Low Amp In Solar Panel: Causes And Fixes

Low amps or current is one of the most common problems you will face if you are running a solar system. You are literally getting low power output. Why?

Low amps in Solar Panels can happen if your solar panels fails to convert the sunlight into energy properly. One of the main reasons for inefficient power conversion is PWM Charge Controllers. Easy Solution to this is to use a way more efficient MPPT Charge Controller. Aside from that Environmental issues like Shading, Bad Weather and Wiring Errors also results in Low Amps.

The first thing to notice in this case is charge controllers. Solar Charge Controller controls the current as the name suggests. Some PWM controllers are not efficient at all. So this results into low amps. But the amps are not that low at all.

If your amps are extremely low there is a chance your panel is not getting proper sunlight. Take for example an overcast day. Your Panels won’t be getting any sun.

Other reasons include, Setup like Open Circuit, bad connection, messing up series and parallel setup that will sometimes cause problem like this. Along with that Equipment failures, like Diode Failure, Loose MC4 terminal will also cause low amp.

To understand why your panel  is producing low amp and ways you can fix them and even more increase your output you need to thoroughly understand the reasons of the problems in detail. In the following article we will be discussing what amps should your solar panel produce, reasons for low amp in solar panel, solutions to those issues and tips on increasing amp.

What Amps Should Your Panels Produce?

To understand what amp your panel should produce, first you have to measure the voltage and the amp of your panel. It’s rather easy.

Put your Solar Panel into Sunlight and make sure your circuit is properly connect. Now connect you multimeter in series, set parameter to DC Amp and measure the amp. Now connect your multimeter in parallel, set parameter to DC Volt and measure the volt.

Now look at the back of your panel. It should have a watt rating. Now we can calculate what amp your panels should be producing. Remember your high school physics book. Watt equals to Voltage multiplied by Amp.

The Equation is: Watt = Volt x Amp.
From here we can get: Amp = Watt / Volt (Watt divided by Voltage)

Now divide your panel’s watt rating by the voltage you measured. That’s what your Solar Panels should produce. 

For example: Let’s say you have a 200 watt panel. And you measure it’s voltage as 27.6. Then your panel should be producing around (200/27.6) = 7.25 Amps. It can be a little lower due to various conditions but not very much.

Reasons for Low Amps in Solar Panel

The main reasons can be divided into four parts. Most commonly, Using PWM Charge Controller, Environmental Issues like Shading, Bad Weather, High Temperature, Setup errors like bad connection, open circuit and Equipment Error like broken diode in panel, loose connector etc. 

We’ll be discussing these problem in detail below: 

PWM Solar Charge Controller

What is a Solar Charge Controller? As the name suggest it is an equipment that controls how much charge should go into your system. Without it your system would be fried and have a lot of accident. So it is an essential in every solar-based system.

Now there are two type of Solar Charge Controllers. First is the inefficient and low budget PWM (Pulse Width Modulator). And the second is the more efficient MPPT (Maximum Power Point Tracking) but costly charge controller.

So how does PWM Work? It basically slowly reduce the power as the battery is near full capacity. When your battery becomes full the charge controller provide tiny amount of power like trickling salt. So where does the problem occur?

PWM Controller need matching voltage between battery and the panel. Otherwise it doesn’t work properly. And this is what exactly happens in big circuits like if a solar panel is powering your home. 

In such large solar panel system the voltage varies a lot and as a result you get low amp in such situation if you are using a PWM Solar Charge Controller. MPPT on the Other hand perform very well despite being a bit more costly. 

Environmental Issues

There are a couple or environmental issues that seriously affect solar panel efficiencies. Think about it, your panel producing power depends on the sun if that gets disrupted you will see bad result. All PV systems are also dependent on surroundings.

Let’s talk about temperature. We know temperature effects current flow. Many people think High Temperature means Solar panels producing more power. That’s a big mistake. Solar Panel actually work good in cold weather. 

High Temperature can temporarily increase power output but it reduces voltage. In the long run high temperature can make your panel lose efficiency thus you will lose your amps.

Shading is also a big issue in Solar Panel if a portion of you panel get shadowed you will get significantly low voltage? Why? 

Because that shadowed PV Cells won’t be receiving sunlight and become non-functioning. Which in turn leads to many other same not function properly. This will result in dramatic amp loss.

Speaking about shading, materials accumulating into the panel also causes the same issue. Example can be snow, dirt, leaves and other things accumulating in your panel.   

Orientation is also a big factor. Your panel functions on light. If you put it on wrong angle it won’t be able to absorb light from Sun properly and will result in low amp. Sometimes light absorption also depends on Solar Insolation (Radiation of Sun that coming to Earth). It depends on sun’s position in sky, day length, pollution and other environmental factor. 

Setup Error

Another big problem regarding low amp is various setup errors. One of the main culprit is open circuit means flawed circuit. If something is open in a parallel circuit total circuit resistance increases. And high resistance equals to low amp.

Other problems are messing up parallel and series connections. Forgetting to connect crucial parts of the circuit. Physical damage to Wire. Using low quality safety equipment in circuit, etc. If there are errors in setting up your circuit you are bound to face low amp or even in some case zero amps.

Broken Equipment

The classic. Maybe you have top quality charge controllers, professionally wired system and no environmental issues. Well a broken equipment in the system will cripple your amp production.

Let’s take a simple diode in your panel. If it is busted it can send your amp production to one third of its former self. That’s how critical simple equipment and components are in a solar panel. 

The most common problem people face with Panel are aforementioned diode problem, loose MC4 connectors and a loose junction box. If MC4 terminals are loose and makes partial contact most current won’t be conducted properly and you will end up with low amp.

Bad Junction box in panel will cripple your panel as it won’t be able to transfer current properly and if bypass diode fails your power output falls likewise.

Other than that broken anything in any equipment would cause problem. And remember cheap low quality product and old equipment are the ones that are most likely broken.

Fixes for Low Amp in Solar Panel

Now that we know why this problem occurs it’s time to fix them. The solutions are fairly simple and hopefully they will be enough to troubleshoot your problems. In below we will be discussing in detail how can you fix low Amp in Solar Panel

Use MPPT Charge Controller

As said earlier PWM charge controllers are quite efficient due to its simple mechanism. On the other hand MPPT (Maximum Power Point Tracking) employs a complex mechanism that ensures you have the maximum power. How?

MPPT Charge Controllers has the ability to match non-matching voltage between the panel and battery. Also they can adjust their input so that you get the maximum power. And like this you get more efficiency thus more amp than PWM

MPPT Charge Controllers may cost more but in complex and large systems involving solar panels it is a must. Otherwise if you use PWM in such situation you will get low amp output. So if you are suffering from low amp consider buying a MPPT Charge Controller

Fix to Environmental Factor

First thing first in warmer climate your solar panels will get hot and cause low amp. So you want to ensure sufficient airflow to keep it cool. 

What you can do is to install panel few inches above the roof. You can also use solar panel made out of light colored material to combat heat absorption. And don’t forget to move inverter and combiners into a shaded area.

Now to shading. Always make sure to place your solar panel where there will be no possible shade. If there are things that are shading it consider removing them or moving you panel elsewhere. 

Make sure your panels remains clean. Shading can be devastating to amp output. To mitigate it’s damage consider using bypass diodes and micro-inverters.  

And make sure your solar panels face south if you are in northern-hemisphere. Also be sure to adjust your solar panel’s orientation four or five times annually.  

Fixes For Setup Error

The Best Solution is to hire an electrician and professionally wire your circuit. Unless you are experienced with electronics it’s highly recommended you do not attempt to troubleshoot the circuit. With that said and done you can take some steps to avoid setup errors:

  1. Always use good quality equipment, wires and panels. Using Old Equipment or Low Quality products are the main culprit in causing Setup Error.
  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 wire gets torn, etc. Always be super careful while wiring and don’t mess up terminal.
  3. Check for Bad Connection. Use multimeter to check voltage and various points and troubleshoot errors accordingly.
  4. Look for physical damage in the circuit. Sometimes wires get torn. To solve physical damage take protective measures from things that can harm your system.

Fixes for Broken Equipment

If your bypass diode is broken, ask your Solar Panel Company support to send a compatible replacement. Bypass diode can replaced easily.

In case of Loose MC4 connector take a screw and loosen up the back gland. And push the MC4 connector in so that you get a click sound. 

Hopefully this will solve Loose Connector. For junction box you can open it up and try fixing any loose component yourself. But it’s recommended that you take help from expert.

In other Equipment failure case you might have to replace it or hire electrician to fix it. And as always remember to use quality product. Using low quality product or old product will often result in complication like low amps. 


Low amp is a very annoying and common problem. Not only does it waste your time but it creates problem in your energy generation. So it should be fixed immediately. If low amp is not fixed your panel will face other problems too.

The key part here is to know what your panel amp should be, professionally wiring your circuit, using more efficient MPPT Charge Controllers, taking measure to prevent environmental problems and replacing and fixing broken components. 

With sufficient knowledge and protective measure you will be able to solve low amps in your panel. Hopefully this guide was able to answer most of your questions regarding Low Amp problem in Solar Panel.