What are Solar Hotspots? Bypass Diodes, Cells, & Strings⚡NSW

What are Solar Hotspots?

In addition to obvious signs of solar panel damage like cracked glass or dinted frames, there’s an invisible sign of damage called a solar panel hot spot.

A solar hot spot is a spot of concentrated heating of an individual solar cell, which can be caused by partial shading, debris, dirt, hail, aging, or manufacturer defects of internal components.

Older and cheaper systems are mostly affected as they are more susceptible to degradation and imperfections that will negatively impact the entire solar generation performance.

Each solar (PV) panel is made up of a series of solar cells, connected in a chain that individually generate voltage from sun exposure through the photovoltaic process. The overall panel's performance can be affected if chains are compromised by a hotspot.

What Causes Solar Hotspots?

Hotspots can be caused by a variety of reasons, from panel aging, harsh weather conditions, defects, and other compromising events.

When a solar photovoltaic (PV) cell is faulty or shaded by a tree, chimney or other obstruction, it produces less current than the other cells and is made to transfer the same current as the other cells. Because the shaded cells can’t generate the same energy output, it essentially becomes a resistor and dissipates heat, creating a hot spot.

Whilst some hotspots are minor, more extreme hotspots will greatly reduce your system performance, and can be a serious safety issue and should be checked by a professional immediately.

It's also important to note that new solar panels consist of modern technology to avoid hotspots, and quality solar installers will design and install systems to avoid shading as best as possible. Partial shading can also be more damaging to solar systems than full shade coverage.

Can Hot Spots Damage Solar Panels?

In addition to energy loss, there are additional ways that hot spots can cause damage to solar panels, including thermal expansion and stress due the constant heating and cooling, microcracks, panel delamination, or even burns and fires in extreme cases.

Solar panel hotspots can also cause internal damage to wiring and connector components which could further increase safety issues dramatically, especially if the panel bypass diodes are compromised.

Hotspots that are not taken care of can lead to greatly reduced performance and longevity.

How to Avoid Solar Hotspots?

To avoid and minimise the risk of getting hotspots on your solar panels, we highly recommend investing in high-quality solar panels and installer to ensure your system is designed for longevity and durability. Here are ways to avoid and minimise hotspot risk:

Choose quality panels: Solar panels of high-quality ensures your system is ready for longevity and is durable to withstand Australian conditions. It also confirms that internal components are free of imperfections that could eventuate into issues.

Invest in a Reputable Installer: Good-quality solar installers will install systems to Australian and manufacturer standards to maintain that your system be covered under warranty and that your system will be safely designed and installed to be long-lasting.

Monitoring & Maintenance: By regularly monitoring your solar system performance, you’ll be able to identify when your system is under-performing due to system-related issues. You can also book in a solar health check to get a thermal analysis of your system to search for hotspots.

How do Solar Panel Cells & Strings work?

A ‘string’ in a solar panel is the section of cells that are connected in a chain. (Refer to the green line). Think of it like how Christmas lights are chained on along the same ‘string’.

These string accumulate voltage and contribute to the output of the panel. When a string/substring is obstructed, it can cause that string to underperform and reduce the output of your panel. This is where Bypass Diodes come in.

Can you Fix a Solar Hot Spot?

Depending on what is causing your solar panel to have hotspots, you may or not be able to fix them.

If your panel simply has bird droppings on the surface, it could cause a hotspot but is easily fixed with a quick clean. If your panel has hotspots due to internal imperfections or other uncontrollable events, there unfortunately isn't a recommended way to fix the hotspots and most usually just opt for a solar panel replacement.

Depending on the age of your system, your panels might not be CEC-approved or manufactured anymore, which may mean you’ll need to either deal with reduced performance or replace your entire system. Sometimes a hotspot doesn’t directly reflect the panels health as they may be in decent condition.

It’s generally better to avoid solar hotspots rather than try fix them.

How to Identify a Solar Panel Hotspot?

To identify a solar hotspot, you can either book a health check, do a DIY thermal check, or analyse your production data and compare analytics.

Booking a solar health check: Depending on your local solar installer, they might provide solar health check services where they come out to your property to check your solar system for any issues. Elements like electrical health are checked, as well as visual inspections to ensure safety and compliance.

DIY Analysis: Another way you can identify solar panel hotspots is using your own thermal imaging to check the panels for any out-of-the-ordinary heat signatures. Here, you can also check for any dirt or debris and identify if the panels need cleaning. If you choose this route, we recommend doing so safely.

Performance Analysis: Another way to find if there are any obvious issues with your panels is to check your monitoring data and performance. Using this, you can compare yearly generation and determine if your system is underperforming.