International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 12 Issue: 11 | Nov 2025
p-ISSN: 2395-0072
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“Solar UPS Project” 1Prof. Rohan Shinde, 2Sakshi Mule,3Pradnya Galbale,4Pranjali Jadhav,5Revan Pathare 1Assistant Professor, 2,3,4,5UG scholar, Electronics & Communication Engineering Department,
School of Engineering & Sciences, MIT Art, Design & Technology University, Pune, India -------------------------------------------------------------------------***-----------------------------------------------------------------------hybrid solar UPS topologies [12–14]; however, most Abstract - This study presents the design, prototyping, and
reported systems either (i) employ expensive lithium-ion batteries, (ii) lack seamless transfer capability during grid failure, (iii) omit maximum power point tracking (MPPT) leading to suboptimal PV utilization, or (iv) have not been validated under realistic residential/small-office load profiles. This paper presents the design, prototyping, and comprehensive experimental evaluation of a low-cost solar-integrated UPS system tailored for domestic and small-commercial applications in regions with unreliable grid supply. The proposed system combines a PV array, MPPT charge controller, deep-cycle battery bank, pure sine-wave inverter, and a priority-based automatic transfer mechanism to achieve seamless switching with near-zero transition time while significantly reducing grid energy consumption. Through detailed component selection, accurate sizing methodology, and extensive testing under simulated and real-world outage scenarios, this work demonstrates a practical, affordable (< $350), and environmentally friendly alternative to conventional UPS solutions, capable of delivering uninterrupted power with >85 % round-trip efficiency and >60 % reduction in annual grid dependence.
experimental validation of a low-cost solar-integrated uninterruptible power supply (UPS) for residential and small-office applications in unreliable grid regions. The system combines a 100 Wp PV panel, 20 A MPPT charge controller, 12 V 100 Ah deep-cycle battery, and 600 VA pure sine-wave inverter with a relay-based automatic transfer circuit achieving 4–7 ms seamless switching. Testing under real and simulated outage conditions demonstrated roundtrip efficiency >86 %, backup duration of 3.5–7 hours at 150–400 W loads, and >68 % reduction in annual grid dependence. The complete prototype was realized for under US $350, offering a payback period below 2.1 years compared to diesel-backed solutions. Results confirm the technical viability and economic feasibility of solar UPS systems as sustainable, reliable alternatives to conventional grid-only or generator-dependent backup power.
Keywords: Solar UPS, PV panel, Charge controller, Battery bank, Inverter, Renewable energy, Power backup, Grid failure, Energy storage. 1.1 INTRODUCTION Uninterruptible power supply (UPS) systems are essential for ensuring continuous electricity delivery to critical loads during grid outages or disturbances [1,2]. By instantaneously switching to stored energy, conventional UPS units protect sensitive equipment—such as medical devices, servers, telecommunication infrastructure, and industrial controllers—from voltage sags, surges, and complete blackouts, thereby preventing data loss, hardware damage, and operational downtime [3–5]. Despite their widespread adoption, commercially available UPS systems predominantly rely on valveregulated lead-acid (VRLA) batteries charged exclusively from the grid. This design results in recurrent charging costs, increased dependence on often-unreliable or carbon-intensive electricity grids, and a larger environmental footprint [6,7]. In developing regions and areas with frequent load-shedding, users frequently pair UPS units with fossil-fuel generators, further exacerbating operational expenses and greenhouse gas emissions [8]. The integration of renewable energy sources, particularly solar photovoltaics (PV), into UPS architectures, offers a promising pathway toward sustainable and cost-effective backup power [9–11]. Several studies have explored
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2. OBJECTIVES OF THE RESEARCH The primary objectives of this study are as follows: 1.
To design and implement a solar-integrated uninterruptible power supply (UPS) system capable of delivering seamless, uninterrupted power to critical residential and small-office loads during grid outages. 2. To harness renewable solar energy as the primary source for battery charging and backup power provision, thereby reducing dependence on grid electricity and fossil-fuel-based generators. 3. To enhance overall system efficiency and reliability through the adoption of maximum power point tracking (MPPT) charge control, high-efficiency power conversion, and robust overcharge/deep-dischargeprotection echanisms. 4. To achieve near-zero transition time when switching among grid, photovoltaic, and battery sources using a priority-based automatic transfer circuit, ensuring no disruption to sensitive electronic equipment.
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