Skip Navigation

How to Test Solar Panels with a Multimeter

Solar panels are usually tested under standard conditions with a light source mimics the sun on an overcast day. In this blog post we will discuss how to test solar panels with a multimeter.

The following method can test your solar panel under standard conditions.
● To test the current, connect your multimeter to see if it can measure DC electricity. If so, then congratulations. You have just found a way of measuring how much power is being sent through wires without knowing what they’re doing or where their signals come from.”

● To test for voltage, set your multimeter to read AC. Connect the device onto one of your panels’ output terminals and then measure how much energy it takes from 100 – 240 volts on that specific connection point to determine what type you have.
● To measure the resistance of a solar cell or module, place one probe on wires while placing another against an insulated part. The meter will give you readings in ohms (Ω).

Step 1: Measure Open Circuit Voltage (Voc)

The instructions on the back of your solar panel should be easy to follow and will tell you how to test it.

Before buying, you should always check your solar panel’s specifications, so write down the open-circuit voltage (Voc) on its label.

To measure the voltage of a DC circuit, you will need your multimeter and two different probes. The black probe should be plugged into COM while redGEHT parallel with volts constant on each side, as shown here.

IMPORTANT: It’s essential that both parts are oriented correctly, or else they won’t give accurate readings.

If you want to measure DC voltage, make sure that your multimeter is set to read this type of energy. To select the correct setting for measuring battery charge or other phantom power sources like dimming lights with an LED module (which don’t exist), rotate dials until they align with V written on them; then find where it says “Dc.”

Place your solar panel in a position that allows it to receive plenty of sunlight. Angle the module towards direct light for optimal results.

When installing solar panels, you must match the positive cable with a red MC4 connector, and negative wires are typically black or white.

Place the red (positive) multimeter probe into one of two female molding connectors on either side to measure positive and negative voltage. Place black meter lead onto other ends from these leads for measurements to be taken against an external source such as power supply or battery pack to distinguish between them when making adjustments later down the line.”

We will need to use a multimeter to measure the voltage at our output terminals. Ensure your probe is reverse biassed before placing it on one of these negative numbers.

My solar panel’s measured Voc was 19.85V, which matches the claimed value of 19.83 volts.

The voltage you need to measure on your meter should be close but not precisely matched with what’s listed under “open-circuit.”

Proceeding to the next step means verifying your panel’s condition and finding no short circuit.

It’s essential to get accurate readings when measuring voltage levels for solar panels so that you can maximize their efficiency. If your measurements vary significantly from what they should be, then there may be something wrong with either the equipment or the installation process, and this will reduce power output above 50%. To check if everything is correctly set up on-site:

  • Make sure all electrical appliances are turned off.
  • Remove any batteries from inside phones/ watches before testing with an external battery charger (or leave them out).
  • Don’t use anything else like tools.

That might create additional sources…

● The panels should be placed where they can receive direct sunlight, angled toward the sun and not shaded.

● The solar panel should be positioned to capture as much sunlight as possible and convert it into energy.

● The output is focused on what you need to do instead of just telling me how, which I am grateful for because my laziness often gets the best of us.

● The solar panel should be clean.

Your solar panel may be damaged if you get errors or different readings every time.

How to Test Solar Panels with a Multimeter

Step 2: Measure Short Circuit Current (ISC)

A circuit panel’s short circuit current (Isc) is typically recorded as an establishment number. You will need this information for your report, so register it.
To get the most accurate reading on your multimeter, move its red probe to amperage and set it for amps (A). If you have an automatic-ranging model, then there is no need to choose the limit wisely as the manufacturer will already do this.
The multimeter you use should have a fuse size more significant than the short circuit current of your panel. For example, if 6A is recommended for an 8-gauge wire and fuses are rated up to 20 A, they’ll be perfect when testing wires with higher amps like 16 GA or 18GA, which can handle more energy without bursting into flames.
Put your panel outside in direct sunlight.
It is essential to place your multimeter’s red (live) probe on one pin inside a connector and then do exactly what it says for everything else to be tested to be accurate. Before continuing, ensure you have placed both black grounds probes onto other appropriate contacts.
Please be aware that after you complete the connection, there may be a spark between both ends. This is perfectly normal and expected behavior for your new electrical system.
You can quickly determine if an outlet is wired correctly by checking the short circuit current listed on your electrical panel.
It would be best if you ensured that the short circuit current is close to what’s listed on their label.
My panel had an Isc of 6.56A while the manufacturer claimed it to be only slightly higher at 7A; I’m not surprised by this difference as summer days typically have more humidity than winter ones and will impact how much power our devices consume (which is why you should measure voltage relatively then current). However, on clear sunny noon-time periods, both values should nearly match each other perfectly.
A solar panel’s current to voltage ratio is essential for determining its functionality. If this number matches what’s listed on the back of your electric meter, then you can be sure that everything will work as it should.
In addition to testing your solar panel for voltage and current, you can also measure open circuit voltage and short circuit currents. If these are all good, then it’s likely that there may be something wrong with either the installation process or wiring of components which could lead to other issues. Such bad connections at panels themselves- so make sure everything looks fine before moving on to step three.
If you find that your measurement isn’t close to the claimed ISC, try these suggestions and retry.
● To ensure peak efficiency, ensure the solar panel is exposed to direct sunlight.
● Make sure to test the solar panel close to noon.
● Aim the solar panel towards the sun during testing time.
● You should angle the solar panel so that no part of it is shaded.
● The solar panel should be clean.


Understanding how to save energy and money the right way is essential. It can do it not mean you should give up on your solar panels! Your system may need more power during these months because they are working harder than usual with less sun shining down upon them – ensuring that every last drop of juice made by those devices goes toward providing clean electricity for homes across America (and beyond).

Step 3: Measure Operating Current (aka PV Current)

You can measure the voltage of a photovoltaic panel (PV Current) by connecting it to your charge controller.
This is a fascinating and informative article on using multimeters with solar panels. I never knew you could measure the current output from your system, but it sounds like some easy steps will help us get started.
● Solar charge controller
● Battery
Please make sure the solar charge controller is plugged into a wall outlet before plugging it with your battery.
Connect the cables to ensure they are all connected correctly and in sequence, then plug them into their appropriate places on your charge controller.
Make sure you connect the cable that looks like a (-) symbol to an adapter with another similar sign. Make certain not to plug in either positive lead from your power source.
Once you have prepared the multimeter to measure amps, cover or turn down your solar panel so that it is not generating power.
Touch the red multimeter probe to the metal pin on one end of an MC4 connector and then gently touch it against another so they connect.
The amperage output on my multimeter measured 4.46 A, so I know this solar panel can safely power small electronics like lightbulbs and cell phones.
Try experimenting with its tilt angle and direction to get the most out of your monitor.
The current reading on my solar panel is 4.46A which means it’s outputting close to its maximum capacity, roughly 626 watts (there are different formulas for determining this). This also makes me wonder how much longer I can expect these batteries to hold out before they give up the ghost.
Energy storage systems such as batteries and solar panels are not quite perfect. While they typically produce 70-80% of their rated power in ideal conditions, you might only see production levels closer to 100% on less than stellar days.

Ch Ashraf
With over 25 years of electrical contracting experience in the Gilawala area, Ashraf Electric provides reliable and efficient residential, commercial, and light industrial electrical services. As a locally owned company based in Lodhran, we specialize in quickly diagnosing and resolving electrical issues both big and small. Our team of highly skilled electricians is available 24/7 to ensure your electrical systems continue running safely. Whether you require a full rewiring, socket and switch upgrades, safety inspections, or lightning protection systems, contact Ashraf Electric for exceptional customer service and quality electrical workmanship.