How To Check if a Portable Solar Panel Is Working

There are many ways to check if a portable solar panel is working, but the most relevant method for you depends on your setup. You also need a few tools to test the voltage, current (amps), or power (watts), such as a voltmeter, multimeter, or wattmeter.

Here’s how you can check if a portable solar panel is working in 7 ways:

Check the portable solar panel’s LED indicator (if available).
Observe the readings on the solar generator or power station.
Check the voltage and current using the charge controller.
Measure the open circuit voltage of the portable solar panel.
Test the short circuit current of the portable solar panel.
Measure the current or power output of the solar panel.
Use an LED bulb to know if a portable solar panel is working.

Choose the easier methods to check if your portable solar panel is working. If you suspect the charge controller, battery, or solar power generator aren’t working, you can isolate the panel and test its functioning independently. Read on to know more about all these tests.

1. Check the Portable Solar Panel’s LED Indicator (if Available)

Some portable solar panels have an LED indicator. Jackery’s SolarSaga 100W Portable Solar Panel (available on Amazon.com) and other models turn on the LED indicator when they are unfolded and out in the sun. Check the LED light to know if a portable solar panel is working.

If you suspect the LED indicator is broken, you can use the USB ports next to the light to charge your phone or other small electronic devices. If the solar panel charges your device or phone, it is working. However, these tests aren’t possible if your solar panel lacks the indicator and ports.

2. Observe the Readings on the Solar Generator or Power Station

You may have one of the following setups for your portable solar panel:

Battery and MPPT or PWM (regulator or charge controller).
A combination of panels, batteries, controllers, and inverters.
Solar generator or power station with built-in charge controller

If you use a solar generator like the Jackery Portable Power Station Explorer (available on Amazon.com), you can read the input wattage on its display. The Explorer models, whether 500 or 1,000, show input and output watts in real-time. So, connect your portable solar panel and observe the power generated.

3. Check the Voltage and Current Using the Charge Controller

Suppose you don’t use a solar generator or power station. In that case, you’re probably using an MPPT charge controller and battery. The MPPT regulator may have an onboard display with the voltage and current readings, or you may have an app for the charge controller.

Check the volts and amps on display or through the MPPT app to know if the portable solar panel is working. Older charge controllers may have built-in Bluetooth connectivity, or you can use an external module to pair the device with its branded app. Then, check the real-time data.

4. Measure the Open Circuit Voltage of the Portable Solar Panel

You may want to check if an isolated portable solar panel is working, i.e., without the following components of a complete system:

Load
MPPT
Battery
Inverter
Generator
Power station

Such a quest is possible only if you have a few tools, like a voltmeter or multimeter. You can test your portable solar panel’s open circuit voltage (VOC). Here are the steps:

Set your multimeter to DCV (DC volts) as per a portable solar panel’s open circuit voltage. The VOC is higher than the nominal voltage. So, if you have a 12V solar panel, the VOC is likely between 18V and 28V. A 24V solar panel’s VOC is around 34V to 56V.
You can also check the specific VOC on your portable solar panel, usually on a plate or label at the back. However, neither nominal voltage nor VOC reading has to be identical to the rated figures.
Ensure the black probe is connected to the multimeter’s common (COM) port and the red one is in Volts. Access the positive (red) and negative (black) wires/connectors of your portable solar panel, and place the red and black multimeter probes, respectively.
Your portable solar panel is working if the reading is around the VOC. The panel is not working if you don’t get any reading or the voltage is off the charts compared to the VOC.

Perform this test when the weather is favorable for the portable solar panel. Also, ensure the panel is clean and aligned correctly, i.e., facing the sun directly or at the most effective angle.

5. Test the Short Circuit Current of the Portable Solar Panel

Like the VOC, you may find the short circuit current (ISC) mentioned on the portable solar panel or in the manual. You can test the ISC to know if it is working. Here are the steps:

Set the multimeter to amps to test the short circuit current and move the positive or red probe’s terminal to the A port.
Connect the positive and negative multimeter probes to the pins or connectors of the red and black wires of the panel.
Check the reading and compare it with the ISC you’ve noted from the manual or label.
The amps may not be as much as the ISC value, but that’s alright, much like the voltage.
However, no reading or amps detection implies the portable solar panel is not working.

6. Measure the Current or Power Output of the Solar Panel

Measuring a portable solar panel’s current or power output is an effortless exercise with an MPPT’s display or app. Solar generators or power stations will also offer you an input wattage reading. But if you don’t have such interfaces, you must measure the wattage or amperage.

Here are the steps:

Get a wattmeter to connect it in line between the solar panel and the charge controller.
Simply route the wires through the wattmeter, and the device will measure the power.
Additionally, many wattmeters display amps (current) and voltage in real-time.
If you don’t have a wattmeter, you can use the multimeter to measure the current output.
Use the same multimeter configuration when you test for the ISC (as explained above).
Connect the negative or black wire from the solar panel to the charge controller.
Connect the red multimeter probe to the portable solar panel’s positive wire or pin.
Connect the black multimeter probe to the charge controller or its female adapter.
If the solar panel works, the multimeter should read the amp output in real-time.
If there’s no or little current, your panel isn’t working, or the conditions are unfavorable.

7. Use an LED Bulb To Know if a Portable Solar Panel Is Working

Last but not least, you can use a light bulb to check if a portable solar panel is working. Choose a 12V or 24V LED bulb based on the voltage of your setup. If the light glows, your solar panel is working. Also, the panel isn’t working perfectly if the light doesn’t glow as brightly as it should.

Final Thoughts

Any reading you get on a multimeter or through the interfaces I’ve mentioned will likely be a bit off from the rated values. Also, a portable solar panel can have substantial fluctuations in energy or power output due to the sun’s position in the sky, weather, and season, among other reasons.