Ways To Tell If A Solar Panel Has Gone Bad

Solar panels can go bad for several reasons. I’ll outline several ways to tell if a solar panel has gone bad in the list below.

  • Insufficient Voltage and Current Output
  • Seebeck Voltage Reduction
  • Visible Physical Deterioration
  • Hotspots
  • Microcracks
  • Snail Trails
  • Broken Glass
  • Decade-old Solar Panels
  • Presence of Impurities
  • Poor Welding
  • Overheating

Keep reading through to learn more about protecting your solar setup for maximum longevity and performance, so stick around. Let’s dive in.

Solar Panel Gone Bad? Here’s How To Tell

When a solar panel has gone bad, it will not be as efficient in producing electricity. 

There are many ways to tell if a solar panel has gone bad. 

Insufficient Voltage and Current Output 

When the solar panel’s output does not measure up to at least 80% of the panel’s specifications and nominal rating, it may indicate something at fault. Measuring the production during noontime on a bright, sunny day is advised. Ensure the meter is set to at least a 10-amp scale to avoid damaging the meter when measuring the current.

Seebeck Voltage Reduction

The Seebeck voltage defines the direct conversion of temperature differences to electrical voltage. If it is low, the measured temperature will be low, too. It is not easy to notice, but it could generate too much temperature. As a result, the materials will be damaged and disrupt the process of generating electricity.

Visible Physical Deterioration

Once installed, solar panels get exposed to various elements that can cause physical deterioration. You can see this wear and tear through physical inspection. 


A hotspot occurs when a solar panel is in the shade, and the current cannot flow around weak cells. As a result, the currents are concentrated in a few cells, making them overheat and possibly even causing melting. 

Since the hotspot effect is a fire hazard, it is necessary to use bypass diodes to ensure that current can flow around weak cells even when shaded. Moreover, ensure that no trees or blockage may cause the shading to panels. 


Microcracks are also called microfractures, which can affect both energy output and the system lifetime of a solar photovoltaic system. I highly recommend proper handling because slight imperfections in the silicon cell can lead to larger micro cracks. 

Microcracks are often attributed to poor quality materials, incorrect handling and unsuitable transportation, thermal cycling, humidity, freezing, wind, snowfall, and hail. Drop, bump, or twist the modules during installation may result in microcracks.  

Identifying microcracks can be possible using the naked eye. However, several testing methods, such as electroluminescence (EL) or electroluminescence crack detection (ELCD), may help detect microcracks. When purchasing a solar panel, it is essential to ensure a trusted supplier to avoid the defective product.

Snail Trails

Snail trails are small dark brownish lines and discoloration of the panels, which may be a sign of deterioration and microcracks. Usually, these build up over a couple of years when moisture enters and diffuses the cell surface. 

With moisture, the silver from the grid contact fingers gets dissolved, and the silver ion migration to the EVA (Ethyl Vinyl Acetate) foil encapsulation can set in the snail trail formation. The snail trail can affect the modules when generating power by a 6% drop.

Broken Glass

The glass in the solar panel protects the solar cells and other delicate raw materials against water damage, harsh weather elements, and any other external danger. Since these are exposed to intense UV radiation and temperature variations daily, the glass may break off and need repair.

When there is broken glass, the solar panel will still work but not absorb light as efficiently. Generally, the performance may drop in proportion to the size of the damage. If there is a 10% broken solar cell, there will be an expected 10 to 20% drop in voltage output. You must replace the whole panel if the glass suffers a significant break. 

Decade-old Solar Panels

In general, the useful life of a solar panel is 25 years. It does not die right away but continues to produce electricity. However, as it ages, the output will significantly reduce. Once it reaches 20 years old, the electrical result may be less, and the panel may require further testing to see if it’s worth keeping in the system.

Presence of Impurities

Impurities like dust and dirt may get inside the panel during manufacture or installation. The impurities in thermocouples may make the deterioration faster. Once oxidation occurs, the currents carried across the sectional area will reduce.

Poor Welding

Poor welding can cause an open connection detected by a thermocouple check. It may even result in the breaking of the hot junction of the thermocouple. 

Even during installation, poor welding may result in an unstable array. Sudden strong wind may ruin the structure, leading to further damage.


Solar panels are exposed to extreme levels of humidity, extreme heat, and cold, ranging from 85 degrees Celsius to negative 40 degrees. Once it passes these intense tests, it is deemed ready for sale and installation. 

The solar panel may get too hot and overheat. When it happens, the efficiency drops drastically, losing lots of energy from the sun. Suppose you want to avoid panels from overheating. In that case, you must ensure good airflow to reduce exposure to moisture caused by humidity.

What Should You Check In A Solar Panel?

One of the most effective ways to know if the solar panel has gone bad is with a multimeter. It can measure open circuit voltage (Voc), short circuit current (ISC), and operating current.

So, how do you use the multimeter? Here are the step-by-step procedures:

Measure Open Circuit Voltage (Voc)

First, you need to locate the open circuit voltage (Voc) on the specs label and take note of the numbers. Then, plug the black probe into the COM terminal on your multimeter and the red probe into the voltage terminal.

If the voltage range is not auto-range, it is time to set the multimeter to the DC voltage setting. Bring the solar panel outside and place it in direct sunlight by angling it toward the sun.

Now, read the voltage on your multimeter and compare it to the open circuit voltage (Voc) indicated on the label. It should be close enough and does not have to be identical. If the voltage measurement is significantly less than the Voc, the solar panel might be damaged. 

Measure Short Circuit Current (ISC)

Identify the short circuit current in the label. Prepare the multimeter to measure amps by moving the red probe to the terminal. Set your multimeter to the amp setting.

Take the panel outside and put it in direct sunlight. Touch the multimeter’s red probe to the metal pin inside the positive MC4 connector. Then, touch the black probe to the metal pin inside the negative MC4 connector. A spark may occur, but this is normal.

Read the measurement and compare the label’s short circuit current (ISC). The measure must be close to the number indicated on the label. A higher difference means the solar panel has something wrong.

Measure Operating Current (aka PV Current)

The first step is to connect the solar charge controller to the battery and the adapter cables to the charge controller. Then, connect the negative solar cable to the negative adapter cable. 

Set the multimeter to measure amps. Turn the solar panels upside down or cover them so they won’t generate electricity.

Use the red multimeter probe to touch the metal pin on the male MC4 connector. Touch the black multimeter probe to the female MC4 connector.

Remove the covering and read the amperage. Compare with the specifications on the label. There may be a difference, but it should typically produce 70-80% of its rated power output.

Does a Solar Panel Go Bad If Not Used?

Solar panels do not expire but may still go bad when not used. However, it will naturally wear and tear when exposed to different weather conditions, water, and falling debris. It can weaken the efficiency of producing energy or may develop microcracks that will eventually damage the entire panel.

On average, solar panels have an average warranty of 25 years. With proper care and maintenance, solar panels may have a longer lifespan; some still work efficiently for over 30 years. Though they can slowly depreciate over time, the solar panel is a good investment.

The solar panel may fail because of several factors, such as:


Generally, solar panels made from high-quality and premium materials have a lesser chance of failing. Cheap raw materials may have rapid degradation. 

Panel Assembly

The array assembly defines its useful life as not all materials can work well together. Incompatible materials for the panel may accelerate degradation and will increase the amount of oxidation or voltage leak.


Proper handling and installation are critical to helping avoid damage as early as possible. Optimal angle and clamping can improve self-cleaning and mechanical resistance. 


Though solar panels may not be a high-maintenance product, it is essential to conduct regular monitoring to identify possible physical signs of deterioration. It will also help to schedule the removal of any build-up of dust or debris. Moreover, you can also detect loose cabling or shade and blockage that could affect the electricity output. 

Do Solar Panels Need To Be Cleaned?

Regular maintenance of solar panels can increase the lifespan of the unit. Over the years, dust, dirt, dirt, debris, and other impurities may accumulate. Solar panels need sunlight exposure to produce power.

In general, cleaning the solar panel is not necessary. Occasional rain is enough to wash off debris that can lower production. Suppose you reside somewhere with high smog, dust, dirt, or sand blowing around. In that case, periodic cleaning may help remove these and improve production.

Should You Remove Any Snow From Solar Panels?

Generally, snow in the solar panel will typically slide off on its own and does not require cleaning. Since most solar panels tile at an angle, the snow will slide off as it melts. 

Solar panels installed and stored horizontally may suffer weight damage from the snow that may break the glass. Hence, a solar panel snow rake makes it easy to remove snow safely. Do not use a standard broom, shovel, or other non-specialized tools to remove snow from the panels. It may scratch the delicate panel glass and lower your power production.

Can I Spray My Solar Panels With Water?

As suggested by experts, spraying solar panels with water may be done at least once a year. It may be tempting to hit with as much water as possible to get the job done quickly, but it is likely to create fine cracks on their surfaces. As a result, it may ruin the efficiency of the solar panels and invite future problems.

The best maintenance procedure is to sign up for a thorough panel cleaning service at least once yearly. Letting the professional handle the maintenance and cleaning of solar panels would help avoid future issues in the solar panel. Furthermore, it ensures maximum efficiency and savings from their solar power system.

Maintenance For Solar Panels

As long as the panel works according to the specification, homeowners may only need to conduct annual inspections and cleaning. It will help maximize the solar panels’ output and reduce repair and replacement costs.

However, keep looking for the voltage and current output as it may indicate fault. It is the first thing that shows something is faulty with the system. When there is a sudden drop in energy produced and electricity bills are rising, these may be the red flags indicating your panels require maintenance sooner than scheduled.

Solar energy is the most abundant source of clean energy on Earth, providing up to 10,000 times the total energy it needs. Solar panels capture the sun’s energy without burning fuel. It makes it a clean energy alternative source that can combat the current climate crisis and reduce our dependence on fossil fuels.

Why Is Solar Energy A Good Option?

Compared to other energy sources, I believe solar energy has many advantages. 

  • It is a 100% renewable energy resource.
  • Solar energy is free and available except in places where the sun doesn’t shine.
  • It does not need fuel, thereby saving money.
  • It does not emit harmful natural gasses or hazardous by-products.
  • Solar energy is silent and will not disturb others.
  • It helps reduce fossil fuels, so it does not harm the environment.
  • It is a reliable energy source, and even big corporations have adopted it.
  • Many regard it as the best measure against climate change.
  • It also generates wealth and local employment.

What Are The Downsides Of Solar Energy?

But, solar energy also has its downside, such as:

  • It requires an expensive large battery to store the generated power.
  • Some parts of the world can not fully utilize this energy because it depends on the number of hours with sunlight.
  • Solar panels may be an expensive investment.
  • Solar panel contains materials that may be toxic to health when improperly disposed of, so ensure you dispose of them properly.


Solar panels have minimal maintenance, and the possibility of going wrong is minimal. However, when the solar panel fails, the efficiency of energy output is significantly reduced. It does not allow you to maximize the investment. 

Solar panels may have a warranty lasting between 10 and 20 years, but some are as long as 25 years. However, these warranties may only cover if the units have regular maintenance systems. 

Solar panels will improve production with physical inspection, annual cleaning, and maintenance, reducing the cost of repairs and maintenance. But, this procedure must be handled with care or left to professionals to avoid future problems that will degrade the system. 

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