Energy consumption by solar-powered watercraft at various speed settings

Abstract

Since the world's energy resources decrease, it is necessary to seek for opportunities to use renewable energy sources. One of the renewable sources is solar energy. During the last decade, solar energy was used by stationary installations for electricity generation, yet the use of solar energy by mobile installations is limited due to the size of solar photovoltaic panels. Modern vehicles typically use low-power solar panels to charge their batteries and power low-power electric devices. The present research used a plastic hull boat equipped with a standard electric motor Minn Kota Endura 30 and a 330W 36 V photovoltaic panel. Two experiments were conducted on the boat. During the pilot experiment, a distance of 41.5 km was covered by the boat equipped with a 5 Ah battery and a solar panel in 8.5 hours. The experiment was conducted on the Lielupe River upstream and downstream, seeking to reach the highest speed at different solar intensities in the month of August. The second experiment was conducted in September on a circular route in standing water, operating the boat at 5 different speed settings with average motor current consumption ranging from 7.3 to 21.86 A. The experiment identified the battery's charging and discharging current and voltage, and the motor's current and voltage at all the speed settings. The experiments showed that on a sunny day in the conditions in Latvia, the boat equipped with a stationary 330W solar photovoltaic panel can reach a maximum speed of up to 6 kmh -1 without using the battery. The efficiency of the solar panel was significantly affected by the direction of the boat's movement, which affected the angle of solar radiation and therefore the efficiency of the solar panel. To improve the efficiency of the solar panel, it is necessary to design a solar panel angle adjustment device that should be controlled automatically. Such a device is planned to be developed at the next stages of the research.