Solar Panel Not Charging Battery: Causes and Solution

Say you buy a solar panel and connect it to your battery to charge it up. But when you come back you see the solar panel hasn’t done a thing. Sounds Relatable? Your battery not getting charged properly is a common problem. The reasons vary but the solutions are simple.

If your solar panel is not charging your battery properly the likely culprit are mainly: Wrong Solar Panel Setup, Equipment Problems, Internal Problems of the Battery or Faulty Battery, and Solar Charge Controller Issues. The easiest way to fix them is to replace faulty equipment. 

In case of a Solar Charge Controller Problem resetting it and connecting the Solar Panel, Charge Controller, and Battery Properly.

The environment also plays a factor but that’s rare. Bad weather conditions can lead to your solar panel not getting the needed sunlight. Without sunlight, It won’t work and thus the battery won’t charge. So be sure to check if your panel is getting proper sun.

As we can see there are various problems that can stop your panel from charging your battery. The reasons are quite small; so they can easily be fixed if you have basic knowledge of electrical equipment. Regardless in the following article, we will discuss how to check if your battery is getting charged, why is your panel not charging your battery, more about system wiring fault, faulty battery and charge controller settings, and how to fix each of them in detail.

How To Check If Solar Panel Is Charging Battery?

Sometimes the biggest problem is people not knowing what on earth is actually happening. You may be thinking ‘what is causing the problem?’ It is a recommended practice that you check each part of your system and whether those are working properly.

Before we cure the disease we have to identify it. So it is highly recommended that you check if your solar panel is charging the battery. By checking or testing you may easily identify the key problem. Here are the steps on how you should proceed.

  • Step 1: Buy a multimeter and connect it to your system. It can be used to measure the voltage of your panel. Be sure to do it with your solar panel in sunlight (Note: If you are unable to measure voltage it is your solar panel that has the problem)
  • Step 2: Now take your battery and measure its voltage. If your voltage is way too high or the opposite way too low your battery will be facing issues while charging.
  • Step 3: Now on to Solar Charge Controller. Check its terminal voltage. The terminal voltage should be in range. If the voltage output is weird and undefined, your solar charge controller is facing a problem.  
  • Step 4: Double Check your Equipment. Things like broken Alternators, Regulators, Solar Panel Defects, Delamination, Bad Battery, Broken Charge Controllers, and Broken Diode in Panel must be double-checked. 
  • Step 5: Assess your environment. Check if you placed your solar panel is set up properly in a sunny place. Extreme Temperature, Overcast, Shading, etc. will cause problems.

Now that you ran a general diagnosis on your system you are ready to fix your problem. But before that, you have to understand the problem in detail. In doing so, the problem will be very easy to solve. 

Why is Solar Panel Not Charging Battery?

As stated earlier there are many reasons why your solar panel can decide to stop working. Including bad wiring to broken equipment. Below we discuss the most common causes in detail.

Faulty Solar Panel

One of the most obvious things is your solar panel is broken. Thus it is unable to provide you with enough voltage to charge the battery. Here are some common faults with solar panel

Hot Spots:  If you are using your solar panel for a long time Hot Spots are bound to appear. If you look at your panel you’ll see part of the panel is covered by shadow. And this spot will have a greater temperature thus hotspots appear. Soon it damages the solar module and grid line and soon your solar panels lose efficiency.

Weird Pattern: Your panel can get cracked easily. And water will seep into it as a result. Now factor in the Sun. Inside the PV Cell, a weird reaction occurs that can create weird patterns on your solar panel.

Cracked Panel: Your panel may already be cracked. It is hard to notice cracking with naked eyes. Crack often causes mechanical failures and reduces power output this destroying the solar panel day by day

Broken Diode: If your panel by any chance has a broken diode and you are connecting your panel directly to your battery current flow will reverse at night and drain your battery. Be careful of this phenomenon. Maybe your solar panel is getting drained and you are not noticing it. 

Low-Quality Panel: If you are using a Cheap Solar Panel or a Very Old Solar Panel, there is a chance it will not work. Old or low-quality product has faulty internal circuit and can get busted at any time. Thus trying to use old or extremely low-quality solar panels can cause problems like the battery not being charged.

Faulty Battery

Now onto the Battery. If you are trying to charge a broken battery it will not work at all. Also, don’t try to charge incompatible batteries with Solar Panel. (For Example Car Engine Starting Battery). Ways to identify a faulty battery is to look for leakage, discoloration, budge, etc. 

Another problem that happens is when you don’t charge the battery for a long period of time or it runs out of power and you let it sit idle for a long time. In that case, you can’t directly charge your battery using Solar Panel.

Broken Equipment

Nine-time out of Tens this happens. In that case, you will definitely have zero power output from the panel. So what is broken? 

Most commonly the culprit here is either the inverter or the charge controllers. But do note other things can be broken too. Be sure to check your regulator too to see if it is busted or not. Be sure to check all the equipment related to the charging system needs to be fully functioning. 

Wrong Setup

Without a proper setup for Solar Panels, Charge controllers, and batteries you’ll end up with a non-functioning system. One mistake people do in setup is to connect Panels to Batteries directly. It’s highly recommended to use a solar controller. The wrong setup includes improper connections, bad connections, and messing up the positive and negative pole connections. Also, add in Open Circuits and Voltage mismatch. 

Another key part of the Wrong Setup is the environmental factor. Your solar panel won’t work in extreme weather conditions or without proper sunlight. If there are trees near your solar panel the shade will lower your voltage and charging won’t happen. 

Faulty Solar Charge Controller

Your solar Charge Controller can be broken. In that case, your battery won’t be charged. Usually, low-quality charge controllers have this problem. Sometimes the Charge Regulator gets damaged and needs replacing. Also, Solar Charge Controller can have various problems like moon error symbol, display freeze, and no power which will in turn cause problems charging your battery.

Also, your solar charge controller settings can all be messed up. If you have an advanced interactive Solar Charge Controller make sure you don’t accidentally set up some unknown settings. 

How to Solve Solar Panel Not Charging Battery?

Now you know why these pesky problems occur. It’s time we learn about how to fix each of these problems simply and efficiently. We will be discussing exactly that below.

Solution for Faulty Solar Panel

If your power output from a solar panel is zero, then go and look at the wiring first. Make sure that positive and negative poles are not reversed. Then make sure your panel is not getting handicapped by shadows or weather. Then check if the specs of the panel are correct. The open-circuit voltage has to meet the requirement of the controller. Also, be sure to not use overpowered solar panels. 

If this fails and your solar panel fails to function properly, it is most likely that it is broken. If you are using cheap low quality or old panels consider replacing them. Otherwise, if you spot Hot Spot, Weird Pattern, or cracks on your panel, it’s time to replace it.

Solution for Broken Battery

Your battery capacity needs to be reasonable.  Be sure to check if your battery is dead (You will see no voltage from the battery in that case). If you are trying to use a broken years old battery it won’t work. Take good care of your battery and refrain from using low-quality ones. Also, refrain from trying to charge incompatible batteries. 

One crucial problem that happens is you let your battery sit idle for a long time. Then it becomes hard to charge the battery using the solar panel. Check your battery voltage and if it is low fill it out with a current charger. 

If your battery is badly damaged and isn’t working at all it’s time to use a new battery.

Solution for Broken Equipment

If your charge controller or other equipment is broken it is highly recommended that you replace those and buy new ones. If you are confident in your skills you can try to self-repair it but replacing the broken components is easier. 

Correct Setup Guide

Here is a quick setup guide on how you can charge your battery with a solar panel. 

  • Step 1: Connect your solar charge controller to the battery. Do not connect the panel before doing things. While connecting the battery and solar charge controller. 
  • Step 2: Make sure you connect the positive and negative poles properly. (Positive Wire on Positive Terminal, Negative Wire on Negative Terminal)
  • Step 3: Now check the voltage of the solar panel in sun. The voltage of the solar panel must be greater than the voltage of the battery.
  • Step 4: Connect the Panel to the Solar Charge Controller. Don’t mess up the positive and negative sides.
  • Step 5: Now your Solar Charge Controller should indicate both battery and panel have been connected. 

If you set up your system correctly and have good-quality equipment you probably won’t face such problems anymore. However, do note this is a guide for a simple system. If you have a much more complex system it is highly recommended you hire a good electrician to troubleshoot your system. 

Also along with this setup make sure your solar panel is getting good sunlight and not being shadowed by trees or other things. And weather conditions should be normal. 

Solar Charge Controller Troubleshoot. 

If your solar panel is showing a problem moon error symbol, zero power, frozen display, etc. it affects your battery charging. 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 resetting. 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 battery 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 panel is not charging the battery, so don’t forget it.


Batteries not being charged is very frustrating. Fortunately, it can be solved if you have proper knowledge of how to check and diagnose it, the reasons why this happens, and ways to fix it just like we discussed previously. Not only knowing it will solve your problem but it will prevent you from other future problems.

The Key Takeaways are- Faulty Solar panels, Broken Batteries, and Broken Equipment can cause the battery not to be charged. So take care of your equipment and don’t use low-quality products.

Wrong System Setup and Solar Charge Controller can also contribute to this problem. So be sure that your wiring is correct and if you suspect something is wrong with your charge controller reset it. It’s highly recommended you hire an electrician if your system is big and complex.

Overall, with proper care of the battery, panel, and other equipment, proper knowledge about the charging mechanism, and reasons for the problem you can easily solve such problems.