Portable solar panel efficiency measurement system
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Solar panel plays a major role in the renewable energy sector. Unfortunately substandard and unspecified solar panels are seen now a days in the market of many countries. Furthermore, solar panel testing equipment is not available everywhere and is a costly device. So, to fulfill customer rights and to know the efficiency of the solar panels, a simple portable solar panel efficiency measurement system has been designed and developed. The system includes a single Ardunio Uno, a voltage sensor, a current sensor (ACS712), a multi meter and a lux meter. The measurement has been taken under real sun conditions. The system determines maximum voltage (Vmax), maximum current (Imax), maximum power (Pm), fill factor (FF) and efficiency (η) of the solar panel. The system reveals that the efficiency of a 10 W, 8 W and 0.65 W silicon solar panel are 9.65%, 8.59% and 8.4% respectively.
KeywordsEfficiency Ardunio Lux meter Solar panel
In 2014, approximately 1.19 billion people lived without electricity. Furthermore, in Asia, countries like Pakistan, Indonesia and Bangladesh respectively has approximately 51, 41 and 61 million people living without electricity access . The demand for electricity still remains today and it is increasing twice as fast as overall energy use . To combat this electricity crisis and to provide electricity to electricity deprived people, off-grid solar energy is playing a crucial role. Off-grid solar energy, in particular solar home systems has been one of the fastest growing industries in providing energy access . As of 2016, more than 6 million Solar Home Systems (SHSs) are operational worldwide, with 25 million people benefiting from them . Regarding SHSs, Bangladesh has the largest market worldwide with more than 4.5 million units installed . The key element of a SHS is one or more PV modules and 98% of the installed solar panels used for SHS program in Bangladesh are imported from abroad [6, 7]. Currently there are still a vast demand of solar panels in Bangladesh. Unfortunately, it is seen in the local market that some of the imported solar panels are unspecified and substandard . In addition, substandard solar panels are also seen in the market of many countries like India, USA and Malawi [9, 10, 11]. As there is no standard testing institution to monitor the quality of solar panels in Bangladesh, different size and power PV modules has flooded the market of Bangladesh. Solar panel testing is only possible in Bangladesh Council of Scientific and Industrial Research (BCSIR), Dhaka and is very difficult for rural area people to come to the Dhaka City with the solar panels for testing. Moreover, in BCSIR solar panel testing takes about 10,000–15,000 BDT per panel which is a lot of money for common people. In addition, various companies like Oriel Instruments, Solar Tester, Abet Technologies, Nvis Technologies Pvt. Ltd sell different commercial solar panel efficiency measurement system. Even though these commercial available systems are very accurate but they are very costly. Thus it is difficult to provide this costly equipment to different areas for testing in the under developed countries. Therefore, problems like substandard solar panels, few testing facilities and costly panel testing procedure in many underdeveloped countries are the main reasons to design and develop a simple low cost portable solar panel efficiency measurement system. There are simulation based works to find out the solar cell parameters, as well as solar radiation measurement and onsite PV plant monitoring systems [12, 13, 14, 15, 16]. However, few reports in literature have been found for onsite unspecified solar panel testing equipment. So recently the researches have been concentrating on developing a simple, low cost solar panel parameter and efficiency measurement system. In the experimental study Adilah et al.  used humidity sensor, light sensor (LDR), Arduino mega 2560, LCD display and GSM shielding to develop a solar efficiency monitoring system. However, the system can deduct voltage and power of a solar panel and efficiency of the system but not the efficiency of solar panels. The system also shows limited data on LCD display and there is no description how solar irradiation (W/m2) was calculated using light dependent resistor (LDR). In another study, Anand et al.  used two Arduino Uno, photo resistor light sensor module (VEE00067), current sensor (5A range ACS712), and voltage sensor module (KG045) to develop a PV analyzer system. The system uses photo resistor light sensor to calculate the irradiation (W/m2). Again here, calculation of irradiation (W/m2) has been not disclosed. Lately, Patil et al.  developed a solar panel efficiency measurement system and for that system, the irradiation was measured using solar power meter. However, to differentiate this work from Patil et al. lux meter has been used for solar irradiation measurement process. Furthermore, details of solar radiation measurement process has been disclosed in this paper.
Moreover, in this work, a simple prototype low cost portable solar panel efficiency measurement system has been designed and developed. The system includes a single Ardunio Uno, a voltage sensor, a current sensor (ACS712), a multi meter and a lux meter. Furthermore, measurement has been taken under real sun conditions. The system not only determine efficiency but also determines maximum voltage (Vmax), maximum current (Imax), maximum power (Pm), fill factor (FF) and efficiency (η) of the solar panel.
2 Solar panel efficiency measurement system
The voltage sensor and current sensor measures voltage (Vmax) and current (Imax) individually from the solar panel and provides the relevant data to the microcontroller on Ardunio Uno R3 board. A switch has been used to select the voltage or current sensor. The Ardunio board is connected to the computer interface via USB cable. In the computer an open source Ardunio Software is installed. With this software, the source code for Ardunio Uno R3 is written and uploaded to the microcontroller. Furthermore, the solar radiation also known as input power (Pin) (measured manually by a lux meter, discussed details in Sect. 3), open circuit voltage (Voc) and short circuit current (Isc) are directly measured and inputted in the running open source Ardunio software. Once all the parameters are inputted in the software and the panel connection with Ardunio is given then the testing procedure starts and the results are shown on the screen of the computer monitor.
3 Solar panel input power (Pin) calculation
4 Experimental details
The Ardunio Uno R3’s operating voltage is 5 V. So ACSoffset value 2.5 V or 2500 mV is considered for converting voltage to current. After inputting Pin, Voc and Isc the program is executed in the open source Ardunio Software. Then the solar panels voltage (Vmax) and current (Imax) value is obtained by Ardunio module and after processing (getting at least 10 reading) the maximum Voltage (Vmax), maximum current (Imax), maximum power (Pm), fill factor and Efficiency are calculated by the Ardunio’s microcontroller using equation [1, 2, 3] and shown in the computer monitor. Then if required the result are stored and tabulated in the computer. It is to be mentioned that the Voc and Isc are measured directly under the sun with the help of multi meter (please see the Ref.  for details). Once the Voc and Isc measurement is done the solar panel has been connected with the implemented prototype system and measurement has been taken. In this work, a 10 W (0.1 m2), 8 W (0.05 m2) and 0.65 W (0.005 m2) silicon solar panels parameters were individually measured by the system at 3rd March, 2018, 12–1 P.M. (Bangladesh Standard Time).
5 Result and discussion
Data for battery/power supply
9 V battery; scale factor: 100
5 V USB power supply; scale factor: 185
Multi meter voltage reading (V)
Multi meter current reading (A)
Prototype system voltage reading (V)
Prototype system current reading (A)
Data for silicon solar panels
10 W solar panel
8 W solar panel
0.65 W solar panel
Module size (m2)
From Table 2 it is seen that, the implemented prototype system successfully measures and shows the values of Vmax, Imax, Pm, fill factor (FF) and efficiency of the silicon solar panels. For the 10 W solar panel the Vmax, Imax and Pm values are 19.80 V, 0.39 A and 7.72 W respectively. That is the 10 W solar panel is behaving like a 7.72 W solar panel at an instant according to implemented system. Furthermore, the efficiencies are found 9.65%, 8.59% and 8.4% respectively for 10 W, 8 W and 0.65 W solar panel. The efficiency can increase more depending upon the sun intensity or if the measurement is taken under AM 1.5G that is 1000 W/m2 conditions. However, generally commercially available solar panel efficiency is about to 13% [29, 30]. As the result does not differ that much in respect to 13% efficiency and as the measurement has been taken under real sun condition it can be said that the efficiency result is in good agreement with the result of commercially available solar cell. It would have been better if all the solar panels efficiency could have been measured by the commercial solar panel efficiency measurement system. But due to high price charging of the commercial solar panel efficiency measurement system, it is our future work. In general, The PV panels usually have an FF somewhere between 0.4 and 0.8 . But Table 2 indicates that the fill factor value is more than 0.8 for 10 W and 8 W panels. From Eq. 1, it is seen that fill factor value depends on maximum voltage (Vmax) and maximum current (Imax). May be because the Imax value is close to the value Isc thus the fill factor value is high. Therefore, until the fill factor value is improved, this is a limitation of this system. Further improvement of fill factor value is necessary before commercialization of this prototype. It should be mentioned that the maximum current value sometime appears as same as the short circuit (Isc) value. So a program code has been inserted so that it does not count short circuit current value even it appears. Improvement regarding this option is also a part of our future work.
In this work, a simple prototype portable solar cell parameters and efficiency measurement system has been designed and developed. The system has been developed with a single Ardunio Uno, a voltage sensor, a current sensor, a multi meter and a lux meter. The developed system measures and shows the efficiency, fill factor, maximum voltage, maximum current and maximum power of a solar panel. The developed solar panel efficiency measurement system will be able to determine any kind of (CIGS, CZTS, perovskites, tandem devices, silicon) solar panel efficiency in the direct sun if the solar panel has output contact lead. Three silicon solar panels parameters has been measured by the system. The system shows that the efficiency of a 10 W, 8 W and 0.65 W silicon solar panel are 9.65%, 8.59% and 8.4% respectively. Without considering the cost of computer and solar panel the system cost is around 40$. Which is very low compared to the commercial solar panel efficiency measurement system. The cost saving has been done by using lux meter instead of xenon arc lamp. Also the system measures efficiency under direct sunlight instead of laboratory AM 1.5G environment. Redundant power supply is also not needed for this system as the system draws power from the computer. Furthermore, the system uses low cost Ardunio microcontroller. Thus, the system overall cost is reduced in comparison with commercial portable solar panel measurement system. The system must be optimized more before it is used as a commercial product. Future research on machine learning and soft computing incorporated with this system must be given priority. In addition, research on this type of equipment must be given upmost importance as there are variant types substandard and unspecified solar panels in the market. If a portable low cost solar panel parameter efficiency measurement system is properly developed then solar panels parameters can be easily determined. Also, the customer rights to utilized proper quality product can be ensured. Moreover, a solar panel standard can be set on the market and that standard can be monitored easily with the solar panel efficiency measurement system.
The authors express their gratitude to the Department of Electronics and Communication Engineering, Institute of Science and Technology, Bangladesh for taking such initiative to do this kind of research.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no competing interests
- 1.Renewables 2017 Global Status Report. REN21 Secretariat: Option consommateurs, Paris, 2017Google Scholar
- 2.World Energy Needs and Nuclear Power|Energy Needs|Nuclear Energy meeting Energy Needs—World Nuclear Association. World-nuclear.org. http://www.world-nuclear.org/information-library/current-and-future-generation/world-energy-needs-and-nuclear-power.aspx. Accessed 23 Jan 2018
- 3.Off-Grid Solar Market Trends Report 2016 (2016) Bloomberg new energy finance and lighting global an innovation of the World Bank Group In cooperation with Global Off–Grid Lighting AssociationGoogle Scholar
- 4.Kempener R, Lavagne d’Ortigue O, Saygin D, Skeer J, Vinci S, Gielen D (2015) Off-grid renewable energy systems: status and methodological issues. The International Renewable Energy Agency (IRENA)Google Scholar
- 5.Express T (2017) Assessing solar power’s part in energy security. The Financial Express. http://today.thefinancialexpress.com.bd/anniversary-issue-2/assessing-solar-powers-part-in-energy-security-1511362956. Accessed 29 Jan 2018
- 8.Solar energy in urban Bangladesh: an untapped potential. ChE Thoughts. http://chethoughts.com/solar-energy-in-urban-bangladesh-an-untapped-potential/. Accessed 23 Jan 2018
- 9.Bhaskar U (2015) Poor quality Chinese solar modules flood Indian market. http://www.livemint.com/. http://www.livemint.com/Industry/S6DZmcPfNwhVB2gJ5Kn31I/Poor-quality-Chinese-solar-modules-flood-Indian-market.html. Accessed 29 Jan 2018
- 10.U.S. flooded with low-cost Chinese solar panels. But you get what you pay for!|Lexology. Lexology.com, 2017. https://www.lexology.com/library/detail.aspx?g=ccb73d4c-4b2b-459d-b9cc-b76c201f5f41. Accessed 29 Jan 2018
- 11.Fake and defective PV products circulating in high demand areas. ESI-Africa.com, 2017. https://www.esi-africa.com/news/fake-defective-pv-products/. Accessed 29 Jan 2018
- 15.Bian L, Zou X, Zhai Y, Liu H (2012) A multifunctional data acquisition system for photovoltaic plants. In: 2012 international conference on systems and informatics (ICSAI2012). https://doi.org/10.1109/icsai.2012.6223069. Accessed 22 Nov 2019
- 17.Adilah A, Nadzlin T, Mahadi A (2015) Development of solar efficiency monitoring system by using GSM technology. In: 2015 international conference on space science and communication (IconSpace)Google Scholar
- 18.Anand R, Pachauri R, Gupta A, Chauhan Y (2016) Design and analysis of a low cost PV analyzer using Arduino UNO. In: 2016 IEEE 1st international conference on power electronics, intelligent control and energy systems (ICPEICES)Google Scholar
- 19.Patil T, Asokan A (2016) A proficient solar panel efficiency measurement system: Using current measurements. In: 2016 international conference on communication and electronics systems (ICCES)Google Scholar
- 20.Messenger R, Ventre J (2004) Photovoltaic systems engineering. CRC Press, LondresGoogle Scholar
- 21.Luque A, Hegedus S (2011) Handbook of photovoltaic science and engineering, 2nd edn. Wiley, HobokenGoogle Scholar
- 22.Reinders A, Verlinden P, Van Sark W, Freundlich A (2017) Photovoltaic solar energy, 1st edn. Wiley, HobokenGoogle Scholar
- 23.How to convert lux to watts (W). Rapidtables.com. https://www.rapidtables.com/calc/light/how-lux-to-watt.html. Accessed 22 Jan 2018
- 26.Miyake J, Matsunaga T, San Pietro A (2001) Biohydrogen II. Pergamon, AmsterdamGoogle Scholar
- 27.ACS712 Hall Current Sensor (30A)|Open ImpulseOpen Impulse. Openimpulse.com. https://www.openimpulse.com/blog/products-page/product-category/acs712-hall-current-sensor-30a/. Accessed 27 Jan 2018
- 28.Stearns P. Solar Charger Tutorial—Part 1|Voltaic Solar Blog. Voltaic Solar Blog. https://www.voltaicsystems.com/blog/solar-charger-tutorial-part-1/. Accessed 26 Mar 2018
- 30.Solar panel efficiency—5 tips to improve their efficiency. Theecoexperts.co.uk. https://www.theecoexperts.co.uk/which-solar-panels-are-most-efficient. Accessed 26 Mar 2018
- 31.Chikate B, Sadawarte Y (2015) The factors affecting the performance of solar cell. Int J Comput Appl 2015(1):4–8Google Scholar