## 3 Results and Discussion
The third battery had already been used for 10 years and is also made of a silicon base (it was used so that its wear and tear can be assessed compared to the first two, which had not been used before). In the mobile application, the time of the received data can be seen and, if required, update of the data can be initiated. The use of these applications is quite convenient: since the operator is not at the control panel, but only has a mobile device, it is possible to quickly assess the state of the system and make decisions accordingly. In order to test the hybrid data transmission network and the performance of the corresponding developed software tools and the process of graphical representation of the information, pilot observations of the solar power plant were carried out. The test observations of the individual modules of the solar power plant were graphically displayed based on the data collected on the server [10]. Figure 7 shows the instantaneous voltage values of three solar panels over time. Analysing the data, it can be seen that the maximum voltage value is about 33 V, which was generated by a bifacial solar cell. Meanwhile, the maximum voltage value of a used 10-year-old solar battery was about 17 V. Such a result is possible due to mechanical damage of the individual silicon segments of the battery. In addition, very sharp spikes in instantaneous values of voltage are observed for all three solar batteries. This occurred for two reasons: first, due to the err  
Figure 2.1 Mobile application image. conditions; second, due to the angle variation between the incident sunlight and the surface of the batteries. Figure 8 presents the instantaneous values of electric current strength over time. The current strength was measured for all 3 solar panels (10 years old, silicon polycrystalline and bifacial). The trends of the current measurement curves are very similar to those of the voltage measurements. Figure 2.2 Dependence of solar battery (290 W) voltage on daylight interval: (**a**) battery used for 10 years; (**b**) new polycrystalline battery; (**c**) bifacial type battery. Figure 2.3 Dependence of solar battery (290 W) current on daylight interval: (a) battery used for 10 years; (b) new polycrystalline battery; (c) bifacial type battery. The lowest maximum current value was observed for the used solar battery and reached about 6.5 A, while the maximum current value of the bifacial type solar battery reached up to 9 A. It is worth mentioning that both voltage and current measurements were carried out under the same environmental conditions (ambient temperature, etc.). In the electric current curves it is possible to see sudden changes in the instantaneous values, which are related to changes in sunlight intensity due to cloudiness and the angle variation between the sunrays and the surface of the batteries. After measuring the voltage and current of the solar panels, the instantaneous values of electric power were calculated with the help of the software code located on the server (Figure 9). Maximum power instantaneous values were fixed for a bifacial solar battery. As can be seen, the maximum generated power of bifacial type batteries can reach up to 290 W (this is the maximum possible power for a solar battery). Meanwhile, the maximum instantaneous power value of a used solar battery of the same capacity reached just about 90 W. Meanwhile, it is worth mentioning that bifacial type batteries are about 15-20% more efficient than traditional solar batteries made on the basis of polycrystalline silicon. This trend is also reflected in the measurements, since the instantaneous maximum power of the new solar cell (made on the basis of silicon) is about 15% lower than that of the bifacial type solar battery.