Abstract: A power storage system includes: a power generation element that performs environmental power generation; a storage battery that is supplied with power generated by the power generation element; a DC/DC converter that converts an output voltage from the power generation element into a predetermined voltage; a first switch unit that switches whether directly supply the output voltage from the power generation element to the storage battery or to supply thereto via the DC/DC converter; and a first changeover unit that compares a voltage of the storage battery with a first threshold voltage, and controls the first switch unit according to a comparison result, in a case where a voltage of the voltage or higher of the storage battery bringing the DC/DC converter into a main boost mode is the first threshold voltage.

Abstract: A power storage system includes: a first storage battery that is configured to be supplied with power generated by a power generation element performing environmental power generation and to supply power to an external load apparatus; a second storage battery that is configured to have a capacity larger than a capacity of the first storage battery, and to supply power to the external load apparatus; a first switch unit that performs switching between an electrical connection state and disconnection state between the first storage battery and the second storage battery; and a first changeover unit that compares a voltage of the first storage battery with a first threshold voltage which is equal to or higher than a voltage causing the external load apparatus to be operated, and controls the first switch unit according to a comparison result.

Abstract: A sensor node includes a power generator, a power storage, a transmitter having an environment sensor, a transmission controller, and a transmission unit, a first switcher provided between the transmission controller and the power storage, and a second switcher provided between the transmission unit and the power storage. In a case where the storage capacity of the power storage decreases to a first threshold or less and then the storage capacity increases, when the storage capacity reaches the first threshold, the first switcher is brought into an on-state and the first switcher supplies electric power to the transmission controller. When the storage capacity reaches a second threshold higher than the first threshold, the second switcher is brought into an on-state and the second switcher supplies electric power to the transmission unit.

Abstract: A sensor node includes a power generator, a power storage, a transmitter having an environment sensor, a transmission controller, and a transmission unit, a first switcher provided between the transmission controller and the power storage, and a second switcher provided between the transmission unit and the power storage. In a case where the storage capacity of the power storage decreases to a first threshold or less and then the storage capacity increases, when the storage capacity reaches the first threshold, the first switcher is brought into an on-state and the first switcher supplies electric power to the transmission controller. When the storage capacity reaches a second threshold higher than the first threshold, the second switcher is brought into an on-state and the second switcher supplies electric power to the transmission unit.

Abstract: A power storage system includes: a power generation element that performs environmental power generation; a storage battery that is supplied with power generated by the power generation element; a DC/DC converter that converts an output voltage from the power generation element into a predetermined voltage; a first switch unit that switches whether directly supply the output voltage from the power generation element to the storage battery or to supply thereto via the DC/DC converter; and a first changeover unit that compares a voltage of the storage battery with a first threshold voltage, and controls the first switch unit according to a comparison result, in a case where a voltage of the voltage or higher of the storage battery bringing the DC/DC converter into a main boost mode is the first threshold voltage.

Abstract: A power storage system includes: a first storage battery that is configured to be supplied with power generated by a power generation element performing environmental power generation and to supply power to an external load apparatus; a second storage battery that is configured to have a capacity larger than a capacity of the first storage battery, and to supply power to the external load apparatus; a first switch unit that performs switching between an electrical connection state and disconnection state between the first storage battery and the second storage battery; and a first changeover unit that compares a voltage of the first storage battery with a first threshold voltage which is equal to or higher than a voltage causing the external load apparatus to be operated, and controls the first switch unit according to a comparison result.