The electric industry has been experiencing an exponential growth of battery energy storage deployments; however, there is industry wide inconsistency with determining appropriate values for operations and maintenance (O&M) planning. This study attempts to provide a bottom up method of estimating O&M for battery energy storage systems with the ability to compare various maintenance strategies. This study outlines key areas of focus for energy storage systems as it pertains to O&M, various maintenance approaches, and what the benefits and trade-offs are for the different approaches. These findings are summarized within the report and are meant to serve as a guide for decision making. The various strategies and estimated costs are used as the basis for a prototype tool developed as apart of this research, that provides users the ability to evaluate the different strategies based on their unique assumptions and how those assumptions impact the capacity, energy, and costs over the life of the battery. The overall goal is to deliver a clear and concise understanding of potential O&M strategies for battery energy storage systems and the impact on costs over an asset’s life.