How To Test A Solar Panel (Explained!)

Solar Panels are becoming a great way to save money and the environment simultaneously. The solar market is growing exponentially, and thanks to new tech innovations, solar panels are finding their way into more and more businesses and homes.

Testing your solar panel is very important to ensure its quality and safety. If you care for solar panels properly, they can generate electricity for 25 years, but preventative maintenance is vital.

Testing a solar panel doesn’t need to be complicated. In this article, you will learn the basic and easy ways to test your solar panels. This article will break down everything you need to know about understanding and testing solar panels.

You’ll Learn

  • Why it is essential to test your solar panels
  • How to test your solar panel output
  • Key electrical concepts

After finishing this article, you will have the basic knowledge you need to succeed!

Solar panel being tested with a multimeter

How Do I Test a Solar Panel?

Testing your solar panel is a simple process and will just require understanding a few concepts and the ability to read a measuring device.

Here are some of the key points this article will tackle, plus a few more things you need to know;

  • Current, Amps, Wattage, Voltage, and Output
  • Testing to see if a solar panel is working
  • Testing to see if a solar panel is bad
  • Using a Multimeter
  • Measure Solar Output
  • And more

Come and see why everyone is investing in solar panels and what makes them great!

Why is it Important to Test a Solar Panel?

Solar Photovoltaic Technology (PV) testing is essential for several reasons. 

See also: Solar Panels Maintenance: Essential Tips for Optimizing Efficiency and Longevity

Physical Damage

Many things in the environment can cause physical harm to your solar panels over time. Vegetation can overgrow and cause damage to hanging wires connected to your solar panel.

Rodents and small animals can chew on the grounding of wires, eventually exposing the copper wires, increasing shocking hazards, and deteriorating your solar panel’s performance.

Birds have also been known to drop things onto solar panels, including hard objects that directly damage the device.

Regular electrical tests help identify potential faults that can occur before they ruin your solar panel.


Over the lifespan of a solar PV, these solar panels can become dirty from exposure to the elements, sometimes leading to corrosion and contamination. This process can have a significant impact on system performance.

It is crucial to address any system performance issues through testing to see if your solar panel has started to corrode.


The law in some places requires the testing of Solar PVs. This law ensures that minimum electric testing and a periodic verification report are available to make repairs or improvements. 

Sometimes specific solar PVs can have faults associated with them or have to be updated to conform to new standards as the standards change.

Fire Danger

Solar PVs, especially solar panels, are very often located on roofs so they can absorb the most considerable quantity of uninterrupted sunlight possible.

Unfortunately, solar panels have been the cause of household fires started by faults in electricity. It is a fire risk if you don’t have periodic maintenance and check your solar panels.


It can sometimes be the case that periodic testing is required to maintain the warranty on a solar panel. If you do not follow the warranty conditions, you will be left without protection.

This consequence can exponentially increase the costs of replacing and repairing your solar panel in the future.

Backsliding on preventative maintenance often has a compounding effect where the costs start to stack up exponentially.

Solar Panel Testing Basics- What are Currents, Amps, Wattage, Voltage, and Output?

This section will teach you the basic concepts needed to understand your solar panel and assess when those concepts are working correctly. You will need to understand a simple formula and what the variables mean in the formula.

You need to understand this formula because calculating these measurements is part of the solar panel testing process.

This formula demonstrates how you will calculate solar power.

Solar Power(Watts)  = Current(Amps) X Electric Potential (Volts)

Now, this article will break down what everything means.


An electric current is a constant stream of electricity moving through an electric conductor or circuit. It is the measurement of the net rate flow of electric charge through a surface, and people measure it in amps.

Current is vital in determining solar power, which is essential to understanding the results of testing your solar panel.


Amp, also short for “ampere,” is an electric unit that measures the electromagnetic force between electric conductors that hold an electric current.

It is the measurement unit for the electric current. It tells you the quality of a constant electric current. A higher amperage indicates a higher strength current.

Think of amps like the force of the water running through a river bed.


A watt measures an electric source’s power. How strong the wattage measurement determines an electric output of a solar device.

As described in the formula, 1 watt is the rate at which 1 amp current strength flows through the electric potential of 1 volt.


Voltage is the pressure a power source can exert via electricity. Voltage is essentially a measurement of a solar panel’s potential and available energy.

People measure voltage in volts, and typically solar panels are calculated in 12 volts or 24 volts.

If you are unsure which voltage your solar panel has, you can look at the specifications labels on the back of a panel or in the owner’s manual.

A common analogy used to understand voltage is voltage is like the pipes in a water pressure system. There can only be so much water flowing through the pipes, and that measurement in electricity is called the voltage.


These concepts combine to tell you an accurate electric output of a solar device. Output is the total amount of all net electricity generated and delivered at a specific time.

A device’s output is measured in watts, so the electric output of a machine is essentially its solar power measurement but taking into account the efficiency, it is delivered.

How Do I Test if a Solar Panel is Working?

To start testing your solar panels, you first need to invest in a multimeter. They are relatively inexpensive, starting at $12.99 for the economy line of the device.

  1. You want to start by figuring out your open-circuit voltage (Voc), located on the label on the back of your solar panel. You will be measuring your direct current (DC) voltage.
  1. Next, prep your multimeter by plugging the black probe into the COM terminal on the multimeter. Plug the red probe into the voltage terminal. Then, set your multimeter to a DC voltage setting.
  2. After prepping the multimeter, you need to take your solar panel outdoors and angle it directly towards the sun.
  3. Locate the positive and negative cables on the solar panel. The positive cable will be an MC4 male connector with a reb band around it. The negative cable may differ, but it won’t have a red band.
  4. Next, you will need to touch the multimeter’s red probe to the metal pin inside the solar panel’s MC4 positive connector. Also, connect the multimeter’s black probe to the metal pin inside the solar panel’s negative MC4 connector.
  5. Read the voltage displayed on your multimeter and see if it is close to the open-circuit voltage listed on the back of your solar panel.
  6. If the numbers are close enough to each other, then congratulations, you have a working solar panel.

How Do I Test if a Solar Panel is Bad?

The second standard test you can do is measuring the Short Circuit Current (ISC). This test lets you know of any danger that can tell you if your solar panel is bad.

  1. Read on the specs label the measurement for your ISC measured in amps.
  2. Set your multimeter to the amps charging. Ensure your multimeter’s fuse size exceeds your solar panel’s short circuit current. This step ensures you don’t overload your device, which can be dangerous.
  3. Set up your panel in direct sunlight
  4. Connect your multimeter probes to the MC4 connectors like the first test. There may be a spark that occurs when you connect the probes. This is part of the process.
  5. View your amp reading on the multimeter and see if it is close to matching the short circuit current rating on the solar panel specs label.
  6. If the values are close to each other, then congratulations again. Not only does your solar panel work, but it isn’t likely to be bad either.

Measuring Solar Output

Now that you know the voltage and the amps of your solar device, you can also calculate its solar output.

Again, apply the formula to get your solar output and power rating in watts.

Solar Power(Watts)  = Current(Amps) X Electric Potential (Volts)

This information will be crucial to compare at different times should you continue to periodically test your solar panel.

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Elliot has 20+ years of experience in renewable technology, from conservation to efficient living. His passion is to help others achieve independent off-grid living.

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