Offline UPS are the systems in which load is directly fed at the time of normal operations from the mains. As long as the load is concerned, power storage components including the inverters, batteries and chargers are offline and remain connected to their mains so that the battery remains fully charged and the power remains constant and uninterrupted. In case of failure or fluctuation of the mains, the inverter output directly switches. The Offline UPS allows higher efficiency because the charger does not remain on continuously. Further, these devices are cost efficient and easy to install.