If the flow sensor is installed and a power outage occurs, HUGO will remain in standby mode until it detects water flow. Once water flow is detected, HUGO will begin converting DC to AC, enabling your tankless water heater to power on. After you've finished using water and all water taps are closed, HUGO will cut power to the tankless water heater after a 5-minute delay to conserve battery life for future hot water use. With typical daily hot water usage of about one hour, the HUGOv2-L30 LiFEPO4 battery can provide sufficient power for 3 to 7 days, depending on your tankless water heater's specific energy consumption, and the HUGOv2-L50 will provide 70% more runtime compared to the L30.