How to Tell If Solar Panels Are Working? 4 Ways to Check

How to tell if solar panels are working? It’s a crucial question because an underperforming system can mean higher energy costs and lost savings. Factors like poor maintenance, weather conditions, or system malfunctions can silently reduce efficiency, costing you money without you even realizing it.

Spotting performance issues isn’t always straightforward. Unlike traditional power sources, solar systems don’t come with obvious warning signs. If you’re not actively checking, small inefficiencies could add up to big losses over time. That’s why regular monitoring is essential.

But don’t worry—ensuring your solar system is running at peak performance doesn’t have to be complicated. With insights from top solar panels manufacturers, we’ll walk you through four simple ways to check if your solar panels are working properly and how to keep your system delivering maximum energy output.

How to Tell If Solar Panels Are Working?

1) Indicator Lights and System Status

To check if your solar panels are working, a quick way is to look at the indicator lights on your inverter. These lights show the health of your solar system and tell you if it’s working properly.

Understanding the Color Codes

Most solar inverters use colored lights to show the system’s status:

• Green light: Your system is working and generating power.
• Red light: There’s an issue, and the inverter isn’t functioning correctly.
• Orange/Yellow light: The system is in standby or has a minor problem.
• Flashing light: The system is likely updating or restarting.

Error Codes to Watch For

Your inverter may show error codes to help identify problems:

• E001: Grid voltage is out of range
• E003: No grid connection detected
• E005: Ground fault
• E007: DC current too high
• E013: Inverter temperature too high

For SolarEdge inverters, the light status is slightly different:

• Green LED on: The system is producing power.
• Green LED blinking: The system is in standby mode.
• Red LED on: A system error has been detected.
• All LEDs off: No power is reaching the inverter.

For Fronius inverters, the light system works like a traffic light:

• Green: Normal operation.
• Yellow: Warning condition.
• Red: Error state.

Pro Tip: Regularly check the indicator lights on your inverter to catch any issues early. If you see a red or orange/yellow light, it’s important to troubleshoot right away to avoid potential system downtime or energy loss.

2) Energy Output and Meter Readings

To check if your solar panels are working, you can use real-time data from your system’s energy output and meter readings.

• Monitor Your Solar Inverter Display

Your solar inverter shows real-time data about power generation in watts or kilowatts. If you see a positive number during daylight, it means the system is generating power and working properly.

• Record Daily Energy Output

To track performance over time, record your solar production meter readings at the same time each day. Regularly comparing these readings will help you spot trends and confirm that your solar panels are producing energy.

Your utility net meter should move backward on sunny days. This means your solar system is generating more power than you’re using, and the extra energy is being sent to the grid.

• Use a Solar Monitoring App or Web Portal

If your system has a monitoring app or web portal, check the detailed insights it provides. These platforms often show: – Current power output – Daily, monthly, and yearly energy totals – Performance comparison to expected output – Savings estimates

• Compare Actual Output to Expected Performance

It’s important to compare your solar panel’s actual production with the estimates given when the system was installed. Most systems should produce within 10-20% of the expected output. If your system’s energy output is much lower, it may be time to investigate.

Typical daily energy production for residential systems is:

• 3 kW system: 6-12 kWh per day
• 5 kW system: 10-20 kWh per day
• 10 kW system: 20-40 kWh per day

Production can vary based on factors like location, panel orientation, shading, and weather. Monitoring these factors will help you see if your solar system is working at its full potential.

3) Predictable Electric Bills

Solar panels make it easier to predict your electricity costs, especially compared to relying on the grid. Once you switch to solar, your bills become more stable.

• Stabilized Bills: If your solar system covers all your electricity needs, your monthly bills usually drop to just the minimum connection fee, around $10-20. This is a low and predictable cost.
• Seasonal Bill Changes: If your system doesn’t cover all your electricity, your bills might still change with the seasons. But, they will fluctuate less compared to traditional grid power costs.
• Major Savings: Many homeowners see their bills drop by 70-90% after going solar, with more consistent bills each month.
• Fixed Payments with Solar Loans: If you financed your system with a loan or lease, your monthly payments will be fixed, giving you budget certainty.
• Hedge Against Rising Electricity Rates: Over the last 20 years, grid electricity rates have risen by 2.79% per year on average. Solar systems help lock in your energy costs and protect you from future price hikes.
• Sharp Price Spikes: In 2022, grid electricity prices shot up by 12.6% in one year, showing how unpredictable rates can be. Solar systems help you avoid these spikes.
• Long-Term Protection: A solar system lasts an average of 25+ years, providing long-term protection against rising energy prices and inflation.
• Net Metering: Any excess energy your solar system produces can be credited to future bills, helping even out any seasonal changes.
• Real-Time Monitoring: Solar apps let you track both your production and consumption in real time, helping you predict future bills.

In short, solar panels make your energy costs more predictable and save you money over time, giving you more financial stability in an uncertain market.

4) Cleanliness and Maintenance

Wondering how to tell if solar panels are working efficiently? One of the simplest yet most overlooked factors is cleanliness. Dust, pollen, bird droppings, and debris can reduce efficiency by 15-25%, and in high-dust environments, losses can reach up to 35%. A dirty solar panel means less sunlight absorption, which directly impacts energy production.

▶ How to Check If Your Panels Need Cleaning:

🔍 Visual Inspection – Look for dirt, leaves, or buildup that may be blocking sunlight.
📉 Monitor Energy Output – A sudden drop in solar production could signal dirty panels.
📊 Compare Performance Data – Use monitoring tools to track trends and spot efficiency dips.

▶ How Often Should You Clean

For most environments, cleaning every 6–12 months is enough. However, in dusty or industrial areas, more frequent cleaning may be necessary. Research shows that panels cleaned twice a year can maintain up to 95% efficiency.

▶ Best Practices for Cleaning:

✅ Use water, mild soap, and a soft brush or sponge.
🚫 Avoid high-pressure water or abrasive materials that can scratch panels.
⚠️ For rooftop systems, hiring professional cleaners ensures safety and thorough cleaning.

Keeping your panels clean isn’t just about maintenance—it’s about maximizing energy savings. A well-maintained system delivers consistent, reliable power, ensuring you get the best return on your investment.

Suggested Reading: How Often Should Solar Panels Be Cleaned?

Key Performance Indicators (KPIs) for Monitoring

1. Peak Sun Hours

Peak sun hours help determine if your solar panels are working efficiently. This measure shows how many hours in a day solar energy reaches an average of 1,000 watts per square meter. Unlike total daylight hours, peak sun hours give a better idea of your panels’ energy potential by focusing on sunlight intensity.

How to Check Peak Sun Hours

Follow these steps to measure your system’s peak sun hours:

1. Check your solar inverter’s daily energy output. This shows how much power your panels generate.
2. Compare actual output to expected levels based on your area’s average peak sun hours.
3. Use a solar irradiance meter to track sunlight intensity, especially at midday when solar power is strongest.
4. Analyze historical weather data to understand how seasonal changes affect solar energy in your location.

Peak Sun Hours by Location

Peak sun hours vary by location. Here are some examples:

• Phoenix, Arizona: 6.5–7.0 hours per day
• Seattle, Washington: 3.5–4.0 hours per day
• Miami, Florida: 5.5–6.0 hours per day

Factors That Affect Peak Sun Hours

Several factors influence the amount of sunlight your panels receive:

• Latitude: Areas closer to the equator get more sunlight.
• Cloud cover: Frequent clouds reduce sunlight exposure.
• Seasons: Sunlight levels change throughout the year.
• Weather patterns: Daily conditions impact solar energy production.
• Shading: Trees and buildings can block sunlight and lower efficiency.

Checking peak sun hours regularly helps detect issues like shading, panel wear, or system malfunctions. Keeping track of this ensures your solar setup runs efficiently and maximizes energy production.

2. Efficiency Rate

The efficiency rate of your solar panels is crucial in understanding how to tell if solar panels are working. Solar panel efficiency typically ranges from 15% to 22% for residential systems, with some high-efficiency models reaching 22.8%. Leading brands like SunPower, Q CELLS, and REC offer the most efficient panels.

Factors Affecting Efficiency Rate

Several factors can impact the efficiency of your solar panels:

• Temperature: Solar panels lose about 0.4% efficiency for each degree Celsius above 25°C. In warmer climates, you may see a slight drop in efficiency.
• Shading: Even partial shading can cause a significant reduction in performance. Minimize shading on your panels for better energy output.
• Dust and Dirt: If not cleaned regularly, panels can lose 5-7% of their efficiency. A simple cleaning can help restore some of this energy.
• Panel Orientation and Tilt: Panels positioned at the optimal angle can boost energy production by 20-30%. Proper orientation ensures maximum sunlight exposure.
• Age: As panels age, their efficiency gradually decreases by 0.5-1% per year.

How to Monitor Efficiency

To monitor your solar panel’s efficiency, try the following:

1. Compare actual energy production to rated capacity to spot any differences.
2. Use monitoring software provided by your panel manufacturer for real-time performance data.
3. Check the inverter display for detailed performance insights.
4. Analyze your utility bills for long-term changes in energy production.

Regular maintenance, like cleaning your panels and adjusting their position, is key to maintaining high efficiency. Fix any issues promptly to ensure your system stays at peak performance.

3. System Uptime

To check if solar panels are working properly, system uptime is a key indicator. Uptime means how often your panels are running at full capacity without any interruptions. A well-maintained system typically has an uptime of 95% to 99%, but several factors can affect this:

• Weather conditions: Extreme weather can temporarily disrupt the system.
• Equipment issues: Problems with inverters, panels, or wiring can reduce uptime.
• Grid outages: If the grid goes down, your system won’t work unless you have a backup.
• Scheduled maintenance: Regular maintenance can improve performance but may cause brief downtime.

How to Calculate Uptime

Follow these steps to calculate uptime:

1. Total hours in the measurement period (e.g., a year has 8,760 hours).
2. Subtract downtime hours (e.g., 87 hours of downtime).
3. Divide the result by the total hours.
4. Multiply by 100 to get the percentage.

For example, if your system had 87 hours of downtime in a year: Uptime = (8,760 – 87) / 8,760 * 100 = 99.01% uptime.

Expert Opinion: Regularly monitor your system’s uptime and downtime to identify any patterns or issues early. If uptime drops below 95%, it’s a good idea to schedule a thorough inspection to avoid future performance drops.

Mehar Naveed, Special Quality inspection at TQES LLC UK

4. Advanced Monitoring Tools

If you’re looking to track how well your solar panels are performing, advanced monitoring tools can help. These tools, which include both hardware and software, let you track your system’s energy production in real-time. This allows you to spot any potential issues quickly. Companies like SolarEdge and Enphase offer some of the best monitoring solutions available. With these tools, you can see performance at the individual panel level, which helps you spot underperforming panels or system faults early.

Key Features of Advanced Monitoring Tools

• Real-time energy production data to show how much energy your system is producing at any moment.
• Historical performance tracking so you can spot trends over time and understand your solar panels’ efficiency.
• System fault alerts that notify you of potential issues, like underperformance or faulty panels.
• Remote troubleshooting that lets you fix problems without being on-site.
• Mobile app integration to monitor your system from anywhere, at any time.

Some tools, like Fronius Solar.web, go a step further by adding weather data and energy consumption analysis. This means you can compare your system’s performance with local environmental factors, ensuring that your panels are performing as expected.

Benefits for Large-Scale Installations

For commercial solar setups, platforms like SMA Sunny Portal offer features like grid management and power plant control. These tools give you more control and are designed for larger solar systems.

These advanced tools provide detailed insights into your system’s performance. They help you spot issues that might not be obvious during a visual inspection, including:

• Efficiency declines from panel wear over time
• Intermittent connection problems that aren’t easy to spot right away
• Inverter malfunctions that could lower energy output
• Panel or string failures that affect overall performance

By closely monitoring performance, these tools can help optimize your solar energy output. You could see an energy yield increase of 5-10% compared to systems without monitoring.

Conclusion

Ensuring that your solar panels are working at peak performance is key to both financial savings and achieving sustainability goals. By regularly checking their efficiency, you not only reduce your energy costs but also help your business stay competitive in today’s eco-conscious market. Efficient solar systems play a critical role in minimizing operational expenses and boosting your bottom line.

To ensure your solar system continues to deliver top results, consider partnering with Leeline Energy. As a solar products supplier, we produce BIPV, Inverts, and Battery Storage. We can provide the optimal quality of solar panels. Explore our website now!

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