The document provides detailed guidance on battery handling, maintenance, and testing for a power plant setting. It outlines the types of batteries, their applications, selection criteria, charging and discharging processes, as well as periodic maintenance schedules. Additionally, it addresses. by an agency of the U. Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness, of any information, apparatus, product, or. The Industrial and Commercial (C&I) Energy Storage: Construction, Commissioning, and O&M Guide provides a detailed overview of the processes involved in building, commissioning, and maintaining energy storage systems for industrial and commercial applications. Over the last decade, the installed base of BESSs has grown considerably, following an increasing trend in the number of BESS failure. In this in-depth guide, we will delve into the concepts of batteries in series and parallel at the same time, how to connect them, the differences between these arrangements, the advantages, and disadvantages, their application in energy storage, precautions, design considerations, optimization.