Optimization of System Efficiency and Energy Management in a Low-Voltage DC Solar Generator

International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 Original Article ©2025 RS Publicaon, rspublica[email protected] 192 Optimization of System Efficiency and Energy Management in a Low-Voltage DC Solar Generator Uduak Etim Udoka and Okon Nsa Ufot Department of Computer Engineering Technology, Akwa Ibom State Polytechnic, Ikot Osurua, Akwa Ibom, Nigeria PMB 1200 ARTICLE INFO  ABSTRACT Paper ID: Paper ID: IJCA-68DC0BF2B3E83 Received: 2025-09-02 Published: 2025-10-05 DOI: https://dx.doi.org /10.5281/zenodo.17 330545 Page No: 192-202 The growing demand for sustainable and decentralized energy solutions has made low-voltage DC solar generators critical for rural electrification, backup systems, and small-scale applications. This study focuses on the optimization of system efficiency and energy management in a 12 V low-voltage DC solar generator designed and tested under real operating conditions in Ikot Ekpene, Akwa Ibom State, Nigeria. The system integrates photovoltaic modules, an MPPT-based charge controller, lithium-ion storage, and DC-compatible loads, with performance monitored under varying irradiance. Results reveal that while the PV array is rated at 370 W, realworld derating and conversion losses reduce usable AC power to approximately 253 W, highlighting the gap between nominal and effective capacity. Comparative analysis of series and parallel array configurations shows that system design choices directly influence wiring losses, controller limits, and overall reliability. Battery storage proved essential in bridging the gap between peak demand and intermittent solar generation, with runtime analysis confirming its critical role in sustaining system loads. Furthermore, PV power gain analysis demonstrated that maximum energy harvest occurs at midday, though efficiency declines slightly at high irradiance due to thermal effects. The findings underscore the importance of intelligent energy management strategies such as load prioritization, optimized battery cycling, and predictive control in maximizing usable output. This study concludes that with proper system optimization, low-voltage DC solar generators can provide reliable, sustainable, and cost-effective energy for smallto medium-scale applications, advancing Nigeria’s renewable energy transition and improving energy access in underserved regions. Keywords: Low-voltage DC solar generator, photovoltaic systems, energy management, system optimization, MPPT, battery storage 1. Introduction The global shift towards renewable energy has placed solar power at the centre of sustainable energy generation strategies. Rising concerns over climate change, depletion of fossil fuel resources, and the pressing need for clean, decentralized energy solutions have accelerated Internaonal Journal of Advanced Scienfic and Technical Research Available online on hp://www.rspublicaon.com/ijst/index.html ISSN 2249-9954 Cite This Paper : Uduak Em Udoka and Okon Nsa Ufot (2025). "Opmizaon of System Efficiency and Energy Management in a Low-Voltage DC Solar Generator". INTERNATIONAL JOURNAL OF ADVANCED SCIENTIFIC AND TECHNICAL RESEARCH (IJASTR), vol. 15, no. 5, 2025, pp. 192-202. DOI: h7ps://dx.doi.org/10.5281/zenodo.17330545 International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 Original Article ©2025 RS Publicaon, rspublica[email protected] 193 investments in solar technologies. While large-scale photovoltaic (PV) farms dominate discussions on solar energy, small-scale and low-voltage DC solar generators are equally significant (Hassan et al.,2023; Soudagar et al.,2024; Mohammadi et al.,2020; Algburi, et al.,2024. They provide direct energy access to rural communities, support portable energy applications, and serve as reliable backup systems. However, their effectiveness depends not only on the capacity of the PV panels but also on the efficiency of the entire system and the management of generated energy. Optimizing system efficiency and improving energy management are therefore central to unlocking the full potential of low-voltage DC solar generators (Nwagu et al.,2025; Juanpera et al.,2021; Bugaje, 2023). Ali et al. (2025) in their investigative studies observed that solar energy conversion efficiency has long been a challenge while advances in PV cell technology continue to raise conversion rates. The overall system often suffers from losses in power conditioning, storage, and load management. For low-voltage systems, these losses can be proportionally larger, making optimization more critical. Inefficiencies in charge controllers, inverters, and energy storage units reduce the usable power available, often discouraging users. As a result, most research has shifted from focusing solely on panel efficiency to a holistic system-level approach. This includes optimizing the interaction between PV modules, energy storage units such as batteries, and load demand through advanced energy management strategies as illustrated in Figure 1 (Al-Ali et al.,2025; Ogundipe et al.,2024). Figure 1: Solar Power Generation The concept of energy management in DC solar generators is fundamentally about balance. Solar generation is inherently intermittent, depending on solar irradiance, temperature, and weather conditions. On the other hand, user demand is irregular, varying by time of day and the nature of appliances connected. Without intelligent management, this mismatch leads to either wasted energy during peak generation or shortages during periods of high demand. Energy management strategies, therefore, ensure that supply and demand are harmonized through techniques such as maximum power point tracking (MPPT), smart charging and discharging cycles of batteries, load prioritization, and predictive control algorithms. In lowvoltage systems, where power margins are slim, such optimization directly improves reliability and user satisfaction (Folorunso et al.,2025; Baraneedharan et al.,2024). The efficiency of low-voltage DC solar generators also depends on reducing conversion losses. Unlike AC-based systems, DC systems can operate with fewer conversion stages. For instance, International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 Original Article ©2025 RS Publicaon, rspublica[email protected] 194 loads such as LED lighting, laptops, and certain communication devices natively run on DC. Eliminating unnecessary DC-AC or AC-DC conversions not only reduces losses but also cuts costs. However, even within DC systems, challenges exist. Voltage fluctuations, thermal losses, and improper load matching often reduce usable efficiency. Optimization efforts, therefore, extend beyond hardware improvements to include intelligent control strategies that stabilize voltage, balance currents, and regulate power distribution (Zdiri et al.,2023; Hassan et al.,2024; Katar & Uzunoglu, 2021). A critical component in these systems is the charge controller. It regulates the flow of energy from the solar panels to the battery and the load. Traditional controllers rely on simple on-off mechanisms that often fail to extract the maximum energy available from the PV modules. Modern controllers, however, incorporate MPPT algorithms, which continuously adjust the operating point of the solar array to achieve maximum efficiency. In low-voltage generators, MPPT is particularly impactful because the available margin between optimal and sub-optimal performance is narrow. A well-designed MPPT system can improve energy harvest by 20 to 30 percent, directly enhancing system reliability (Faizal et al.,2022; Perdana et al.,2021). Energy storage plays an equally central role in system optimization. Batteries, typically leadacid or lithium-ion, are the backbone of off-grid solar systems. However, they are also a source of inefficiency due to charging losses, self-discharge, and cycle degradation. Optimizing battery management involves not only efficient charging algorithms but also predictive models that extend battery life by avoiding deep discharges and overcharging. In addition, hybrid storage systems that integrate supercapacitors for transient loads are gaining attention as they improve overall system responsiveness while protecting the main battery from stress. For lowvoltage systems, careful energy storage design ensures stable output and maximizes the lifespan of costly battery components (Hasan et al.,2025; Mageto et al., 2021; Hamdan et al.,2024). Beyond technical aspects, system optimization also involves user behaviour and awareness. Many small-scale solar systems underperform not because of hardware limitations but due to misuse or lack of maintenance. Educating users on energy-efficient practices, such as using DC-compatible appliances, scheduling high-load tasks during peak sunlight hours, and maintaining batteries properly, complements technical optimization. Energy management thus becomes both a technological and social challenge, requiring alignment between system design and user engagement (Soomar et al.,2022; Kazem et al.,2022). From a broader perspective, the optimization of low-voltage DC solar generators has economic and social implications. By maximizing energy efficiency, system costs per unit of usable electricity are reduced, making solar solutions more affordable for low-income communities. Enhanced reliability also increases user trust and adoption, which supports the growth of decentralized renewable energy markets (Effah et al.,2025; Nagaraja et al.,2025). Furthermore, optimized systems reduce the dependence on diesel generators, lowering emissions and contributing to climate change mitigation. For rural electrification projects, efficient and intelligently managed solar generators represent a pathway to sustainable development by providing reliable power for households, schools, health centres, and micro-enterprises (Panagoda et al.,2025; Nagaraja et al.,2025). In conclusion, the optimization of system efficiency and energy management in low-voltage DC solar generators is not a singular task but a multi-dimensional challenge. It encompasses improvements in PV harvesting, storage management, load prioritization, thermal regulation, International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 Original Article ©2025 RS Publicaon, rspublica[email protected] 195 and user engagement. At its core, it is about making the best use of limited solar resources to deliver reliable, sustainable, and affordable energy. As the demand for decentralized renewable systems grows, especially in underserved regions, the lessons learned from optimizing lowvoltage solar generators will play a central role in shaping future energy landscapes. This study is therefore dedicated to advancing the understanding of how integrated optimization strategies can transform simple solar generators into robust energy solutions capable of meeting modern demands efficiently. 2. Materials and method 2.1 System Components The experimental setup of the study consists of a low-voltage DC solar generator which is designed to operate at 12 V. The materials are well illustrated in Table 1. Table 1: Material Component for the Study S/N Material Specification 1. Photovoltaic (PV) Modules 2 x 185W configured to ensure stable low-voltage output. 2 Charge Controller 30A DC-DC converter–based Maximum Power Point Tracking (MPPT) 3 Battery 12.6V, 110 Ah lithium - ion battery 3 Inverter Pure sine wave DC – AC inverter with 12 VDC, 300 W 4 Load Devices DC - compatible appliances 5 Monitoring Instruments Digital multi - meters to monitor voltage fluctuations 2.2 Experimental Setup The PV modules were installed outdoors under standard test conditions and connected to the charge controller. The battery was linked downstream to store energy, while loads were connected via a regulated DC bus. The MPPT controller ensured that the PV modules operated close to their maximum power point despite fluctuations in irradiance and temperature. Data acquisition systems continuously recorded voltage, current, power, and temperature at 1minute intervals. 2.3 Data Analysis and Optimization Approach The study adopted a two-stage methodology. The first one was system efficiency assessment which the baseline efficiency was determined by measuring the ratio of usable output power to incident solar power over varying irradiance levels. Conversion and storage losses were quantified by comparing input and output at each stage (PV, controller, battery, and load) as shown in Figure 2. Another approach was the energy management strategies. This involves load prioritization algorithms were implemented through the controller to ensure critical loads received power first. Battery charging and discharging cycles were optimized by applying state-of-charge (SOC) thresholds. Collected data were analyzed to evaluate system performance under different operating conditions. The Key metrics included overall system efficiency, battery round-trip efficiency, load satisfaction rate, and energy loss distribution. International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 Original Article ©2025 RS Publicaon, rspublica[email protected] 196 Results were compared against simulated models to assess consistency and validate the optimization framework. 2.4 System Design Figure 2: Block Diagram of the Solar DC generator 3. Result and Discussion 3.1 PV System Assumptions and Power Flow The design for the study has two identical photovoltaic (PV) panels, each rated at 185 W. Collectively, the array produces 370 W under standard test conditions. After accounting for real-world derating factors such as soiling, temperature, wiring losses, and panel mismatch, the usable power falls to 296 W. Subsequent conversion losses through the maximum power point tracking (MPPT) controller and inverter reduce the final available alternating current (AC) output to approximately 253 W. This table illustrates a crucial lesson in solar system design: the nameplate capacity of PV panels does not equate to usable output. Each stage in the system introduces efficiency losses, and in practical deployment, only about 68% of the nominal capacity remains as usable AC power. 3.2 Series vs Parallel Array Configuration of the System A comparison of series and parallel connections as shown in Figure 3 shows that while the overall power output remains constant when an MPPT controller is used, the electrical characteristics differ significantly. A series connection doubles the voltage (36 V) while maintaining current at about 10.3 A. In contrast, a parallel arrangement keeps the voltage at 18 V but doubles the current to roughly 20.6 A. The choice between series and parallel is not trivial. Series configurations reduce current and thus lower wiring losses, making them more efficient for transmission. Parallel connections, however, require heavier cabling and higher current ratings but may be necessary in systems constrained by controller voltage limits. The International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 Original Article ©2025 RS Publicaon, rspublica[email protected] 197 key takeaway is that system designers should prefer series connections, when possible, to optimize efficiency, provided that the controller can handle the higher input voltage. Figure 3: Series vs Parallel Array Configuration 3.3 Inverter Capability and Battery Support The inverter is rated at 350 W continuous output. To deliver this at 90% efficiency, it requires 389 W of direct current (DC) input, which corresponds to a battery discharge current of about 31 A at 12.6 V. Since the PV array can only sustain 253 W under optimal sunlight, the inverter cannot operate at its full rating from solar power alone. The shortfall must be supplemented by the battery. This finding highlights a limitation of the system: while the inverter is technically oversized for the solar input, it depends heavily on the battery for peak performance. Designers must therefore ensure that the battery bank, cables, and fuses are rated to handle discharge currents above 31 A safely. On battery runtime analysis, A runtime table ( see Table 2) evaluates system performance with two battery sizes: 50 Ah and 100 Ah at 12.6 V. At 80% depth of discharge (DoD), the 50 Ah battery provides about 504 Wh of usable energy, while the 100 Ah battery provides roughly 1,008 Wh. Under PV-limited operation (253 W), runtimes are 2.0 and 4.0 hours, respectively. At full inverter load (350 W), runtimes drop to 1.3 and 2.6 hours. This analysis reinforces the critical role of battery storage as shown in Table 2. Table 2: Inverter capability and battery-only operation Metric Value Inverter rated continuous AC output 350 W DC input power required for 350 W AC @ 90% eff 350 / 0.90 = 388.89 W Battery DC current required at 12.6 V for full inverter output 388.89 / 12.6 = 30.89 A Without adequate capacity, the system cannot sustain loads beyond a few hours. Larger batteries not only extend runtime but also buffer intermittent solar input, improving overall reliability. 0 50 100 150 200 250 300 350 400 Array Vmp Array Imp Nominal PV power PV power after derate (80%) Power after controller (95%) Charging current into 12.6 V battery AC output available (after inverter, 90%) Parallel connection (2 × 185 W) Series connection (2 × 185 W) International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 Original Article ©2025 RS Publicaon, rspublica[email protected] 198 3.4 Daily Load Audit The load audit as shown in Table 3 provides a detailed estimate of the daily energy requirements of the selected appliances and accessories intended for use within the system. The analysis considered three main categories of loads: trainers’ accessories, trainers operating at 5 V and 2 A, and LED bulbs of 15 W each. The energy demand for each item was determined by multiplying the rated power of the appliance, the quantity in use, and the number of hours of operation per day. From the results, the trainers’ accessories contribute the least to the daily load profile with an estimated 20 Wh/day. This value arises from a single accessory rated at 10 W and operated for only two hours daily resulting in 720 Wh/day total energy. Although the consumption is low, it is important to account for such auxiliary devices because they add to the cumulative system demand. the load audit reveals that the energy demand is relatively modest but concentrated in specific categories, particularly the trainers. Such an analysis emphasizes the importance of both efficient load management and accurate system design. By understanding the relative contribution of each device, as engineers can prioritize energysaving strategies, ensure adequate capacity for critical loads, and avoid oversizing or under sizing the solar energy system. Table 3: Load Audit Table (Per Day) Item Qty Power (W) each Hours/day Subtotal Energy (Wh/day) Trainers Accessories 1 10 2 10 × 2 = 20 Wh Trainers (5V, 2A) 10 10 4 10 × 10 × 4 = 400 Wh LED bulbs (15 W) 5 15 4 5 × 15 × 4 = 300 Wh Daily Total 720 Wh/day 3.5 Maximum Power Gain by the PV Panel Figures 4 and 5 represents the analysis that focuses on the performance of photovoltaic (PV) systems under the solar irradiance conditions of Ikot Ekpene, Akwa Ibom State, Nigeria. The figures illustrate the relationship between solar intensity and PV output, providing insight into the system’s efficiency, reliability, and potential for renewable energy deployment in the region. Figure 4 shows the power gain of the PV system at peak solar irradiance. The results reveal that maximum power generation coincides with midday periods when solar radiation is strongest. This observation aligns with the theoretical performance of PV cells, which convert solar energy more efficiently under high irradiance. However, efficiency drops slightly beyond certain irradiance thresholds due to heat build-up, which increases the internal resistance of the cells. This implies that while the location benefits from high solar availability, effective thermal management strategies, such as passive cooling or material optimization, are necessary to sustain long-term efficiency. Figure 5 illustrates PV power and energy output at different time intervals throughout the day. The graph confirms a direct correlation between irradiance levels and output, with morning and evening periods showing reduced production compared to midday peaks. The cumulative energy output indicates that the system is capable of producing sufficient electricity for smallto medium-scale applications if properly sized. Importantly, the analysis suggests that incorporating energy storage (batteries) is vital to balance supply during periods of low irradiance, ensuring reliability for households and businesses. International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 Original Article ©2025 RS Publicaon, rspublica[email protected] 199 The findings highlight the strong potential of PV systems in Akwa Ibom State, where abundant solar resources can be harnessed to mitigate electricity shortages. With proper integration of storage systems and efficient grid management, PV technology could significantly reduce dependence on fossil fuels and enhance energy security. Furthermore, scaling up PV deployment aligns with Nigeria’s national energy transition agenda, offering socio-economic benefits such as job creation, reduced carbon emissions, and cost savings for rural and urban consumers alike. Figure 4 : Power Gain by the PV at maximum daily solar irradiance at Ikot Ekpene Akwa Ibom State Nigeria Figure 5: Plot of PV power and energy output a different time interval 0 200 400 600 800 1000 1200 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 24:00:00 Output Values (W) Time (Hours) Irradiance G (W/m²) Ideal PV power (W) = 370·G/1000 0 50 100 150 200 250 300 350 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 24:00:00 Output Values (W) Time (Hours) PV power (W) × 0.84 Energy Output/Hour International Journal of Advanced Scientific and Technical Research ISSN 2249-9954 Available online on http://www.rspublication.com/ijst/index.html volume 15, No. 5, 2025 Original Article ©2025 RS Publicaon, rspublica[email protected] 200 4. Conclusion The study comprehensively evaluated the performance and optimization of a low-voltage DC solar generator, revealing that system efficiency is strongly influenced by PV array configuration, storage capacity, inverter sizing, and energy management practices. Despite being rated at 370 W, the PV array yielded only about 68% of its nominal capacity as usable output, underscoring the importance of accounting for real-world derating factors and conversion losses in design. The comparison of series and parallel configurations confirmed that design decisions must balance voltage stability, current handling, and controller compatibility. Battery storage emerged as a central component, not only for extending runtime but also for stabilizing supply during fluctuations in irradiance. The analysis of daily load requirements further demonstrated the importance of precise auditing and prioritization in preventing oversizing or undersizing, ensuring that critical loads receive consistent supply. Additionally, the PV power gain and energy output trends at Ikot Ekpene highlight the region’s strong solar potential, with midday peaks providing substantial energy that can be harnessed for smallto medium-scale applications. However, efficiency drops during extreme irradiance stress the need for thermal regulation and optimized material design. Overall, the study concludes that intelligent integration of MPPT control, optimized storage, and load prioritization strategies can significantly improve the efficiency and reliability of lowvoltage DC solar systems. For Nigeria and similar regions facing power accessibility challenges, such systems present a viable pathway toward decentralized renewable energy deployment. They offer socio-economic benefits including enhanced energy security, reduced reliance on fossil fuels, and greater affordability for rural and peri-urban communities. Future research should extend the analysis to seasonal variations, advanced storage technologies, and AI-driven predictive management to further strengthen system performance and sustainability. References Al-Ali, S., Olabi, A. G., & Mahmoud, M. (2025). A review of solar photovoltaic technologies: developments, challenges, and future perspectives. Energy Conversion and Management: X, 101057. Algburi, S., Rendal, E., Jaber, Z. K., Fakhruldeen, H. F., Amjad, A., Sapaev, I. B., ... & Barakat, M. (2024). Evaluating the viability and potential of hybrid solar-wind renewable energy systems in relation to geographical and environmental factors. Results in Engineering, 103473. Ali, A. O., Elgohr, A. T., El-Mahdy, M. H., Zohir, H. M., Emam, A. Z., Mostafa, M. G., ... & Elhadidy, M. S. (2025). 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