SMA America’s (sma-america.com) Smartformer enables the 120 VAC Sunny Island battery-based inverter to output either 120 or 240 VAC. The Smartformer also allows 240 VAC output Sunny Boy batteryless inverters to work with a single Sunny Island inverter for AC-coupled systems. Features include an integrated manual bypass switch, which directly powers loads from an alternate AC power source (such as the grid or a generator), should the Sunny Island inverter need maintenance or repair. The Smartformer specifications list a maximum efficiency of 99% and California Energy Commission-rated efficiency of 98.8%. Although its operating temperature range is -13°F to 122°F, it must be mounted indoors or in a weatherproof enclosure.