Mighty Mule Solar Panel Not Charging | Reasons and Solutions

A dead battery, a faulty battery connection, melted fuses, or burned rectifiers can cause your Mighty Mule solar panel to not charge. It can be replaced. But, in all other cases, it is best to have the battery fixed by a professional.

Simply separate the solar panel wires from the control board and connect them directly to a dc voltmeter to test if the solar panel is charging or not. In direct sunshine, the panel output should be at least 18 volts dc at 300mA.

For a more comprehensive encounter with the issues and their fixes, let’s carry on up to the end.

Mighty Mule Solar Panel Not Charging

Why Is My Mighty Mule Solar Panel Not Charging the Battery

The reasons why your Mighty Mule solar panel isn’t working and the solutions to the problems are illustrated below:

1. A problem in Charging Circuit

The generation and collecting of light-generated carriers cause the short-circuit current in your Mighty Mule solar panel. The short-circuit current and the light-generated current are the same for a perfect solar cell with the most moderate resistive loss mechanisms.

IV curve of a solar cell showing the short-circuit current

Figure 1: IV curve of a solar cell showing the short-circuit current


Check for faulty equipment in the circuit and replace or fix it immediately.

2. Battery Capacity Problem

If the battery runs out even after properly charging it, use a battery with enough power to last a long time. The battery has a typical service life of two to three years. If your battery is more than three years old, it must be replaced. A malfunctioning battery might also be caused by a broken battery pack.


Contact your vendor and request a replacement of the faulty battery. You must ensure that there is enough sunlight for the battery to perform properly, as insufficient sunlight can cause it to malfunction.

3. Solar Charge Controller Problem

The solar charge controller could be defective or improperly wired. The system must be reset in this instance.


Resetting the solar charge controller returns it to its factory settings. It restores system voltage, output voltage, and other functions. Rewire the solar system after disconnecting it. To restore the factory settings, follow the on-screen instructions.

4. Electrical Issues

Faulty wiring impairs the performance of your Mighty Mule solar panels battery. Electricity output may be hampered by loose connections, corrosion, and oxidation. 


Do not attempt to mess with the wiring system unless you know what you’re doing or are a licensed electrician. Tampering with solar panel wiring is a crime in certain nations if you are not a licensed electrician. Contact a certified electrician to ensure that everything is in working order.

5. PID Effect

PID is an abbreviation for Potential Induced Degradation. It can happen as a result of a voltage mismatch between the earthing and the solar panel. When this occurs, the primary power circuit generates partial voltage discharge. 


The PID effect may reduce the efficiency and performance of the panels, as well as shorten their lifespan. Fortunately, a solar professional can assist in resolving or preventing the issue.

Is Mighty Mule Solar Battery Repairable?

No, you can’t repair a Mighty Mule solar battery. To retrieve it temporarily, in a glass of water, dissolve 3-4 teaspoons of baking soda. Then, using a cloth, clean the battery surface with the solution. Check the water level in each cell by removing the cover or caps from the battery’s cells. 


As you can see, the issue is almost always with the battery if your Mighty Mule solar panel isn’t charging. The majority of the time, this is due to an external hardware problem. Before changing the complete battery, it is critical to do a comprehensive inspection.

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