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:
Zero Power Output (No Power)
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.
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.
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.