• Category:
  • Document type:
  • Level:
  • Page:
  • Words:

sc and Short-Circuit Current IocOpen-Circuit Voltage E

  1. Aims and objectives

are PV modules using the solar panel with the material of monocrystalline silicon. sc and Short-Circuit voltage IocThe experiment aims to evaluate how the open and short circuit voltages operate when setup in room temperatures. The Open-Circuit voltage E

The experiment presents the performance of an Open and Short-Circuit Voltages. At a room temperature of 24.5oC, the open-circuit voltage has a high voltage of 21.9V compared to the short-circuit voltage of 0.12A.

  1. Introduction

The experiment is carried out to show how the Eoc and Isc react at room temperature including the characteristics of the 36-cell PV module. The experiment presents that the single 36-cell PV module leads to a high output of Open-circuit voltages and a low voltage of the short-circuit voltage. Thus, the experiment presents that when connected to the 36-cell PV module in single series forms, the Eoc voltages increase while the Isc current remains similar.

It shows the current flow of batteries when been charged from the PV Module have a positive polarity. The experiment shows that the 36-cells PV module are suited for charging batteries such as the lead-acid battery as it has a low gassing voltage, which increases safety of charging. Diodes can be used to prevent discharging while the resistance caused by parallel and series forms is the cause of the discharging as presented below.

  1. Description of the system


Figure 1: 36-cell Solar Photovoltaic Module

C.oThe figure above presents the system used for the experiment. The system is presented as a 36 cells solar Photovoltaic module. The system is used to analyze how the short and open circuit voltages react when connected to the 36cells PV solar module in room temperature. The electrical data includes the Eoc and Isc. The system is set at a room temperature of 24.5

  1. results and discussions

C, the open-circuit voltage Eoc was 21.9V while the short-circuit voltage Isc attained is 0.12A. oBoth the open and short-circuit voltages are connected on the 36-cell PV module. Once the solar panel is well placed with a stable temperature of 24.5

. On the other hand, when the short-circuit voltage is connected to the single series PV modules, the current remained similar. Thus, when using single series PV modules the Eoc increases while the Isc is constant. (Ramabadran & Badrilal, 2009)When the PV modules are connected in a series using the single PV modules, the Open-circuit voltage (Eoc) increases

At the given room temperature, the circuit is set up as shown below, to help in the determination and plotting of the E-I curve on the 36-cell PV module.


CoFigure 2: Circuit connection of the 36-Cell PV module at room temperature of 24.5

The circuit was loaded with variable loads using the potentiometer, where the varying output voltage with an increase of 0.5V were recorded as presented in the table below. Thus, the output voltage and current as recorded leading to the development of the E-I curve of a 36-cell PV module.


Table 1: 36-Cell PV Module E-I Curve Characteristics

Using the information in the table above the E-I curve of the 36-cell PV module was developed as presented below.


Figure 3: E-I Curve of the 36-Cell PV Module

The curve above presents the 36-cell PV module characteristics.

Based on the values given in the table above used to determine the E-I curve, the maximum power point voltage is at 17.5V while the PV module current at the maximum power point is at 0.11. The maximum power point (MPP) is the spot where the curvature begins.

of 12.5V, the 85% SOC is the most appropriate charge capacity. ocThe PV module can also be used to charge batteries, where the experiment involved charging the lead acid battery using the 36-cell PV module. Prior to charging the battery, the Eoc was 12.5V. The state-of-charge of the batter after charging with the PV module of 36 cells presented an 85% efficiency. Generally, the anticipated state-of-charge for the batteries is expected to occur between 40 and 70%. The state-of-charge presents the current state of the battery in se. The lead-acid batteries have commonly been used in automotive applications. State of charge presents the charge anticipated prior to having to replace the battery. Thus, the 85% state-of-charge attained for the lead-acid during the experiment is acceptable, since it stipulates the battery has a long life. More importantly, at an E

On the other hand, the output 36-cell PV module of two 18-cell PV module in the form of a series using a voltage connected to the 12V battery at the right side of the lead-acid battery as shown in the circuit below.


Figure 4: Battery Been Charged by a PV Module

Based on the above PV module, which is used to charge the battery. At the beginning of the PV module voltage, the charge cycle voltage was 13.2 while the current of the battery while it was charging had a current of 0.118. The current polarity indicates battery is charging. The point of operation of the system is located to the left knee, while the charging current is close to the short circuit current at 0.2 vs 0.118.

About 15 minutes after the battery had charged, the PV module voltages increase while the current decreases, which pushes the point of operation of the system to the knee presented in the E-I curve in figure 3. It shows the voltage of the PV after 1 minutes is 13.9V while the current s at 0.12A.

When the PV module is not illuminated by the halogen pump, the current still flows through the lamp. The measured PV voltage is 12.07V while the current is -0.002A at the battery discharge position. The polarity of the battery while been discharged presents the negative polarity, showing that it is discharged.

The resistance of the PV module in series and parallel conditions is calculated using the voltage and currents when the battery was discharged. Thus, the 36-cell PV module resistance is given by

R =V/1 = 12.67/0.002 = 63335.0

Thus, the given resistance of the 36-cell PV module is 6335.0, which is also the parallel resistance. The series resistance is given by

Rs = 21.9 – 18.5 / 0.1 = 34.2

Thus, the total resistance of the 36-cell PV module is 6369.2. The resistances are similar when the E-I curve values given in figure 3 are used.

Diodes are used to preventing discharging of batteries when charged using the PV module, mainly at night when it is dark. The diode for blocking is added between the PV module and the battery been charged as presented below.


Figure 5: Circuit with the Blocking Diode in the PV module at night

. Thus, it presents that the blocking diode has an efficiency in blocking the discharging of the battery during the night. To diode can also be used while the PV module is lightened using the halogen lamp as depicted below. (Xiao, William, & Antoine, 2004). In the dark the PV module voltage is given as -12.4V. The diode is reverse biased as evidenced by the negative voltage, which also stipulates that the current is not flowing through the PV module from the battery (Tian, Mancilla-David, Ellis, Muljadi, & Jenkins, 2012)The diode prevents the currents flow to the PV module thus, affecting the operation of the circuit


Circuit with the Blocking Diode in the PV module in light
Figure 6:

. However, it depicted that the battery has a higher state of charge when the operating point is near the knee of the battery. (Wenham, 2012)The voltage and current of the PV module in the light were measures as 14.2V and 0.119A respectively. The operation point does not change with the blocking diode in the circuit as shown in figure 3

  1. Conclusions

At a stable room temperature, the Eoc is high while the Isc is low as presented above. The Eoc voltage increases while the Isc remains similar when the circuits are connected to a single series PV module. The PV solar panels can store energy in batteries, which would effectively ensure continued supply of energy.

The Eoc of the battery differs with the differences in the state-of-change of the battery. When the current at a terminal of the battery is positive (while charging), it leaves the terminal as positive also when it is been discharged. During the charging of the battery, the operating point is closer to the knee, which is shown in figure 3, and has a higher state-of-change. More importantly, the PV cells add parallel and series resistors to the PV module.

  1. References

Ramabadran, R. & Badrilal, M., 2009. Effect of shading on series and parallel connected solar PV modules. Modern Applied Science, 3(10), p. 32.

Tian, H. et al., 2012. A cell-to-module-to-array detailed model for photovoltaic panels. Solar energy, pp. 2695 — 2706.

Wenham, S. R., 2012. Applied photovoltaics. New York: Routledge.

Xiao, W., William, G. D. & Antoine, C., 2004. A novel modeling method for photovoltaic cells. Power Electronics Specialists Conference (PESC) 04. IEEE 35th Annual.