Rancang Bangun Battery Management System Berbasis Internet of Things dengan Protokol Komunikasi MQTT pada Battery Energy Storage System di Pembangkit Listrik Tenaga Surya

Yuta Ilham Nugroho, Dr. Raden Sumiharto, S.Si., M.Kom.

2026 | Skripsi | ELEKTRONIKA DAN INSTRUMENTASI

Sistem Battery Energy Storage System (BESS) pada Pembangkit Listrik Tenaga Surya (PLTS) memerlukan pemantauan parameter baterai lithium-ion secara berkelanjutan, mencakup tegangan tiap sel, arus, State of charge (SoC), dan State of health (SoH). Battery Management System (BMS) konvensional yang masih bergantung pada pemantauan lokal tanpa konektivitas jarak jauh mengharuskan operator hadir secara fisik di lokasi, sehingga respons terhadap kondisi abnormal seperti ketidakseimbangan tegangan antar sel dan degradasi kapasitas menjadi terlambat. Penelitian ini merancang prototipe BMS berbasis IoT menggunakan ESP32 yang terintegrasi dengan IC LTC6804-2 melalui SPI untuk akuisisi tegangan sel, sensor arus ACS712-5A, serta mekanisme passive cell Balancing hybrid. Estimasi SoC dihitung dengan metode berbasis tegangan (pemetaan linier 2,80–4,20 V), sedangkan kapasitas terintegrasi BMS divalidasi terhadap multimeter untuk menilai akurasi rantai sensor arus pada estimasi SoH. Data dikirimkan ke broker HiveMQ Cloud via protokol MQTT dengan enkripsi TLS, lalu divisualisasikan pada dashboard web berbasis JavaScript murni (vanilla JS) yang di-hosting di Vercel tanpa server backend. Pengujian menunjukkan akurasi tegangan sel dengan error 7 mV pada SoC 85% yang meningkat hingga 92 mV pada SoC 40%, serta akurasi arus statis di bawah 3,5?ngan R² = 0,9961. Estimasi SoH dari kapasitas terintegrasi BMS menghasilkan deviasi sebesar +17,3% terhadap referensi. Proteksi cut-off terverifikasi dengan trigger overcurrent pada 1,643 A dalam satu siklus loop firmware, dan cell Balancing menghasilkan 14 event aktif dengan syarat logika terpenuhi 100%. Komunikasi MQTT mencapai reliabilitas 100% tanpa packet loss dengan latensi median 63 ms.

The Battery Energy Storage System (BESS) in Solar Power Plants (SPP) requires continuous monitoring of lithium-ion battery parameters, including per-cell voltage, current, State of charge (SoC), and State of health (SoH). Conventional Battery Management Systems (BMS) that rely on local monitoring without remote connectivity force operators to be physically present on-site, delaying response to abnormal conditions such as inter-cell voltage imbalance and capacity degradation. This research develops an IoT-based BMS prototype using an ESP32 microcontroller integrated with an LTC6804-2 IC via SPI for cell voltage acquisition, an ACS712-5A current sensor, and a hybrid passive cell Balancing mechanism. SoC is estimated using a voltage-based linear mapping (2.80–4,20 V), while the BMS-integrated capacity is validated against multimeter measurements to assess the current-sensing chain accuracy for SoH estimation. Data is transmitted to HiveMQ Cloud broker via MQTT protocol with TLS encryption, then visualized on a vanilla-JavaScript web dashboard hosted on Vercel without a backend server. Testing results show cell voltage accuracy with a mean error of 7 mV at SoC 85% increasing to 92 mV at SoC 40%, and static current accuracy below 3.5% with R² = 0.9961. SoH estimation from the BMS-integrated capacity  yielded a deviation of +17.3% relative to the reference. The cut-off protection was verified with an overcurrent trigger at 1,643 A within a single firmware loop cycle, and cell Balancing produced 14 active events with all firmware logic conditions met 100%. MQTT communication achieved 100% reliability with zero packet loss at a median latency of 63 ms.

Kata Kunci : Battery Management System, BMS, IoT, MQTT, SoC, SoH, passive balancing, ESP32, LTC6804-2