We develop a power supply that can repeatedly charge and discharge for a renewable energy by using the electric double layer capacitor (EDLC) and a photovoltaic module. We also fabricate the EDLC (charcoal EDLC) for the power supply, which is made of a charcoal and a water-based electrolyte. The charcoal EDLC has a high-safety performance due to the structure of incombustibility and the resistance to the invasion of the water. We fabricate an outdoor lighting system by using the charcoal EDLC and investigate the problems for the long-term operation. The outdoor light system is constructed with the charcoal EDLC (60 Wh), the photovoltaic module (60 W), the LED light device (6 W) and our original control circuit. The results of demonstration experiments show that the developed outdoor light system operates as a power supply for a LED light device in the nighttime in a high efficiency. It is confirmed that the system operates for a long time, but the results also show that there are problems such as incomplete charcoal EDLC sealing and electric resistance rise due to electric terminal corrosion from the test results for 2 years and 4 months after installation.
