Cracked Up: how should we classify and respond to various electroluminescence defects in silicon PV modules?Presented at the 2019 PV Reliability Workshop, PVRW, Feb 27, 2019 In EL testing of modules, there is little in the literature to guide one on when to test these modules, how to enhance & interpret the EL images, how to classify and quantify various types of defects, and in particular on how to respond to these defects in different situations. We suggest solutions to these issues for different scenarios. We show various cell processing defects that can be confused for cracks and suggest ways to better differentiate between cell defects and cracks. We suggest ways of quantifying the crack statistics and ways to respond when those statistics fall within different ranges. We also discuss the possibility of various in-field repairs or panel enhancements to reduce degradation rates.