Dramatic photovoltaic (PV) module cost reductions have enabled solar to reach economic viability in some applications, but further improvements are needed to achieve wide spread global adoption. In addition to further cost reductions, high PV penetration requires smart grid functions with the ultimate goal to integrate low cost battery storage with intermittent solar generation plants. Both PV modules and battery costs are dropping, but power converters and Balance-of-System (BOS) cost are increasingly a cost and efficiency bottleneck in both types of systems. When PV and battery systems are used together the power converter related costs ($/W) and efficiency losses can be doubled, as multiple power converters and multiple power converter steps are required. Ideal Power Converters (IPC) has developed and patented a new indirect power converter topology. Its initial product, a 30kW 480Vac commercial PV inverter, is now shipping and has won multiple industry awards including ARPA-E grant by dramatically improving the weight/size, manufacturing cost, efficiency, and reliability. A key benefit of IPCs indirect power transfer topology is its ability to support multiple independent DC and AC ports in a single-power converter, which has not yet been demonstrated. This Phase I SBIR will help fund development of a revolutionary 30kW 480Vac 3-Port PV & amp; Battery Converter, which will be prototyped and delivered to the National Renewable Energy Laboratory (NREL) for initial testing and validation. IPCs converter will deliver & gt;96% efficiency between any of the three ports and with only a modest increase in manufacturing cost over its initial low cost 30kW PV inverter. The 3-port converter will eliminate the power converter cost and efficiency penalties of combined PV and battery systems. Phase II will develop new advanced control capabilities for micro-grids and utilities meeting industry standards. Commercial Applications and other Benefits Improving the system cost and efficiency of combined PV and battery systems will accelerate adoption in several billion dollar markets. The application discusses three markets for the 3-port converter which IPC is already working with system integration partners and with Letters of Support included. These are 1) high power electric vehicle charging infrastructure with lower operating costs and Vehicle-to-Grid capabilities (NREL), 2) PV smoothing and peak demand reduction for grid-storage (Johnson Controls), and 3) replacing off- grid diesel generation with PV and batteries for DOD Operations and remote cellphone towers (Tesla Industries).