It can be frustrating to find you don’t have voltage from your solar panels, but the potential problems are relatively straightforward to diagnose as there can only be a few issues that cause the lack of power.
Common problems with zero voltage include a faulty inverter or charge controller, a solar panel that has failed, shading, increased temperature, hotspots in a solar panel, poor connection or faulty wiring, and delamination caused by water entering one of the solar panels.
We will look at the most common scenarios where PV systems fail:
- Inverter fault or failure
- Charge controller fault or failure
- Solar panel failure
- Shading, temperature, panel, and wiring faults
Knowing what kind of issue you are dealing with and how to troubleshoot it effectively can save you money and time and quickly get your system back to operation.
Solar Panel: No Voltage Or Zero Power Output Solutions
This is quite a common problem, and the most likely causes are a fault or failure with the charge controller or inverter or a panel in your array that has failed.
To troubleshoot this issue, you will need to test the inverter, the charge controller, and the solar panels to determine where the fault lies. To do this, you will need a multimeter that can confirm whether there is voltage output.
Solar Panel: Test The Inverter If There’s No Voltage
This is the most straightforward step, as most inverters have warning systems and indicators that activate when it detects a fault. If you find there is no voltage, check the inverter and see if the warning lights are flashing.
If they are, then you need to reset the inverter. See if this solves the issue; if it doesn’t, disconnect the inverter for a few minutes. Then reconnect the wires and see if there is voltage.
When you reconnect the inverter, you should hear a ‘click’, and some may emit a low hum, but any other noises and the inverter are probably faulty, and you will need a technician to come out and check it.
Most inverters also come with monitoring systems. You can check the inverter data logs to see if there was a sudden drop or loss of power, and if you have eliminated other possible causes, then your inverter may well be faulty.
See also: Solar Panels Maintenance: Essential Tips for Optimizing Efficiency and Longevity
Solar Panel: Test Charge Controller If There’s No Voltage
You can test the charge controller using a multimeter. Connect your multimeter carefully to the positive and negative outputs and see whether there is a voltage reading or not.
The controller regulates the voltage and amperage to the batteries to make sure they don’t overcharge, so if you aren’t getting power from your system, you may well have an issue with the controller.
Using the multimeter, you can check the voltage coming from the controller, and if you find that it is low or zero, you may have a problem there.
However, you need to remember that the charge controller receives power from the solar array, so you will need to check whether there is voltage from your solar panels before confirming an issue with the controller.
How A Faulty Solar Panel Creates No Voltage
Because solar panels in an array are connected in series and if one fails, the whole system goes down and there will be no voltage or current as a result.
To test whether you have a faulty solar panel, you need a multimeter to check for voltage and current on the array and individual panels. First, you do the VOC or PV Open Circuit Voltage Test.
Set your multimeter to DC and disconnect the panel from the system. Then connect the positive lead from the multimeter to the positive output from the panel and the negative lead to the negative panel output.
For 24V panels, you should get a reading between 34V and 56V, while on 12V panels, that reading should be between 18V and 28V.
If you get lower than this, or no voltage, the panel is faulty.
You need to switch the multimeter to (A) and then repeat the procedure above to check for current. Most multimeters have a minimum current setting of 10A, which is perfect.
Once the multimeter is connected, you should get current readings of between 3A and 9A from the panel – if you get zero amps or lower than 3A, then the panel has a fault.
Tip: if you don’t have a multimeter, you can load test the panel by connecting a 12V light bulb to the positive and negative outputs of the panel- if you get light, all is well!
Solar Panel: What Other Problems Can Result In No Voltage?
Aside from the above, high temperatures, shading, panel damage, and faulty connections can cause a lack of voltage from solar panels.
How High Temperatures Can Cause Voltage Drops In Solar Panels
All electronic devices, including solar panels, operate far better at lower temperatures. When the temperature rises, voltage and power production reduce accordingly, so very high temperatures will cause your voltage to decrease.
You can reduce the load or add more panels to your array to resolve this.
Shading And Dust Are Common Cause Of Voltage Drops
Shade reduces the level of solar radiation received by the solar panels, and dust does the same. So ensure your solar panels are cleaned regularly to maintain production and check the trees at least twice a year to ensure that they are not creating shade.
Solar Panel Failure Or Damage Can Cause Low Voltage
Any fault with a single panel will cause the whole system to fail, and if water has entered the panel, or there are cracks, hot spots, and discoloring can all result in poor generation performance.
If you see any of these issues and your panel is under warranty, you can get it replaced at no cost, but you will need to get a technician out to inspect and change the panel.
Faulty Wiring Or Blown Fuses Will Cause Voltage Problems
If you have established no issues with your inverter, controller, or panels, you need to check for poor or loose connections in the system or a blown fuse. Before you look for hardware issues, check for a fuse problem, especially if the system suddenly fails.
Use your multimeter to check voltage and current readings at various points to check whether all the connections are stable. Where you see voltage drops or no voltage, you then need to check whether a wiring connection has frayed or broken and has possibly blown a fuse.
The problem is a simple one to troubleshoot and repair, while major issues don’t occur that frequently. So, a logical process will speed up the identification of the fault and allow faster system restoration.
Resources
https://www.fluke.com/en/learn/blog/hvac/troubleshooting-photovoltaic-systems-three-typical-problems
