Abstract: A photovoltaic panel for converting solar energy into electrical energy output having a voltage and a current and a load requiring a starting current which is higher than a minimum running current. The output of the photovoltaic panel is detected by a sensor and circuitry is responsive to the sensor for applying the output to the load in pulses at a frequency which varies inversely with the maximum available power from the panel.

Abstract: The present invention is a device for a solar heating system having a solar collector, a storage tank connected to the solar collector, a pump for circulating liquid from the tank to the solar collector, a supply of liquid at a temperature above freezing and a connection from the supply of liquid to the solar collector for replacing any liquid lost from said solar collector. The device comprises a sensor for sensing the temperature of liquid in the solar collector, and a valve for bleeding liquid from the solar collector when the sensed temperature falls below a predetermined minimum whereby cool liquid in the solar collector is automatically replaced by liquid at a temperature above freezing.

Abstract: The invention comprises a photovoltaic panel for converting solar energy into electric energy, a load and a capacitor connected to the photovoltaic panel for receiving current produced by the panel and storing the current to produce an output voltage which increases with the amount of stored current. A relay connects the photovoltaic panel and capacitor to the inductive load when the output voltage of the capacitor has reached a predetermined level which corresponds to an optimum operating voltage range of the photovoltaic panel.