A true bidirectional buck-boost approach for DC power backup applications provides utmost efficiency and improves overall system reliability. This approach is also ideal for optimizing battery health as the battery charge and discharge levels can be programmed as needed by the battery chemistry and according to the current health of the battery. This paper describes how a fully hardwired standalone backup system can be designed at a lower cost using the Renesas ISL81601 controller family. This approach reduces the cost by improving battery utilization and avoiding complicated current sensing and charging circuits.