Adaptive Energy Balance Control System via State of Charge (SOC) for a Sustainable Solar-Powered Outdoor-Hydroponics in Tropical Islands

Efficient energy management is essential for sustaining outdoor hydroponics systems powered by solar energy, particularly in tropical island environments where sunlight and rainfall vary throughout the day. To address this, a solar-powered hydroponics system was developed with an adaptive energy balance control strategy based on the State of Charge (SoC). The system requires reliable real-time monitoring and decision-making, achieved by integrating voltage, current (ACS712), light-dependent resistors (LDR), and flow sensors, along with an ESP32 microcontroller for data acquisition and control logic. The adaptive control method dynamically regulates power consumption by adjusting the water pump's operation in response to SoC levels, solar radiation, and rainfall. Experimental validation shows the system maintains the battery’s SoC above 55%, ensuring power availability while optimizing energy use. Pump operation is disabled during rainfall and minimized at night to prevent deep discharge, enhancing overall system stability. Daytime solar charging is complemented by controlled discharge during non-solar hours, improving energy sustainability. The results confirm the effectiveness of the proposed strategy in reducing unnecessary energy consumption, improving system reliability, and supporting continuous hydroponic cultivation under varying tropical conditions. ABSTRAK: Pengurusan tenaga yang cekap amat penting bagi memastikan kelestarian sistem hidroponik luar yang menggunakan tenaga solar, terutama di kawasan pulau tropika yang mempunyai corak cahaya matahari dan perubahan hujan sepanjang hari. Bagi memenuhi keperluan ini, satu sistem hidroponik berkuasa solar telah dibangunkan dengan strategi kawalan imbangan tenaga adaptif berasaskan Keadaan Cas (SoC). Sistem ini memerlukan pemantauan masa nyata dan keupayaan membuat keputusan terpercayai, dicapai melalui integrasi penderia voltan, arus (ACS712), LDR (Rintangan Peka Cahaya), dan aliran, serta mikropengawal ESP32 bagi pemerolehan data dan logik kawalan. Kaedah kawalan adaptif ini mengatur penggunaan tenaga secara dinamik dengan melaras operasi pam air berdasarkan tahap SoC, intensiti cahaya matahari, dan keadaan hujan. Dapatan kajian menunjukkan sistem ini mampu mengekalkan SoC bateri melebihi 55%, sekaligus memastikan bekalan kuasa yang stabil sambil mengoptimum penggunaan tenaga. Operasi pam dihentikan semasa hujan dan dikurangkan pada waktu malam bagi mengelakkan nyahcas bateri berlebihan, seterusnya meningkatkan kestabilan sistem. Pengecasan bateri pada waktu siang dilengkapi dengan penyahcasan terkawal semasa tanpa cahaya matahari, sekaligus memperkukuh kemampanan tenaga. Dapatan kajian membuktikan bahawa strategi kawalan ini berkesan dalam mengurangkan penggunaan tenaga tidak diperlukan, meningkatkan kebolehpercayaan sistem, dan menyokong penanaman hidroponik berterusan dalam persekitaran tropika yang dinamik.