Curious About Your Solar Panels' Non-performance ? Discover the Reasons

8 min read
why solar panel not working properly

Solar panels offer an excellent solution for achieving energy independence besides reducing power bill expenses. Beyond these benefits, they contribute to lowering carbon emissions and even enable you to earn tax credits and rebates. Reputable solar panel manufacturing companies typically provide a performance warranty of up to 25 years, underscoring their quality.

However, despite the promises of resilience from solar installers and manufacturers, every PV system requires some level of maintenance and servicing over its warrantied lifespan of 25 years.

You may have invested in solar panels and expect a certain output, but sometimes, you find that your solar power system isn't performing as per your expectation even on sunny days. Identifying the root cause of the problem can be challenging unless you have experience as a trained solar technician.

This article aims to shed some light on some common reasons why your solar panels may not be performing optimally and how to address these issues.

There are three main failure modes that a solar system may experience, requiring troubleshooting:

  1. Zero Power Output 
  2. Low Voltage Issue
  3. Zero Amperes

By understanding these potential problems and their solutions, you can ensure that your solar panels continue to deliver the expected performance and benefits for years to come.

Addressing Zero Power Output

Zero power output is a prevalent concern, and we receive queries from 6 out of 10 customers regarding this matter. However, the primary culprit behind this problem isn't always the solar panel itself. More often, it can be attributed to a faulty inverter or charge controller. Another possibility is the failure of a single solar panel in your PV array. As these PV modules are connected in series, the malfunction of one module can lead to the shutdown of the entire solar power system.

Troubleshooting Low Voltage Issues

Troubleshooting a low voltage issue in a solar power system is crucial for ensuring optimal performance and efficiency. Several factors can contribute to this problem, and identifying the root cause is essential to implement the right solutions. By carefully assessing and addressing these causes, solar power system owners can maximize their system's performance and fully harness the benefits of clean, renewable energy.

1. Faulty Solar Meter 

Sometimes, a malfunctioning solar meter can lead to issues with your solar power system. In this scenario, your solar panels may be generating power correctly, but the meter fails to accurately read the power generation due to defects or obsolescence. Additionally, poor internet connections can also disrupt meter readings.

Solution: Ensure a stable internet connection at the meter's location. If the meter is indeed faulty, consider getting it replaced.

2. Shadow Effect

The efficiency of solar panels is highly dependent on their ability to absorb sunlight and convert it into electricity. When trees or other objects cast shadows on solar panels, it obstructs the direct sunlight reaching the cells. As a result, the affected panels generate less electricity. Shading is a critical issue for solar panel installations, as it can affect not only the shaded panels but the entire solar array's performance. Solar panels are typically connected in series or parallel configurations, and shading just one panel can reduce the overall output of the entire system. Moreover, accumulated dirt, dust, pollen, bird droppings, or other debris on the surface of solar panels can create a barrier between the sunlight and the cells, further reducing the efficiency of the panels.

Solution: Ensure there are no trees casting shadows on your solar panels and regularly clean the panels to prevent dirt and bird droppings. Conducting a bi-annual survey of the installation site can help detect potential shading issues. Regular maintenance, including cleaning the panels and trimming surrounding trees or vegetation that could cast shadows, is essential.

 

Shading & Dust on solar panels

3. Length & Thickness of Wires

Voltage drops can occur in a solar power system due to various components, including wires. Wires and cables possess internal resistance, which depends on their gauge (thickness) and length. The National Electric Code (NEC) specifies minimum wire gauges based on the voltage and current to prevent electrical fires. According to NREL's study, DC wiring may experience around 2% loss.

Solution: Use shorter and thicker wires to connect solar panels and inverters to minimize voltage loss, aiming for a loss of around 1%.

4. PV Connection Losses 

PV connection losses refer to losses across wiring connectors and diodes. Solar panels have bypass diodes that enable other modules in a string to bypass a poorly performing or shaded panel. These components have a small voltage drop due to internal resistance and contact surface imperfections.

Understanding and addressing these potential issues can help optimize your solar power system's performance and ensure efficient power generation for your needs.

5. Solar Panel Defects

Solar panels, like any other energy-producing devices, are susceptible to various damages and defects that can impact their performance. The most frequently encountered types of solar panel defects are as follows:

Hotspots & Microcracks

Hotspots and microcracks can develop on the surface of solar panel cells over time. These defects can increase the series resistance of the solar cells, leading to lower voltages in the panel. Hotspots may occur due to microcracks forming in the cells, affecting the overall voltage of the solar array.

Microcracks and hotspots on solar panels

PID Effect (Potentially Induced Degradation)

PID is an effect that influences the module's potential concerning the ground and gradually reduces the power output over time. High voltage between the encapsulated solar cells and the front glass surface, grounded through the frame or structure, is a primary cause of PID. This can result in the unwanted migration of charge carriers (ions/electrons), diminishing cell performance. In cases where long string connections lead to high voltages, PID can be even more pronounced, especially under conditions of high humidity and temperature. One concerning aspect of PID is that it often becomes apparent months after the photovoltaic system installation, and unlike other defects, it is not visually distinguishable.

Delamination

Solar Panel delamination

Delamination is another common defect, typically visible to the naked eye. When delamination occurs, moisture can infiltrate the panel's electrical circuit, potentially causing current leaks or shorts. Delamination in solar panels arises when the laminated components become separated.

The severity of delamination determines the extent of the problem, often starting at the edge of the solar panel and gradually spreading. Glass-manufactured panels, as well as thin-film or frameless PV panels, are particularly susceptible to significant damage when corrosion and moisture-related issues are left unchecked.

Identifying and understanding these common solar panel defects is essential for proactive maintenance and timely repairs. Regular inspection and early intervention can help ensure the longevity and optimal performance of your solar power system.

Have Voltage But Zero Amperes 

Solar panels with voltage but no amps are often caused by an open circuit, incomplete or flawed wiring, or equipment issues. A wrong measurement technique, like connecting a multimeter in parallel and blowing its fuse, can also be a culprit. Understanding these factors is essential to avoid such problems. Regular inspection and early intervention can help ensure the longevity and optimal performance of your solar power system.

1. Open Circuit:

An open circuit occurs when the electrical circuit is either incomplete or not properly configured. In this scenario, current flow is obstructed, even though there is voltage present in the system. This problem can be caused by various issues such as:

  • Broken Charge ControllerThe charge controller is a crucial component that regulates the flow of electricity from the solar panels to the batteries or the grid. If the charge controller is malfunctioning or broken, it can prevent the current from flowing properly, resulting in zero amps.
  • Reversed Terminal Connection: Incorrectly connecting the positive and negative terminals of the solar panels or other components can lead to an open circuit and zero amp output.
  • Solar Panel ShadingIf part of the solar panel is shaded by obstructions like trees or buildings, it can create an open circuit, reducing or stopping the current flow

2. Mismatched Load Voltage 

Solar panels generate electricity, and the voltage they produce is proportional to the amount of sunlight they receive. When you connect a load (e.g., a battery or an appliance) to the solar panel system, it should have a voltage rating compatible with the solar panel's voltage. If the load voltage exceeds the solar panel's voltage, the current may not flow properly, and the system can end up with zero amps despite having voltage.

3. Solar Charge Controller Error 

The solar charge controller is responsible for regulating the amount of charge going into the batteries. If the charge controller is malfunctioning, damaged, or of low quality, it can stop the flow of current, leading to zero amps in the system.

4. Solar Panel Internal Problems

Internal issues within the solar panel itself can also cause zero amp output despite having voltage:

  • Loose MC4 Connectors: The MC4 connectors are used to connect multiple solar panels together. If these connectors are loose or not properly connected, it can disrupt the current flow.
  • Junction Box Problems: The junction box of the solar panel houses various electrical connections. If the mechanism inside the junction box becomes loose or damaged during shipping or handling, it can lead to zero current flow.
  • Cracked Panels and Hotspots: Physical damage to the solar panels, such as cracks or hotspots (localized overheating), can affect the overall performance and result in zero amps.
  • Shading: Shadows on the solar panels due to nearby objects or dirt can reduce or eliminate the current generation.

5. Wrong Measurement Method

Sometimes, the problem lies not in the solar panel system but in the measurement process:

  • Using Wrong Multimeter Settings: When measuring the current with a multimeter, using incorrect settings like AC instead of DC or improper range can give false readings of zero amps.
  • Improper Multimeter Wiring: Incorrectly connecting the multimeter to the solar panel system can lead to inaccurate readings.

To address these issues and ensure optimal performance, it is essential to perform careful inspections, troubleshoot systematically, and fix or replace any faulty components as needed. Regular maintenance and attention to these potential problems can help the solar panel system operate efficiently and generate the expected amount of power.

Suggestion to the solar system owner

After conducting these fundamental trouble shooting steps, if you still cannot pinpoint the source of the problem, it is advisable to seek assistance from a certified electrician or contact your solar system installer. It's essential to recognize that troubleshooting electrical systems carries the risk of potential shocks. To prioritize safety, always wear insulating shoes and gloves when engaging in any such work. The expertise and experience of a professional can help identify complex issues and ensure proper and safe resolution, minimizing any risks associated with handling electrical components.

Conclusion of this discussion

Solar pv modules provide numerous benefits, including energy independence, lower utility bills, and reduced carbon emissions. While reputable manufacturers offer warranties up to 25 years, ongoing maintenance is essential to ensure the longevity of the system. Troubleshooting zero power output and low voltage issues are key to identifying potential problems. Common issues may arise from faulty inverters, shading, or wiring complications. Understanding defects like hotspots, microcracks, PID effect, and delamination can help in early detection and timely solutions. Regular inspections play a crucial role in maintaining optimal performance and securing a sustainable energy future. If troubleshooting doesn't identify the issue, consult a certified electrician or your solar installer. Remember, electrical work carries risks, so wear insulating shoes and gloves for safety. Their expertise ensures proper and secure resolution of complex problems.

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2 comments


  • pete sarullo

    six panels. each has correct open circuit volts. each ohms out at 0.00. array is producing correct 250v at combiner box in and out. charge controller will not recognize the array. same charge controller will recognize adjacent array and charge correctly when swapped over. faulty array will not work with other charge controller. help


  • Engineer Ogooluwa

    It is technically helpful !!!


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