Opening Vendor-Locked Telemetry: Non-Intrusive Decoding of Solar Inverter IoT Communications in Restricted Environments — A Case Study

Abstract

Commercial solar inverter systems rely on vendor-controlled cloud platforms to manage telemetry, data access, and device configuration. In restricted environments, however, a lack of administrative access prevents end users from retrieving operational data, compromising system transparency, trust, and the ability to perform independent monitoring. This paper presents a secure and vendor-independent method for acquiring telemetry from IoT-based solar inverters by intercepting and decoding proprietary communications between inverters, dataloggers, and the cloud. We deploy a Raspberry Pi as a passive network probe connected to the same gateway used by the vendor's dataloggers. Through controlled network sniffing, encrypted frames are captured, reconstructed, and reverse-engineered to extract operational variables without interacting with or disrupting the proprietary platform. The decoded data are forwarded securely via HTTPS to an institutional backend, where they are stored and visualized through a custom telemetry dashboard. Our results demonstrate the feasibility of trusted, transparent, and secure telemetry extraction in IoT energy systems when vendor cloud access is unavailable-offering a practical pathway toward resilience, auditability, and user sovereignty in constrained IoT environments.