Technical performance analysis of high-voltage battery-based photovoltaic water pumping systems

Energy efficiency in photovoltaic systems is especially important when batteries are part of the system. Performance optimization includes the selection of the best efficiency point for each stage of the system, and the inclusion of devices that reduce energy losses when some elements of the system are not operating. This paper proposes improving battery-based photovoltaic pumping systems by using high-voltage lithium batteries, combined with the inclusion of IoT switches and the operation of the pumping system at its most efficient operating point. Experimental results of a system working with different irradiance profiles are included for an analysis of the main working parameters. These parameters demonstrate how the inclusion of IoT switches improves system efficiency and provides extra energy that can be used to pump additional water or for other purposes. A comparison of the results obtained with the estimates made for direct pumping shows that the battery-based solution yields an average increase of 10.85 % on a sunny day (with 5.29 PSH) and 16.37 % on a cloudy day (with 2.88 PSH). Some water is pumped on days with less than 2 PSH, while direct pumping is unable to pump on those very cloudy days.