An apparatus comprising: an energy harvesting component; an energy storage component for receiving energy from the energy harvesting component and storing the received energy; and a controller for managing delivery of energy harvested by the energy harvesting component to a powered device, wherein the controller is configured to at least: when in a power-off state, automatically switch to a power-on state when the stored energy reaches a predetermined level; determine a previous power-off state of the controller before the controller entered the power-on state; in the event that the previous state was a dead mode state: determine energy level and harvested energy amount information from the energy storage element, determine power consumption and start a clock; in the event that the previous state was a deep sleep mode state: determine energy level and harvested energy amount information from the energy storage element, determine power consumption and read the clock to determine a duration of inactivity; activate the powered device (208, 210); and upon detecting that insufficient energy is available to continue powering a powered device, shut down the powered device, store power-off status information, and enter a power-off state. an energy harvesting component; an energy storage component for receiving energy from the energy harvesting component and storing the received energy; and a controller for managing delivery of energy harvested by the energy harvesting component to a powered device, wherein the controller is configured to at least: when in a power-off state, automatically switch to a power-on state when the stored energy reaches a predetermined level; determine a previous power-off state of the controller before the controller entered the power-on state; in the event that the previous state was a dead mode state: determine energy level and harvested energy amount information from the energy storage element, determine power consumption and start a clock; in the event that the previous state was a deep sleep mode state: determine energy level and harvested energy amount information from the energy storage element, determine power consumption and read the clock to determine a duration of inactivity; activate the powered device (208, 210); and upon detecting that insufficient energy is available to continue powering a powered device, shut down the powered device, store power-off status information, and enter a power-off state. when in a power-off state, automatically switch to a power-on state when the stored energy reaches a predetermined level; determine a previous power-off state of the controller before the controller entered the power-on state; in the event that the previous state was a dead mode state: determine energy level and harvested energy amount information from the energy storage element, determine power consumption and start a clock; in the event that the previous state was a deep sleep mode state: determine energy level and harvested energy amount information from the energy storage element, determine power consumption and read the clock to determine a duration of inactivity; activate the powered device (208, 210); and upon detecting that insufficient energy is available to continue powering a powered device, shut down the powered device, store power-off status information, and enter a power-off state.