Solar Panel Hot Spots Explained (Causes, Danger & Detection)

Hot spot basics: what one is

A hot spot is just what it sounds like: a small area of a panel that runs much hotter than the rest. It starts when one cell, or part of a cell, can't make power like its neighbors. It may be shaded, dirty, cracked or poorly connected. The other cells keep pushing power through it, and that weak cell turns the power into heat.

The rest of the panel keeps working, so a hot spot often shows no clear sign until it has done damage. That is why it is worth understanding. This post is part of our solar maintenance and repair guide.

Hot spot causes: shade, dirt and damage

Here are the common triggers, most frequent first:

• Partial shade. A branch, a vent pipe or even a stuck leaf shades a few cells. Those cells hold back the rest and heat up.
• Caked-on dirt. A patch of pollen, a lump of bird droppings or lichen blocks light just like shade does. That is the direct link between dirty panels and hot spots.
• Cracked or faulty cells. Tiny cracks from hail, heat stress or a factory flaw make spots where power struggles to flow.
• Bad connections. A loose or corroded joint inside the panel traps heat in one place.

You can prevent the first two with basic upkeep. That is the good news later in this article.

Hot spot dangers: lost power and fire risk

There are two reasons. One is about money, and one is about safety:

• Lost output. A cell that turns power into heat drags down the whole panel. It often drags down the string, which is the row of panels wired together with it.
• Damage and fire risk. Steady heat in one spot can discolor the panel and make its layers peel apart. It can also burn the backsheet (the plastic layer on the back) and crack the glass. In the worst cases, it can start a fire.

Left alone, a hot spot rarely heals. It tends to get worse, because the damage makes even more heat. That is why catching it early matters, and why it is on every good maintenance checklist.

Finding hot spots with thermal imaging

You usually can't see a hot spot with the naked eye, especially early on. The standard tool is thermal imaging, a camera that shows heat instead of light. A technician scans the panels, and a hot spot shows up as a bright patch on an otherwise even panel. Service Solar Pros pairs the thermal scan with test meters to confirm what the camera shows.

Some clues call for a scan, like one string making less power for no clear reason or a panel with a brown or scorched patch. If your Enphase or SolarEdge app shows one panel or section falling behind, a thermal check confirms the cause. Our guide on why solar panels stop producing covers the wider troubleshooting steps.

Fixing and preventing hot spots

The fix depends on the cause. If it is shade, have the branch trimmed or the object moved. If it is dirt, a professional solar panel cleaning often solves it. If a cell is cracked or an inside connection has failed, the panel usually needs to be replaced, because that damage can't be cleaned away.

Prevention is much easier than a fix. Keep the panels clean so no patch of dirt shades a cell. Keep trees trimmed as they grow, and get a yearly checkup with a thermal scan. A solar maintenance plan builds that scan into each scheduled visit.

If a panel does need replacing, our solar panel repair team can help with the warranty claim. Whether the panel maker covers it depends on its warranty terms and the cause of the damage.

Florida conditions: sun, dirt and heat

Central Florida sets up hot spots in more than one way. Our strong sun means panels already run hot, so a weak cell has less room to cope. Heavy pollen, spring and fall lovebug swarms and lots of birds leave patchy, caked-on dirt that shades cells. Afternoon storms and hail can also crack cells that turn into hot spots later.

So hot spots are more likely here than in a cool, dry climate. The good news is that the routine cleaning and checkups Florida panels need anyway are what stop them from forming.

Worried about a hot spot? Get it scanned

Is a string making less power, or have you seen a brown patch on a panel? Service Solar Pros will run a thermal scan, confirm the cause and fix it the right way with a cleaning, a trim or a new panel, for any brand and any installer. We serve Winter Garden, Leesburg and all of Central Florida. Book a thermal diagnostic, request a free quote or call (407) 270-2542.

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