12V Solar Panel Not Working: Reasons and Fixes

So why Is Your 12V Solar Panel Not Working? This is one of the most common questions of a solar panel owner. And solving this is pretty straightforward. 

The Main Reasons your 12V Solar Panel may not be working are Wrong Wiring; Faulty Panel; Faulty Equipment; Bad Environment and many other trivial things. First of all, you have to identify the issue and then troubleshoot it.

So the first step is to learn a bit about how a 12V solar panel work. Then we have to review all possible things and issues it might be facing. After that, we have to know how to diagnose and identify the problem. And finally, solve.

In the following article, I’ll provide a step-by-step guide on how to identify and fix your trusty 12V Panel which is not working. So stay tuned.

How Does Your 12V Panel Work?

Before we identify our problems, it’s recommended to know a bit about how your 12V panel work. Well, first of all, if you are using a 12Volt Panel be sure to use equipment compatible with it. i.e. 12V battery, 12V inverter, and at least a 12Volt Charge Controller.

Now take a look at the back of your panel and check how many watts it is. Then divide the watts by volt. For example, let’s say you have a 100W/12V panel. And this will produce about 8.33 amps per hour during sunlight.

Now a common question comes up. How long will it take me to charge a battery? Well, it’s simple math. Divide your battery capacity by the amp you will be charging it at. Say you charge a 100 amp hour battery in 8.33 Amp. So it’d take approximately 12 hours or half a day.

Why is your 12 Volt Solar Panel Not Working?

So here you are? Your panel is broken. Well, there are a couple of issues you need to understand if you want to have a shot at fixing them. Here are some of the common issues which cause Solar panels not to work.

Zero or Low Amp Issues

Amp is basically the lifeblood of your PV system. If it’s zero or very low, your panel won’t work. So why is your panel having zero amp?

Well, an open circuit aka faulty solar panel wiring may be one reason. Another reason is the well-known solar charge controller errors. Basically, your Solar Charge Controller goes haywire and stops current flow. 

Finally, Internal Problems within the Panel will definitely cause zero amp issues. Maybe the problem was with your panel after all.

Zero or Low Voltage Issues

Ah, a problem quite common as the first one. Remember Ohm’s law. V=IR. Well if your V aka Voltage is zero then I aka Current is also zero. And your solar panel won’t work. So why is your voltage zero?

The two main causes are ‘Broken Solar Charge Controller’ and ‘Broken Solar Inverter’. If you are using a solar array, one busted panel in any of them will also cause zero voltage issues. 

Also keep in mind that, things like shading (something obstructing sunlight from panel); dirty panels; really high temperature, and defective panels will lower voltage and cause issues. 

Faulty Solar Panel

The Classic one. A faulty solar panel won’t work no matter how hard you try. An internal fault is hard to fix. And will cause issues nine out of ten times.

Problems like loose MC4 connectors and Junction Box Problems are fixable. But things like cracked panels, weird patterns in panels, and old panels are almost always impossible to fix.

Problems With Other Equipment

First of all, be sure to use quality equipment. In your PV system, you need a good solar charge controller, a good inverter, and other good stuff

If a single one of your equipment is busted the system won’t work. So check every piece of equipment.

Other Trivial Issues

Aside from all of these, there are multiple other trivial errors that can botch your system. Bad wiring is the usual culprit. Other things are using incompatible equipment; overcharging the battery, directly connecting the battery, and other issues. Most of them can be fixed if you have basic knowledge regarding solar panels.

How to Diagnose Problems with 12V Solar Panel?

Now that we know all the reasons things could go wrong, we have to identify our problem. We have to do a couple of tests and make sure what is actually causing problems.

Checking the Amp of 12V Panel

  • Step 1: Get your solar Panel onto a nice sunny place, there should be no load on it yet.
  • Step 2: Set your Multimeter to DC Volt settings.
  • Step 3: Connect the negative terminal to negative and positive to positive and hook up the multimeter to the panel. The Red Part would be connected to the Voltage Slot in Multimeter.
  • Step 4: Note Down the Volt
  • Step 5: Now Disconnect the system and set your multimeter to DC amp
  • Step 6: Reconnect the system like in Step 4. This time the Red Part should be on the Amp Slot.
  • Step 7: Note Down the Amp
  • Step 8: Now compare them with the rating of your Solar Panel

After doing this if you are getting zero amp then the problem may be with the panel itself. (Considering you used a good multimeter). 

Now we measure with Load.

  • Step 1: Make Sure Your System is wired properly
  • Step 2: Set Parameter as DC Voltage and connect your multimeter in parallel to your circuit. And take note of the voltage.
  • Step 3: Set Parameter as DC Amp. And Connect the multimeter in series to your circuit.
  • Step 4: Take Note of the Amp. And compare them with your Panel’s rating.

If you still get zero amp then, your wiring is busted or something is wrong with your system.

Checking the Voltage of 12V Panel

First of All Let’s test Open Circuit Voltage.

  • Step 1: Take Your Multimeter and Set it to DC;
  • Step 2: Disconnect your Panel from System;
  • Step 3: Take the Negative Lead and connect to the Negative Terminal of the Multimeter;
  • Step 4: And just like that take the positive lead and connect it to the Positive Terminal.

For a 12Volt panel you should get from 18V to 28V;  

Checking the Solar Charge Controller

  • Step 1: Connect the negative side of the multimeter to the negative wire of the charge controller.
  • Step 2: Do the same for the negative one.
  • Step 3: Read the multimeter.
  • Step 4: If it’s zero/ no current then, reset the controller. Disconnect it and then reconnect it.
  • Step 5: Repeat the Process till Step 3.

If you still get zero, your Charge Controller is busted. 

Checking the Inverter

If something is wrong with your system your Solar Inverter will start flashing light. Go ahead and reset the inverter.

Another issue is noise from the Inverter when there is no current. That means that the broken thing needs a replacement.

Checking For Environmental issue

Make sure your solar panel is getting proper sunlight. Nothing is shading it. Check if something is messing up the circuit. (Like tress and other environmental stuff). Make sure your panel is clean and tidy. And please make sure high temperature isn’t destroying the panel’s efficiency.

Checking the Panel’s Integrity

Just make sure your panel isn’t damaged. Check for cracking; weird patterns or hotspots. Also, make sure your MC4 connector isn’t loose and the junction box is fitted properly. You should easily be able to spot anything that is broken with your panel.

Solutions to Issues With 12V Panel

Here we will talk about how you can fix those annoying problems we just discovered. So without further ado, let’s start. 

Solutions to Open Circuit

1. Ensure your Solar Panel is getting proper sun. Shading is a big problem with Solar Panels. Be sure to put your panel in a sunny spot.
2. Always use good quality equipment, wires, and panels. Using Old Equipment or Low-Quality products is the main culprit in causing Open Circuit.
3. 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.
4. Check for Bad Connection. Use a multimeter to check voltage and various points and troubleshoot errors accordingly.
5. 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 problem replace them if you have money.
6. Be Careful of Overheating. More Temperature equals Less Current Flow. Overheating is a big culprit of an open circuit. Always ensure the safety of your circuit and system and monitor any overheating.
7. 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.
8. 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.
9. 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.

Solutions to Solar Panel’s Internal Problem

Let’s talk about Loose MC4 cables. It is highly recommended that you take help from an expert while fixing it. What happens here is the terminal is not actually fully inserted into our MC4 connector. 

Due to not making full contact problems occur. Here is how to fix them.

  • Step 1: First we loosen up the back gland of the connector with a screw.
  • Step 2: Now pull the MC4 connector to check if it pops out.
  • Step 3: If it pops out it means your MC4 connecter is loose. Now push the MC4 connector in until you hear a click. Make sure the connector is fully seated.
  • Step 4: Put back the backward gland.

After following this your MC4 connector will be fixed.

Now to the junction box. These are located in the back of your Solar Panel. You can open them and check if they are screwed up properly. If not screw them up properly. 

It’s recommended that if you have problems in your junction box seek help from the experts.

If your Solar Panel has cracks or hotspots or other physical damage, you have to replace it. There is no way I know of that can easily fix such damage.

Troubleshooting The Charge Controller

If your solar charge controller is showing a problem moon error symbol, zero power, frozen display, etc. it may cause the zero amp problem. The easy fix is to reset your solar charge controller.

As with any electronics resetting works like a charm. A quick restart can easily resolve the solar panel not charging the battery. There are two types of reset. Hard and Soft. Try the soft one before attempting the hard one.

A soft reset is simple. Press the reset button and restart your charge controller. In some models, you have to press both the power and the reset button and in some four buttons together. 

Its screen will blink and flash and soon after it will return to the same display screen. It’s basically like rebooting a phone. 

Hard Reset is basically disconnecting the system. Do this night if you attempt it. Disconnect the load first, then disconnect the panel. Do not forget in which order you disconnected the wires. 

Wait like two to ten minutes. It depends on the controller. Reconnect the wire in the same order you disconnected them. 

In most cases, a soft reset is enough. If it is not working attempt a hard reset. Resetting Solar Charge Controller is one of the most common solutions if your Solar Charge Controller is not working properly. 

Also if resetting doesn’t fix the problems with Charge Controller consider replacing them.

Solutions to Faulty Equipments

The best advice I can give is to replace them. Fixing faulty equipment is a hassle in itself. If money isn’t your concern please consider buying high-quality equipment. Actually, this will save you money in the long run.

Solutions to Other Trivial Issues

Aside from all these, there is a multitude of reasons your solar panels may not work. A couple of general rules are wiring your circuit correctly, using compatible equipment, not using cheap or old things, making sure your solar panel is clean and getting proper sunlight, and ensuring all of your equipment and performing well.

And finally, if you are unsure about anything always feel free to take help from professionals. And please consider reading my other articles. You may find more about general solar panel issues.


12V Panel is a very common choice amongst customers. And many face issues with it while trying to use this. Fortunately, these issues are fairly easy and simple to fix. There are a couple of things to keep in mind:

  1. Always wire your circuit properly.
  2. Always check inverters, charge controllers, and other equipment and replace them if needed.
  3. Always keep your panel clean.
  4. Always seek help from a professional if you are unsure about what you are doing.

With proper knowledge and understanding, problems such as this can be fixed easily. And as always, I hope this article helped you in resolving your problems.