This thesis focuses on the EVERGRIN project, which is being developed by Brain Technologies with the aim of converting internal combustion engines into full electric vehicles. The project involves the creation of a set of components that can transform a traditional car engine into a more environmentally friendly alternative. Specifically, this thesis focuses on the design of the Power Box, updating and modifying the Electrical schematics to integrate the new SME inverter. The Power Box is a key component in the transformation process and requires careful design and assembly to ensure it functions effectively. This thesis work aims to provide a detailed overview of the Power Box design process, as well as the necessary modifications to the electrical schematics to accommodate the new inverter.