How to test a solar panel without a multimeter?

Over the years, the multimeter has been the most commonly used device to test the amperage and the voltage of solar panels. This does not mean that you can try your solar panels if you don’t have a multimeter. After researching, I found other ways to test your solar panels if you do not have a multimeter. 

Visual testing

The first thing you should look in your solar panels is the presence of any physical defects.

  • Check if your solar panel has some visible cracks.
  • Check if any hotspots, dust, or moisture might have slipped into the solar panel.
  • A solar panel should have a light sensor. If your solar panel does not have a sensor, you might consider getting one. 

In case of any of the mentioned issues, contact your solar panel provider. If the solar panels pass a physical test, you can carry out an operational test.

Using a string inverter

If you are using a smart system and a string inverter, you can test the output of your solar panels. 

  • Place your solar panels in the direct path of the sun. 
  • Connect the solar panel cables to the terminals of your inverter. 
  • If there is any sun, your solar panel will send some current and voltage to the inverter. 
  • Since you are using a smart system, you can test the total output in series and parallel connections. 
  • The strong inverter will also display the voltage and amperage of each solar panel. This way, you can quickly identify the defective solar panel. 
  • Use the findings from your inverter to calculate the wattage of your solar panels. 

If you have a multimeter, you can use this video to help you test solar panels. Trying solar panels using a multimeter is the easiest and the fastest method.

What are solar panel testing standards?

Testing solar panels is essential to know if your solar panels will serve you in the long run. You will find out if your solar panels have attained the standard qualifications set for safety. 

On the solar panel sheet, there are many acronyms stated. These are the testing standards for solar panels. Below are the top standards that you might not be aware exist. 

IEC 61730: For PV module safety

Like any other electrical appliance, solar panels are prone to electrical shock. This standard testing condition ensures your solar panels are tested for mechanical, electrical, and fire risks. If your solar panel has this approval, they have less risk of causing these hazards. 

IEC 62716: Standard Ammonia Corrosion Testing for solar panels

This is a test done to check the photovoltaic cell resistance to Ammonia. So if you live closer to a farm, you better check your solar panel’s IEC 62716 rating. Ammonia causes photovoltaic cells to degrade faster than normal.

IEC 61701: Salt Mist Corrosion Testing

For those installing solar PV systems near a beach, check if your solar panels have passed IEC 61701 test.

IEC 60068-2-68: Blowing sand resistance testing

This test is for people who people who are planning to install a solar PV system in Sandy deserts or next to dusty roads. 

Other tests include;

  • UL 1703
  • UL 61730
  • IEC 61215

These tests are standard worldwide and can be found on the solar panel manufacturers’ websites or in the user manual. 

How to test solar panel string

It is hard to tell which solar panel is not working as expected if you deal with a string of solar panels. However, you can easily test your solar panel with tools such as a multimeter or a voltmeter. 

Using a multimeter

Step 1: Change the settings on the multimeter to test the voltage

When testing the voltage, set the multimeter in volts form. Plug the multimeter into the solar panel and test the voltage. Record the total voltage of the panels. 

Step 2: Change the multimeter settings to amperes

Check the readings displayed on the multimeter and record them. 

Step 3: Calculate the Wattage of the solar panel

Find the wattage of the solar panels by multiplying the volts by the amperes. 

Volts × Amperes= Wattage

If you have a solar PV system connected in the grid-tied method with a hybrid inverter, it is possible to check the readings of your solar panels. 

  • Disconnect the utility grid and any other source of power from the grid. 
  • Check the initial reading on the control panel, which is located next to the solar inverter
  • Change the settings on the control panel to indicate the readings from the solar panel. 
  • The inverter will show the total voltage currently sent from the solar panels. It also shows which solar panel is not sending voltage and current among the solar panels. 
  • This way, you can change the solar panel that is not working. 

How to test a solar panel diode

All solar panels have diodes located at the junction box. These diodes’ main purpose is to protect the photovoltaic cells from overheating. 

If you notice your solar battery is not sending a charge to the solar battery, then the diodes might be defective. This is how you test the solar diodes.

  • Send current through the power source in the usual direction. 
  • This should be done at night since there is no power supply at night. 
  • If the diodes become active, they are in good condition. The defective diodes will register a voltage of 17.8V instead of 18V. 

DIY the solar panel tester

If you want to test your solar panel using homemade methods, you should first make a solar simulator. 

Making this simulator is a bit complicated. However, this video gives you the basics of creating and using the simulator to test your solar panel. 

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