Advanced meter infrastructures (AMIs) are now widespread and their importance within smart grid systems continues to increase with the advent of new applications. Performance analysis of the infrastructure is key to assess the limits of application deployment. However, due to the large-scale nature of AMI networks that are often composed of tens of thousands of nodes per collector, performance analysis is often carried out in contained experimental trials. To our knowledge, no thorough mathematical performance analysis of real-sized systems has been carried out so far. In this work, we present a model to analyze the performance of a large-scale RF-AMI system and show its application to large-scale real-case scenarios.