Low Voltage in Solar Panel: Reasons and Fixes

Say you have been using your solar panel and one day its performance drops and it starts giving you low power. You might be facing a low voltage problem.

Low Voltage in Solar panels often happens due to the panel not getting sufficient light. Shading, Dirt Buildup, and Environment often cause this. Other things that cause low voltage are faulty wiring, degraded panel, and low-quality equipment. The most efficient solution is to ensure a good environment for your system.

As stated earlier, nine out of ten times environmental things cause low voltage in your panel. That’s why you must ensure that your panel is getting proper sunlight and that your environment is suitable. Along with that, you have to ensure good wiring and equipment.

If you are facing the ‘Low Voltage’ problem you have to understand the why first? After that, you have to diagnose all the problems in your system and take the necessary steps to fix them. In the following article, we would be discussing all of these in a step-by-step manner.

Reasons For Low Voltage In Solar Panel

To fix low voltage issues you have to understand in-depth the things that cause low voltage. If you do so it may help with multiple other issues. Regardless I will be providing an in-depth explanation regarding the most common issues.

Environmental Issue

We all know Solar Panel produces voltage by absorbing Light from the sun. If they don’t get proper sunlight. Your panel won’t be producing the voltage it should. Here comes one of the biggest problems: Shading.

Shading is when trees, vegetation, towers, building, or other stuff blocks sunlight from your solar panel. This will no doubt lower your voltage. 

Speaking about shading, it can also be caused by dirt buildup in your panel. If you live in an area where things are dusty your panel would also get dirty. 

Now another Environmental thing that tanks Solar Panel voltage production is Heat. Every Solar panel is created to operate at an optimal temperature. Many think that high temperature = high-powered Solar Panels. No! That’s not how it works. 

If your temperature is very high your Solar Module won’t perform well. And this will cause overheating. Overheating with any electronics cause performance to drop. So your voltage too will drop fast. 

Faulty Wiring

Faulty wiring will cause many hassles for you. Low voltage problem is one of them. Say you have a loose wire. Not only will this cause a fire but also mess with your voltage production. There are also other things like a blown fuse, wrong connection, bad quality cables, etc.

A well-wired system will always provide you with safety and efficiency. So if your voltage is dropping then Faulty Wiring can be one of the main culprits. 

Low-Quality Faulty Equipment

Another big culprit in various problems regarding solar panel systems. It’s common knowledge that using low-quality faulty equipment is asking for trouble.

Let’s take your solar panel. If it’s cracked, it has a hotspot and it has discolored, your panel is busted. And it will produce substantially low voltage. Not only that, use a low-quality charge controller, inverter it too will cause the same problem.

Old or Low Quality or Broken equipment doesn’t perform well. It messes up the circuit. And in turn, it also messes up the voltage production. 

How to Diagnose Low Voltage In Solar Panel?

Now that you know the main causes of Low Voltage in Solar panels, let’s discuss how you can properly diagnose the problem and fix it. There are a couple of things you have to do. These are: Testing Open Circuit Voltage, Evaluating the Circuit, and Evaluating the Environment. 

First off let’s do an open circuit voltage test. Follow these steps: 

  • Step 1: Make Sure you are using a good Multimeter.
  • Step 2: Disconnect your solar panel from your PV system
  • Step 3: Take a working multimeter and set it to DC
  • Step 4: Make sure your solar panel is getting sufficient light
  • Step 5: Take the negative lead of the panel and connect it to the negative side of the terminal
  • Step 6: Just like that take the positive lead of the panel and connect it to the positive side of the terminal

Your average 12Volt panel would be producing 18V-28V in Open Circuit. The number is 36V-56V for an average 24Volt panel. 

Now you have to make sure something isn’t going haywire in your circuit. Take your multimeter and check the voltage at various levels of your circuit to precisely find the problem. 

Now check if your Solar Panel is not getting shadowed by trees or other things. Check if your panel is blocked off by dirt. And finally, check if your panel is broken or damaged. Also, check the MC4 cable and Junction box of the panel and make sure it’s connected properly.  

How to Fix Low Voltage in Solar Panel

Now that we have performed the necessary tests on Solar Panel, it’s time to fix the problem. In the following section, I’ll provide the steps you can take to fix the pesky problem of low voltage in your solar panel.

Fixes to Environmental Issues

First of all, let’s talk about shading. A solar panel can last for about 25 years. Now trees can easily grow up and block it. It’s recommended that you perform an inspection each year to make sure some tree isn’t growing over your panel. Also, keep a regular eye so that the tree doesn’t accidentally cover your panel.

Next up, set your panel in a place that doesn’t get blocked off by trees or buildings. Make sure sunlight is hitting the solar panel perpendicularly.

Now let’s talk about dirt buildup in panels. Rain usually clears out your panel. But if the dusty wind is the everyday routine in your place, you might have to clean your panel. If your panel is way too dirty, you should call up a solar cleaning service. 

Now, let’s talk about overheating. There is not much you can do in terms of high temperature. But take some steps to prevent it. During high temperatures lower the load in your PV system. Also, you can add more solar panels to the system and connect them in a parallel fashion. 

Fixes to Faulty Wiring

Faulty occurs when you make mistake while wiring your system. The solution depends on how complex your system is. If it’s a simple battery charging system fixing it will be easy. 

But if it’s a full-on solar array system or your home’s solar panel system you better take help from an expert. Regardless we will be providing tips on how to properly wire your system.

  1. Always use good quality equipment, wires, and panels. Using Old Equipment or Low-Quality products is the main culprit in causing Faulty Wiring.
  2. Always wire equipment properly in your system. More often than not people mess up the terminal. Sometimes they don’t connect them properly, sometimes the wire gets torn, etc. Always be super careful while wiring and don’t mess up the terminals.
  3. Check for Bad connections. Use a multimeter to check voltage and various points and troubleshoot errors accordingly.
  4. If your Solar Panels have defects like Hotspot, Weird Pattern considers replacing them. Along with that if other equipment like Charge Controller, the inverter has a problem replace them if you have money.
  5. Look for physical damage in the circuit. Sometimes wires get cut off. To solve physical damage take protective measures against things that can harm your system.
  6. Always set up voltage and watt requirements according to experts. If you are inexperienced and try to use a random rating panel you will face various problems. Learn about proper electricity requirements.
  7. Try to get your circuit wired by a professional. Professionally wired circuits have nearly zero chance of being open circuits. The same tip applies if you are already facing a problem and want to troubleshoot it.

Fixes to Faulty Equipment

There is not much you can do here. First of all, identify faulty equipment. Check if your Solar Charge Controller, Inverter is okay. The easiest way to fix broken and faulty equipment is to replace them. Always buy products from reputable companies.

Reset Your Solar System

One of the most common solutions. Sometimes resetting your system fixes problems. This is true for many other electronics including solar panels. Follow these steps:

  • Step 1: Turn your solar inverter off. First of all, skip this step if you have solar panels with a microinverter. The inverter is usually a large box. Once you find your inverter locate the AC/DC toggle switch. Then Power down your Solar Inverter. 
  • Step 2: Now on to Solar AC Disconnect. Check beside the inverter. There should be a gray box with black/red handle. Turn it off by pulling the lever. 
  • Step 3: Now go to your main electrical panel. Try to find your solar breaker. (Usually labeled Solar PV). Now as usual flip that off.
  • Step 4: Memorise what you have done. Now, wait a couple of minutes (Three or Four). Take a walk. Pop a can of soda and drink it if you want.
  • Step 5: Good job if you haven’t forgotten the order you just did the steps. (Even if you have you can always look at this list). Now you have to do all the things we have done in reverse order.
  • Step 6: Go to the main electric panel and Flip the solar breaker ON. 
  • Step 7: Go to AC Disconnect Box and move the lever to ON. 
  • Step 8: Can you guess what’s next? It’s obviously the inverter. Turn your inverter on.

And finally, you have performed a hard reset. And hopefully, this resolved the problems you have had. 


Low voltage in Solar panels is a common problem we’ll all face. Fortunately, it is fairly easy to solve All you have to do is to make sure your Solar Panel is in a good environment and make sure your PV system has good quality equipment. 

Anyway if you follow this guide I hope your problem will be resolved. Along with it, you may also learn a thing or two that might help you in the long run. Regardless, I hope I managed to help you in resolving your issues.