Autonomous vehicles are already being produced today and it is a market on the up rice. To ensure a safe drive for heavy autonomous vehicles, it’s vital that faults are handled automatically. Critical errors have previously been handled by the vehicle's driver. An attractive way to ensure automatic handling of faults is an autonomous vehicle constructed with several redundant systems. The aim of this project has been to investigate the expansion of Scania's current 24-volt power supply system. The redundant power supply is supposed to power a control unit wich has sufficient functionality to stop the vehicle safely. Two different redundant battery systems have been designed and adapted for Scania's existing electrical power supply system. DC/DC converters are designed to regulate the voltage levels of the two different redundant battery systems. One battery system is designed as an inactive backup system and the other battery system is designed as an active backup system. The goal of the project has been to test and evaluate the differences between these systems. The focus has been on the big difference between the systems, which is the transition between primary and redundant power supply.