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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

    31 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 Louisa van Rooyen on 31 October 2016

    How do i test a panel with the multy metre? How many volts must n single panel put out on n sunny day?

    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 Johnny on 5 November 2017

    I have the same problam mine sayes arc detected that one section does not work at all

    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?

    By Bhunjun niraj on 20 May 2017

    Why solar panels cracks at the junction boxe and explodes?

    By Jim Whit on 25 May 2017

    How can junction boxes be changed easily. They are adhered with a very strong adhesive.

    By abdul wahid on 13 June 2017

    Please some Body Help me my 150w solar panel out only 12volt and 0.5 amp show i am change diode but problem not solve my solar panel only 150w and 3 diode please help me reply

    By Will on 13 June 2017

    one of my solar panels looks different to all the others so got on a ladder to see what was going on…looks like there is water or moisture trapped under the surface even though no rain in the past couple of days and the sun is out and the panel feels very hot…has something gone wrong? From a distance it looks as if the panel has shattered but if close this was not the case. How can i know if it is generating power or not?

    By James Van Vranken on 11 July 2017

    My system is not changing my batteries, in fact I charged using a generator and battery charger but 6 hours later I have lost about 20 percent of the charge. My system is struggling to achieve 12 volts. I have the inverter shut down and am not using it currently. Just trying to get the batteries charged again. This system is small, only 660 Watts. It has only been in service for about 2 months. My troubles seem to have started when I tried to run a refrigerator. I ran the refrigerator for about 24 hours and the battery should have not recovered. Is going on 4 days now.

    By Chris on 12 September 2017

    Good chance you killed your batteries. Solar batteries, especially AGMs, are highly sensitive to low-voltage or overdraw. Having a low-voltage disconnect (something that shuts your system down when your batteries drop to a certain voltage) will protect you in the future.

    By Dipak Rudra Pal on 9 September 2017

    i have a 2 KW SPV power plant. its running for 2 years. now, i have seen that for last 10 days its performance is not good. i can run only 300 watts of electronics machines by this power plant.
    now, i have chequed that no shading are there,

    how can i identify that what happen to my solar system….

    By Peter on 8 October 2017

    What does ‘Ground 1 fault PAC +0.0W actually mean other than it is not generating? It has happened once or twice before but corrected itself eventually.

    By mark norman on 5 November 2017

    Got 16 suntilite 250 watt modules on a south roof with power one inverter two strings. Inverter been changed twice and cant stop the outputs from the strings swopping over Under 1000 watts all fine output from both constant but over 1100 watts the output are 100watts different and the out puts will swop over string one 1100 string two 1500watts then swops around when sunny no cloud or shade
    Any ideas please voltage and amps seem ok and no error codes on inverter

    By David on 29 November 2017

    Hello , i have solar system complete with one battery but it has not served for a year and when i measured the charging of the panel and to from the charge controller it is giving me different voltage only decreasing after from the charger and to the loads from the battery there is very high/very fast discharge of voltage what can i do about it….

    By Resa on 10 March 2018

    My inverter shuts off immediately l turn it on. Can you help me out? My model no. is XPI-Lxxxx-B series

    By Kathy Holmes on 12 March 2018

    My mother put in a solar system (started in July, was fully up in December) and has yet to get any benefits from it. The company we used out of California has been awful. Is there anyone I can talk to who can help me trouble shoot the system. On the SolarEdge site it shows power is generating but the meter (digital for solar systems) is not running backwards and the electric company does not recognize any change. I don’t know much about systems and this has been a nightmare.

    By Pankaj on 14 March 2018

    I have one 12v 100w solar panels which is mono crystalline It is giving 20.8v and max 0.70 amp under lord when I short two wires it gives around 4 amp I have contacted two 12v 200w mono crystalline they are giving around 10.5 amp please suggest a way to improve my 100w solar panel amp

    By chip on 19 March 2018

    my bp275 panals are discolered are they still good

    By jerry on 14 May 2018

    mine jarrett solar charge controller shows the error code “E01”
    what do I have to do??

    By nick tabamo on 21 May 2018

    i have a 1 pv at 260 watts and 200 watts ang charge controller at 30 amp ang power inverter at 3000 watts i have also 2 batteries connecting in parallel, my connection of panel to contoller is good, controller to batteries is good, from batteries to inverter is also good but why it charge very slow, ang when i use 1 electic fan, my bettery charge lost slowly even the sun was in 12 o clock, pls help me ang give me advice on what i do to make my solar usefull

    By Christian on 15 August 2018

    Hi my new hybrid solar system does not find any voltage from the cells, before switching the cells on to the system, i can measure between 307 and 330 V form them, but when i switch them on the voltage drops to 2 V. can it be the connectors between the cells?

    By benn lines on 23 December 2018

    The display on my Omny 3.6/4.0KW invertor indicates that the output has dropped to 0w.
    It tries to reset every 180secs but does not. Then the screen on the Invertor goes blank for a period of anything up to 2 to 3 hours when it suddenly springs to life and starts generating electricity. This lasts for about 3 to 4 hours before in fails again.

    By Jack James on 29 March 2019

    I have 2 180w panels connected in parallel. If the clouds pass, the output drops to 11.2v. with sun its 13.7v. If I hook in series the controller has no output. I have a 12v solar batt. A mppt 30a controller. The panels are set at 45°.

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