day be able to power their entire load when the grid goes down, the Ball's system was designed to accommodate for adding battery back-up capabilities in the future.