Adaptive State-of-Charge–Driven Energy Management with Rain-Responsive Irrigation for Solar-Powered Multicrop Hydroponics in Tropical Islands

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Chinese explanation / 中文解读

中文解读待补充：本站会优先为光伏效率、钙钛矿太阳能电池、储能技术、太阳能热利用、BIPV、并网技术等高价值论文补充中文说明。

Original abstract

This study addresses the need for resilient, off-grid food production on tropical islands by integrating renewable energy management with outdoor hydroponic cultivation. The objective of the research was to design and fieldvalidate an adaptive energy balance controller that coordinates energy availability and water management using real-time measurements of battery state of charge (SoC) and rainfall–runoff signals. The proposed system comprised a photovoltaic array, a battery energy storage unit, low-cost environmental and electrical sensors, and an embedded microcontroller executing a supervisory control policy. SoC was estimated from voltage and current measurements with signal conditioning to stabilize noisy data, enabling rain-aware irrigation prioritization during daylight hours and SoC-dependent duty cycling during nighttime operation. Using 5-minute averaged data, the SoC estimation achieved a mean absolute error of 1.207% and a root mean square error of 1.689%, corresponding to estimation accuracies of 98.79% and 98.31%, respectively. Field trials on a nutrient film technique hydroponic system in East Lombok, Indonesia, under sunny, cloudy, and rainy conditions demonstrated that SoC was maintained above a conservative safety margin, recovering during daylight periods and declining in a controlled manner overnight. Rainfall–runoff detection suspended irrigation for extended durations, with brief circulation intervals to maintain root oxygenation, thereby reducing water consumption and limiting nutrient dilution. Nighttime duty cycling aligned pump operation with available stored energy, avoiding deep discharge and supporting battery health. Time-series analysis confirmed autonomous responses without manual intervention.

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