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How to troubleshoot a solar system?

This article describes how you can troubleshoot a solar system in basic steps. Common issues are zero power and low voltage output.

Troubleshooting a solar (pv) system

Below I will describe basic steps in troubleshooting a PV array.

Quality solar panels are built and guaranteed to produce power for 25 years.

For that reason, it’s most likely that a problem is caused by a defect in system components other than the panels, such as the solar inverter, charge controller, wiring or batteries.

However nearly every pv manufacturer has seen defects in solar panels over the past years, and I’ll also describe common quality issues that might shut down a pv module.

Two common problems that require troubleshooting

As mentioned above, most of the problems are caused by the inverter and charge controller.

There are two failure modes which the solar system may be experience. These two conditions which may require troubleshooting are:

  1. Zero Power Output (No Power)
  2. Low Voltage Issue

Troubleshooting: Zero power output

Zero output is a common problem and in nine out of ten cases, it is due to a faulty inverter or charge controller.

It’s also possible that one solar panel in your pv array failed. As the pv modules are connected in series, one failing pv module will shut down the entire system.

Troubleshooting: low power situation

If your solar system is not delivering sufficient power for which it is rated for, the resulting situation is called a low power situation.

This is the most common type of problem and a few, quick, troubleshooting steps will help you find the source of the problem. The factors that could contribute to a low power problem are:


This is possibly the most common cause of low voltage.

Ensure that there are no trees around and that the solar panels are not blocked by shadow at any time during the day.

Keep in mind that a solar systems lasts for more than 25 years and trees grow over time..

Conducting a bi-annual survey of the installation site is a good idea.


If shading is not an issue, most likely it will be the higher than normal operating temperature of the solar panels.

It has been scientifically proven that the voltage drop rises with the rise in temperature. The higher the temperature, the lower will be the power output.

Adding more modules in series, and therefore increasing the string voltage, will eliminate this problem.

Also make sure that there’s sufficient air circulation beneath the panels and that this open space is not blocked in any way.

Bad Connections

If the modules are not overheated, the best bet for you will be to check for a bad connection.

You can use a multi-meter to check the voltage levels at various points to find out the point beyond which the problem of low voltage begins.

If your system was professionally wired, chances are that you may not experience this problem, but it is worth checking for.

Solar panel defects

It’s uncommon for a solar panel to fail as they’re meant to last 25 years in the field.

However nearly all large pv manufacturers have seen product recalls over the past years, and therefore you mean come across failing solar panels when you troubleshoot a solar system.

There are a dozen of problems that may occur, let me mentioned the most common ones:


The series resistance of the solar cells in a panel could have increased overtime. This may be the result of hotspot that may occur when micro cracks appear in the cells.

The result is a lower voltage in the panel, which will bring the overall voltage of the solar array down.

Junction box

An increase in resistance is also likely to happen in a junction box that may be exposed to moisture.

Nowadays quality junction boxes are IP67 certified, which means they’re completely water proof.

There have been numerous recalls in the pv industry due to bad design junction boxes. The good thing is that junction boxes can be changed fairly easily.


Delamination is another common defect. You should be able to see delamination with your own eyes.

When delamination occurs, moisture can enter the electrical circuit of the panel, which may create a current leak or a short.

Other solar panel defects are PID (Potential Induced Degradation), micro cracks, UV discoloring.

A certified pv installer can help troubleshoot a solar system

After performing these basic troubleshooting steps, if you are not able to locate the source of problem, it is better to call a certified or licensed electrician.

Keep in mind that while doing any troubleshooting, there is always a potential of getting shock.

Make sure that you wear insulating shoes and gloves when performing any such work.


    Comment Section

    10 thoughts on “How to troubleshoot a solar system?

    By julius lubguban on 29 February 2016

    Mate i have my solar the inverter is no fault but there's no output everyday b4 i can see everday how much klw loading a day i want ask a help if you know someone to help me check my solar coz the installer of my solar great solar i think already bankrupt so & the my solar still warranty tnx.

    By Dricus on 3 March 2016

    Hi Julius, what's the brand of the solar inverter?

    By Sharon baldwin on 12 May 2016

    I have the same problem as this guy our reading on the meter is the same as last week even with all this brilliant sunshine we've had X only had the panels 2 years but no answers from the company when I try to ring them how do we check this the box has Elster / enphase on it

    By AFUWAPE OLUWAFEMI on 28 November 2016

    hello, which country are u?

    By Asiimwe Richard on 4 December 2016

    i have a charge controller which shows charging even to maximum during shining day but whn it comes to evening time it drops to zero and even disconnects lights. could it have issues or its battery? thax

    By Ckelectrical on 5 December 2016

    I have also a problem with no output from combimine box so what is a problem?at first everything was working good.

    By sunwell kahondo on 7 March 2017

    my solar system says grid failure and I have checked the sub board breaker its tripped. Tried to reset it and its not holding. It trips instantly as I try to reset it. Please help

    By Gary on 14 April 2017

    Inverter issue usually when breaker trips like that the inverter is blown. Please check cabling from inverter to breaker is ok if so then it's the inverter

    By Karen on 22 April 2017

    My solar system says arc detected and DC generator error. The solar company yI purchased from went out of business and I cannot find anyone to come pout and trouble shoot. We have not greeted power since 2/17/17 after Edison came to check the meter. Any suggestions?

    By Ademola on 24 April 2017

    After implementing Solar solution I notice that whenever I on d breaker from the combiner the current raises to the acquired value but within a few seconds the current starts dropping until it reaches 0amps.will like to know if it's d charge controller faults or otherwise?

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