How to test a solar panel with a multimeter? 4

It is crucial to test solar panels before you achieve the commercial operation date (COD). You have to do a demonstration and show that your solar panel project is ready to operate. Solar panels today have become the best alternative as a source of energy; you use it to power any form of an electronic device. 

This innovative technology has helped industries, homeowners and commercial businesses to cut on costs. Other forms of energy are expensive due to consistent maintenance that is called for. Good grief that solar energy is not equally demanding; the maintenance costs are low. Here is a full guide on how to test solar panels.

Everything You Need To Know About Solar Panels

When you are using solar panels, it is important that you know how to test a solar panel. Once you have installed them, you have to check the output to confirm that you are receiving the power you need. You will get the help you need and even buy your first solar panel- you might need more than one.

You need to optimize the performance and get the most out of your solar panel production. You will need to have the highest capacity factor that you could achieve. It is good to realize how effective the solar panels are performing in their installed location before you start their operation.

Electric current has two classifications, AC and DC. AC stands for alternating current while DC stands for Direct current. The direct current usually flows in one direction and is required for low voltage needs; solar panels in this case. You will need to measure your power in watts since it’s the standard unit that is set for most electronic appliances. You will perform a specific calculation for testing the solar panels.


Volts x Amp = watts.

To determine the power that the solar panel is dissipating, you need to measure the wattage and voltage.

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Measure solar panel amperage

You need to have a panel tester that is known as an amp meter. Attach the meter to the positive and negative so that you measure the amp output of your solar panels. When you are testing this ensure that your solar panel is getting full sunlight. The amp meter has to measure higher amperage that the amp output of your solar panel; you need to acquire accurate results.

Measure Current

The appropriate equipment that you need for this next step will be resisters and multimeter, which you can rent from places like TRS. The multimeter will find the DC voltage. After this, the formula used will be current = voltage.

  • Gather your resources.
  • A solar cell /Solar panel to test.
  • A good quality multimeter-an auto range preferably or one that can read current and voltage.
  • A variable resistance box. This is an easy way to vary the resistance to known settings while it is fixed in the circuit. For correct readings, I would suggest that you go through and manually measure all the resistance settings. They normally vary by 5% from the values that have been specified; mostly lower.
  • Short lengths of wire for connection.
  • A place to record your reading, this could be a spreadsheet program, a paper, and a pen. Just work with whatever you have. 

Using a Multimeter to Test a Solar Panel

A multimeter is a device that you can use to test the voltage and current of any device; including the solar panels. There are two types of multimeters.

Switched multimeter- This type of multimeter manually switches between the ranges to get the most accurate reading. While using this multimeter select the appropriate function. It has functions that measure several different quantities. To measure amperage set it to DC Amperage. To measure voltage set it to DC voltage. The readings are usually congested.

Auto Range multi meter- Switches between ranges automatically for best reading. The auto range measures voltage and current only so the only adjustments will vary between those quantities only. The readings are usually clear.

Both multimeters, besides their difference, perform similar functions in measuring the amperage and voltage of solar panels.

It is recommended that when you are testing solar panels, you have to know how to work with a multimeter. Wrong use of your multimeter could cause damage to the panels and nobody wants that. If you want to make sure that your panels are of high quality, you will find out through multimeter testing.

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Locate the converter box

The converter box is found at the back of the solar panel. After discovering it, you will have to remove the cover then you will see the connections inside.

Master Positive and Negative connections

It is crucial that you master positive and negative connections. After you have discovered the connections, ensure that your solar panel is receiving full sunlight. Tilt the solar panel in order for your solar panel to have full sunlight exposure.

Set multimeter to DC

Make sure that you are measuring at the suitable voltage level for a solar panel; measure at higher volts than what your panel is approved for. For example, if your panel has approval for 30 volts, set the multimeter to have a higher reading.

Doing this will give you the confidence and assurance that your readings will be accurate. To find out about the approval voltage of your panels, check inside the converter box and read the markings.

Connect Alligator clips

Connect the read lead alligator clips to the side that is positive. Then bring the other black lead alligator clips to the negative side and connect them. After you have completed this step, the multi mater should give you an accurate reading of volts that the panel produces.

The solar panels, especially new ones must produce a voltage that is close to the one that is approved. If the solar panel is used, the reading might be lower; this is quite usual. Disconnect the alligator clips only after you have switched off the multimeter.

Testing the 12-volt solar panel

This is the most common volts rated for solar panels therefore the testing methods will be typically similar. Ensure that you connect the black alligator clips to the negative side while the red ones to the positive side and that the multimeter is on.

Set your best fluke multimeter for electronics to over 200 VCD to ensure that the readings are correct as possible. If the multimeter indicates a function overload, you need to adjust the VCD to a higher rating since the VCD was too low.

If your multimeter is working as expected and you find no fault in it, be assured that the readings you receive are accurate. This should be the voltage that your solar panel dissipates. Keep in mind that not all multimeters on the shelf are similar; they tend to vary in monetary value and functional quality.

Testing the charge controller

During the process of testing solar panels, you need to test the charge controller. This will come in handy in the case of solar plus storage. Ensure that the battery is not fully charged otherwise it will not accept the current passing. The first two measurements use the solar panel alone. When connecting the controller, solar panel and battery make sure that you disconnect the panel from the regulator first. Then afterward disconnect the battery from the controller/ regulator.

During reconnection, connect the controller to the battery first and then the controller to the solar panel. You might be wondering why not the other way round, well this calculated steps will avoid bringing damage to the controller.

You can perform this in a series of steps below.

  • Set the measurements of the multimeter to DC Amps. Make sure that the alligator clips are in the right port to find the DC Amps.
  • Set the multimeter to 10 Amps.
  • That being done connect the solar panel to the controller and also the controller to the solar batteries.
  • Disconnect the positive cable that is between the battery and controller.
  • To find the current, you have to connect the positive cable that you have recently removed, to the lead alligator clips from the multimeter.
  • After that process, the last step should be connecting the negative lead alligator clips of the multimeter to the positive terminal of the battery.
  • This process will measure the current flowing between the solar panel, controller and solar batteries.

Final Thought

I believe that you have attained a clear picture and process of testing the solar panels and as well as why you need to perform this test. I would not want you to purchase a set of solar equipment with the wrong specifications of the panel voltage for a price that is escalated. I am sure nobody loves being cheated, at least not with an investment such as this one. The expectations with which you get a solar set should be met right when you begin using them. Testing solar panels is a question of how high-performance are solar panels you got.

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