Solar Panel Low Short Circuit Current: Reason and Fix

Many times people measure short circuit current and faces quite a common problem. The Short Circuit is too low. So why does this occur and how do you fix it?

Low Short Circuit Current issue is quite similar to Low Amp issues. There are generally three main causes, Environmental factors like Solar Panel Orientation, Internal Problems in Solar Panels like blown bypass diode, or Wrong Measuring method. 

Resolving these issues is fairly simple and can be done yourself or by taking help from experts.

Let’s talk about short circuit current. The voltage across your solar cell will always be zero by definition of short circuit. That means your positive cable and the negative cable are connected to each other.

Now before we move on to reasons and solutions to low short circuit current you should keep a couple of things in mind. Firstly, you have to understand and measure short circuit current properly, and Secondly, take proper precautions when dealing with electrical equipment.

Now that we are good, we will be discussing reasons and solutions to low short circuit current in detail below:

What is a Short Circuit Current (In Solar Panel)?

You probably know this already but it doesn’t hurt to clear up the definitions. Sometimes it helps you learn new things that will clear up your confusion regarding various issues.

If you learned about basic electronics in Physics we all know Current flows from High Voltage to Low Voltage in a circuit. There is a resistance (like a battery) in a circuit. 

And here we have a short circuit current. When the electricity flows in an unintended path with the least resistance. For example, take your solar panel. Connect its positive and negative terminal and you get yourself a short circuit. 

There are many factors in play that influence this Short Circuit current. Area of the Solar Cell, The Light it gets, optical properties, etc.

Now many will ask, Why is short circuit current important? First of all, all panels have a short circuit current rating. It basically indicates how much fault current your equipment can withstand. 

So measuring short circuit current will help you take optimal protection for your system.

How to Measure Short Circuit Current in a Solar Panel?

The first thing here to keep in mind is to use a clamp meter. Clamp meter will make measuring Solar Panel Short Circuit Current very easy and you will have less error to worry about.

 Also, Do Not attempt to measure the short circuit current of a whole array or high voltage panels! It’s way too dangerous!

Here are the proper steps:

  • Step 1: Make sure your panel is low volt. Under 100V you won’t have to worry about shorting connection. If you are working with high voltage it’s better to leave the measurements to professionals.
  • Step 2: Take the negative and the positive terminal in your hand.
  • Step 3: Short the connection by connecting them. There may be a spark but if it is low voltage it won’t harm you.
  • Step 4: Make sure your panel is perpendicular to the sunlight. In easy words, your panels should be getting proper sunlight.
  • Step 5: Take your clamp meter and set it to DC Amp
  • Step 6: Put the clamp meter on the shorted cable and you will get your short circuit current measurement.

Reasons For Low Short Circuit Current in Solar Panel

To pinpoint the reasons first we have to learn which factors decide how much short circuit current you will get from your panel. 

Area of the Solar Cell, number of photons (Small Particles of Light), incident light’s spectrum, optical and collection probability. 

If we analyze these things properly, we will find three main factors that cause low short circuit current in a solar panel. Those are-

  1. Environmental Factors
  2. Solar Panel Factors
  3. Wrong Measuring Method

Below we will be discussing them in greater detail

Environmental Factor

The most common reason low short circuit current issues happen is when your panel doesn’t get the proper amount of light.

 As said earlier, photon, the particle of light is a big factor in short circuit current; shortage of light will automatically give you a low amount of short circuit current.

And Environmental Factor plays a key part in it. We all know without light you will get low current. Think about it and you will soon find a lot of factors that stop panels from getting a proper amount of light.

Let’s start with shading. Let’s say a portion of your panel gets shadowed. Now what? That part won’t be producing current. And it would lead to chain affecting other parts too. 

And this will ultimately result in a dramatic loss of current.

And speaking of shading, don’t forget a lot of materials accumulate into your panel. For example, snow, dirt leaves and etc. These things also result in loss of current.

And now to the orientation of your panel. If not set up at a proper angle your panel won’t receive the proper amount of sunlight. 

As we discussed earlier, photon absorption is actually one of the most important factors in producing current. Thus if your panel doesn’t face the sun properly it won’t be producing current properly.

Now to Weather, extreme weather conditions affect all PV systems. Overcast Sky or Places with low sunlight will always affect current production. A clear sky with full sunlight with moderate temperature is the ideal condition for a solar panel.

Solar Panel Problems

If your orientation and environment are ideal then you should take a look at the panel itself. A busted panel will surely result in a low short circuit current.

The main Solar Panel problem that affects current production heavily is the broken bypass diode. It’s a small piece of equipment but a broken or bad bypass diode will turn your short circuit current one-third of what you should be getting. 

Now with the diode done, check your panel’s MC4 connectors. These are essential for conducting current. If you by any chance have a loose MC4 connector you will be getting low short circuit current reading.

Same with the junction box panel. Check if your junction box is wired properly. Otherwise, various critical systems of your solar panel will fail to provide you with a good current.  

Wrong Measuring Method

One thing people ignore is they use a completely wrong way to measure. And the result is unrealistic results/ You need to be very careful while measuring short circuit current. So make sure you know how to measure current properly.

From messing up the terminal, setting up the wrong values, and not using equipment properly, or even using broken meters will result in the wrong measurements. 

Also having magnets and things that produce magnetic fields nearby messes up the reading of the clamp-on meter.

Solutions for Low Short Circuit Current in Solar Panel

Now that we have learned about various reasons for this issue, it’s time we move on to troubleshooting. Troubleshooting most of these problems is quite easy and can be done by yourself.

More about these are discussed below:

Solutions to Environmental Problems that Causes Low Short Circuit Current in Solar Panel 

First, you have to make sure you have solar panels that support a variety of weather. Your panel should be able to handle a wide spectrum of temperatures so it will not malfunction in bad weather and give you low current reading. 

Now while testing short circuit current make sure your solar panel is not being shaded by nearby trees, shed, roofs, or any other thing. Otherwise, your short circuit current would plummet.

Also before your test, don’t forget to clean your solar panel. Accumulated materials on a solar cell will mess up short circuit current output. 

And finally the orientation. Your panel should be at 90 Degree (Right Angle) with the incident light while testing. In a simple world, sunlight should hit the panel in a perpendicular manner. 

And if you are in the northern hemisphere your panel should be facing south. 

Solutions to Solar Panel Issues

First talk about the loose MC4 connectors. Take a screw and loosen up the back gland. Then push the MC4 connector in and you’ll hear a click sound. And for a loose junction box, open it up and try fixing any loose components if you are confident otherwise seek help from experienced people.

Another thing you have to make sure of is if one of your solar cells is busted. Take a cardboard cover and use it to cover one solar cell in the panel. Now check the current. 

Repeat this for each of the cells. If during the experiment for one cell the current doesn’t drop that solar cell is busted and your solar panel needs replacement.

Now to bypass diodes. Replacing Diodes can be done yourself. But it’s only recommended if you know your ways with electrical equipment. Otherwise, seek help from professionals.

Here are the steps you can take to successfully replace a diode in the solar panel:

  • Step 1: First open the junction box (On the back of the panel). Use a small slotted screwdriver to pry it open
  • Step 2: Remove the diode. Under the lead of the diode use the tip of the solder iron. Then lift each lead of the diode separately.
  • Step 3: Make sure there are no excess solder in the hole of the junction box
  • Step 4: Take the new diode and bend its lead on U shape (Just like the one you took off) if it’s not pre-bended. Use pliers if necessary.  
  • Step 5: Install the diode on the terminal. The Gray bar of the diode should be facing the same direction as the (+) positive cable gland.
  • Step 6: Now you have to solder the intersection of the terminal and diode lead. Be cautious and do it safely.
  • Step 7: Close the Junction box and make sure it’s locked tight.

And you that you will replace your broken diode successfully.

Solution to Wrong Measuring Method

If you are using Clamp Meter (Which you should be) get the basics right. Set clamp-on meter to DC Amp. Short Circuit the panel properly. (I’ll say this again only attempt to measure the short circuit current of low voltage panel, do not attempt it on high voltage ones). 

Make sure the wire goes through the hole made by the teeth. And for the love of God, do not use a broken or low-quality clamp-on meter.

Now that we have got the basics covered let’s move on to other issues you must take care of. The panel should be perpendicular to sunlight. And there should be no magnet nearby as it will mess up the clamp on the meter reading. 


While testing short circuit current it’s natural to face this problem. Low Short Circuit current means something is wrong with your panel or the environment you are testing it in. Measuring Errors are rare but keep caution while measuring

To sum it up, Low Short circuit current can either happen if your solar panel is not getting sunlight properly or something is broken with the panel like diodes or loose mc4 connector. Always make sure your panel is getting proper sunlight and the components of the panel are in good condition. And you’ll not face low short circuit current anymore.