You have the power to prevent such nasty defects in the form of solar panel hot spots from occurring in the first place. In fact, it’s the greatest power of all. The power of choice. What may be less than expected selection criteria most definitely does not include the term Tier-1. 

Some would describe solar panel hot spot as insignificant blemishes which occur in common solar modules. Common is potentially a better word for cheap. Considering the information  you will discover below, you’ll be better equiped with the information to determine whether solar panel hotpot is insignificant or or a critical instability.

Hot Spot - Solar Review


The extreme side effects caused by solar panel hot spot will present some of the most devastating consequences for any system owner.


Hot Spot - Solar Review

A varied array of causes facilitate the solar panel hot spot effects to occur. Never fear as there are many things an end user can do to prevent such issues. Before prevention can successfully be achieved, it’s alway best to understand a little about the obvious causes without getting over technical.

Internal Damage.

Damage toward the internal components of the solar module is often a result of mishandling during manufacture, transportation or installation. Such internal damage can cause micro cracks and hot spots over time. 

Alternative internal failures can be a result of cell material defects, contamination, high circuit resistance, cell fractures, poor solder joints, local delimitation and more.

Cell Mismatch.

An occurrence by when cells of varying current are connected in series which can often be mitigated via the solar panels bypass diodes.Essentially, cells of higher current are trying to push more energy through other cells down the line which are of limited capacity.

None-the-less ensuring cells of equally matched current is essential to avoiding solar panel hot spot. 


Soiling is foreign matter resting directly on the surface of the solar module, obstructing the cell from direct rays of light. Surface fouling of is the most addressable issue to prevent solar panel micro cracks.

Frequent system maintenance will address common soiling issues. A comprehensive assessment of the proposed environment for the module installation should be performed in line with scheduled maintenance.


The effects of environmental impact can most certainly be lessened during the process of designing the system. 

The most common environmental factor which can cause hot spot is shading affecting the series circuit.  A detailed site evaluation should be done to ascertain the effects of objects that may shade the solar panel throughout the day and year. 

Weaker product selection for more extreme environments will also induce the effects of solar panel hot spot. To guide against such, it’s advised to study the environment before choosing the right module for the installation site. For instance, if the assessment reveals that such a location is prone to extreme winds and hail storms, solar panels that have been tried and tested to withstand such conditions must be selected.


As you will see, the side effects of solar panel hot spot range from minor through to extreme within only a few stages. 

Hot Spot - Solar Review

High Resistance.

In fact, the hot spot is now a visual effect of severely high levels of cell or circuit resistance. Resistance within a solar panel circuit is essentially the same as busy Freeway/ Highway at peak hour. Less resistance ensures the electrons can get where they need to go faster and ultimately work better for you, producing more power.


Many protective glass breakages are actually the result of solar panel hot spot and not impact. Glass is often very telling of where the shatter point occured. Once a solar module is shattered the system will likely shutdown as moisture begins to affect the electrical circuit. 

Earth Fault.

In most instances the solar panel hot spot itself doesn’t induce the earth fault (critical system failure).  Moisture penetrating the solar circuit does. A result after the solar panels protective layers have been damaged.


Could all the elements possibly align in which an insignificant hotspot combined with the associated side effects facilitate a fire? Absolutely. so much so that this is it’s own dedicated critical failure. Explained in more detail: Solar Panel Fires Exposed > (opens in a new tab)


Hot Spot - Solar Review

It really is this simple and where your ultimate power comes into play, choice. Understand that prevention of solar panel hot spot occurs on 2 levels: 

  1. Selecting a solar panel which doesn’t rely on the term Tier-1 in order to appeal.
  2. Selecting a reputable manufacturer endorsed solar installer.
Note: Selecting a technically trusted, manufacturer endorsed solar installer initially can often assist toward better solar panel selection and assurance.

Manufacturers with extensive Electroluminescence (EL) imaging procedures within the quality control chain ensure damage is arrested before a solar module is released to the field. Selecting a solar panel manufacturer with an esteemed reputation and excessive EL testing throughout the manufacturing process ensures the solar module you’ve selected remains hot spot free.

Installer. After selecting the right solar panel, it all hinges on the intelligent solar installer. The installers job is to advise on adverse factors which could affect a healthy solar panel operation, as listed in the causes section above. Reputable installers will always provide a maintenance and care package to assist in managing certain environmental factors which can cause solar panel hot spot in the future. As they say, prevention is the best cure!

DIY Hot Spot Detection: Infrared cameras are becoming widely available in multiple forms such as simple iPhone attachments. An IR image offers a fast and economical method for identifying more severe defects across the full site where several hot spots can show more extensive cell damage. 

Get vocal!

Got feedback or a question? Then leave it below in the comments section. The Solar Review community is super responsive.

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  1. The industry is constantly trying to make panels able to withstand the heat generated by partial shading. Bypass diodes do not prevent it; they only take that string out of service so it does not pull down the rest of the panel. But the string is still an active circuit, so the illuminated cells’ power is forced into the shaded cell, which is in reverse conduction. That power can only be shed as heat, thus causing a hot spot. The idealPV technology is the only panel that senses when a cell is about to be reverse biased and controls the output such that maximum power is held but no reverse conduction, hence no hot spot. So their panels is built with 240 quarter cells in one string, no bypass diode

  2. Are you familiar with IdealPV? They have a patent for solar panels that are free of hot spots. They prevent reverse bias from occurring. what is your opinion of this technology?
    Thank you,


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