This document summarizes improvements made to the System Advisor Model (SAM) for predicting photovoltaic module performance based on IEC-61853 test data. A new model was developed that estimates module parameters at any test condition or operating condition, resulting in an 88% reduction in error compared to the previous 6 parameter model. The updated model and its ability to more accurately reproduce module test data from the improved parameter estimation technique will be available in SAM around July.