How to Tell if Your Solar is Actually Working

How do I know if my solar panels are working?

The simplest way to check if your solar is working is to look at the inverter screen or your monitoring app during the middle of a sunny day. If the current power output (kW) is roughly 70% to 80% of your total system size, the system is operating normally.

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Most solar owners only discover a problem when they open their quarterly electricity bill and see a massive spike. By that point, the system has likely been underperforming or completely offline for months.

You do not need to be an electrician to diagnose a failing system. You just need to know what numbers to look at, and when to look at them.

Here is a simple, step-by-step diagnostic framework for the average homeowner.

Step 1: The Visual Inverter Check

Walk out to your inverter. It is usually mounted on a wall near your switchboard. Look at the LED lights.

• Solid Green Light: Everything is fine. The system is generating power and feeding it to your house or the grid.
• Flashing Green Light: The inverter is trying to connect to the grid. This is normal early in the morning or late in the afternoon when sunlight is low. If it flashes constantly at midday, you have a grid connection issue.
• Red Light or Error Code: The system has detected a fault and shut down for safety. Note the error code displayed on the screen. You will need to provide this code to a solar technician.

Step 2: The Midday Output Test

If the light is green, the next step is to verify the volume of power being produced. A green light only means the system is on; it does not mean it is producing at full capacity.

Pick a clear, sunny day around 1:00 PM. Check your inverter screen or your monitoring app for the "Current Power" or "Current Output" figure. This is usually measured in kilowatts (kW).

A healthy system will rarely produce its absolute maximum rated capacity. Heat, minor shading, and the angle of the sun all reduce efficiency. A good rule of thumb is the 75% rule. If you have a 5kW system, you should see it producing roughly 3.5kW to 4kW during peak sun. If a 5kW system is only producing 1.5kW on a perfect day, you have a problem.

Step 3: The Smart Meter Spin Test

If your inverter does not have a screen and you cannot access the app, you can use your home's smart meter.

Go to your main switchboard. Find the digital smart meter. Most modern meters have a display that cycles through various screens. You are looking for the screen that shows power being exported to the grid.

Turn off all major appliances in your house (air conditioning, pool pump, oven). If it is a sunny day, your solar system should be producing more power than your house is using. The smart meter should indicate that power is flowing out to the grid. If the meter shows you are still importing power from the grid under these conditions, your solar is either off or severely underperforming.

Step 4: When to call a professional

Do not attempt to fix solar equipment yourself. It involves lethal voltages.

If your inverter has a red light, if it is constantly restarting, or if it consistently fails the midday output test, you need to book a professional solar health check. Provide the technician with the exact symptoms you observed. The more information you give them, the faster they can diagnose the fault and get your system generating money again.