Most solar panel faults can be repaired without replacing your entire system.
A drop in output, an error code on your inverter, or visible damage to a panel does not automatically mean the whole system needs replacing. Solar panel repair covers a range of common issues, from cracked glass and hot spots to faulty wiring and failed bypass diodes.
The real question is whether repair makes financial sense compared to replacement. This guide walks through the most common solar panel faults, which ones are repairable, and when it is better to replace the affected panels entirely.
If your solar system is underperforming, contact the SolaXs team for a system health check. We service all brands on the Mid North Coast. You can also check out our Solar Care Plan for ongoing maintenance.
Common Solar Panel Faults That Need Repair
Solar panels have no moving parts, but they are exposed to weather, heat cycling, and wildlife for 25 years or more. Over that lifespan, several things can go wrong. The most common faults that trigger a solar panel repair call are related to the panel glass, the internal cell connections, or the junction box on the back of the panel. Most of these faults show up as reduced output on your monitoring app before any visible damage appears.
Here are the faults a CEC-accredited installer will check for:
- Cracked glass: caused by hail, fallen branches, or thermal stress. Small cracks may not affect output immediately but allow moisture in over time
- Hot spots: one area of the panel overheats due to a failed bypass diode, shading, or a cracked cell underneath. Visible as a brown or yellowed patch
- Bypass diode failure: each panel has 2-3 bypass diodes in the junction box. A failed diode can cut output by up to 33%
- Delamination: the protective layers separate from the cells, allowing moisture and air in. Usually visible as bubbling or discolouration
- Snail trails: dark lines across the panel surface caused by moisture reacting with silver paste in microcracks. Cosmetic at first, but can worsen
- Wiring and connector faults: loose MC4 connectors, chewed wiring (possums are the main culprit on the Mid North Coast), or corroded junction boxes
Not every fault means the panel is finished. A diode replacement takes under an hour. A cracked panel with stable output might run for years with a sealant patch. The decision depends on the type of damage and how much output has dropped.
Solar Panel Repair vs Replacement
The repair-or-replace decision comes down to three things: how much output the panel has lost, whether the fault will get worse, and whether the panel is still under warranty. A panel producing at 80% or more of its rated output with a minor fault is almost always worth repairing. A panel with widespread delamination or multiple cracked cells is better off replaced.
| Fault | Repair or replace? | Why |
|---|---|---|
| Single cracked cell, output stable | Repair | Seal the crack to prevent moisture ingress. Monitor output. |
| Bypass diode failure | Repair | Diode replacement restores full output. Quick and inexpensive. |
| Possum-chewed wiring | Repair | Rewire and install critter guard. Panel itself is fine. |
| Widespread delamination | Replace | Cannot be fixed in the field. Moisture damage is progressive. |
| Multiple hot spots across panel | Replace | Indicates widespread cell damage. Repair cost approaches replacement cost. |
| Shattered glass, cells exposed | Replace | Structural integrity is gone. No safe or lasting repair. |
| Snail trails (cosmetic only) | Monitor | No repair needed unless output drops. Recheck annually. |
A useful rule of thumb: if the repair cost is more than half the price of a new panel of equivalent wattage, replace it. New panels are more efficient than anything installed 10 years ago, so the upgrade often pays for itself in extra output.
What Does Solar Panel Repair Cost in Australia?
Solar panel repair costs vary depending on the fault, how many panels are affected, and whether the work is covered under warranty. A standard call-out and diagnosis from a CEC-accredited installer typically starts at $90 to $150 for the first hour. Simple repairs like a diode replacement or connector fix can often be completed within that call-out time.
Here is a rough guide to common repair costs:
- Bypass diode replacement: $80 to $200 per panel (parts and labour)
- Wiring repair or connector replacement: $100 to $250 depending on access
- Critter guard installation: $300 to $800 for a full array, depending on roof layout
- Single panel replacement: $200 to $500 for the panel, plus $100 to $200 for labour
- Inverter repair or replacement: $500 to $2,500 depending on brand, size, and whether it is a string or micro inverter
These are indicative figures. Your actual cost depends on roof access, system size, and whether the original installer is still in business. If they are not, any CEC-accredited installer can service the system.
Warranty check first: Most panels carry a 10 to 25-year product warranty from the manufacturer. If the fault is a manufacturing defect, the repair or replacement may be covered at no cost. Check your warranty documents before paying for a call-out.
How to Tell if Your Solar Panels Need Repair
The clearest sign is a drop in daily energy production that is not explained by weather or shading changes. If your system was producing 25 kWh per day in summer and has dropped to 18 kWh under similar conditions, something is wrong. Most modern inverters and monitoring apps (like the SolaXs monitoring portal) flag this automatically.
Other signs to watch for:
- An error code on your inverter display or app
- One panel producing significantly less than the others (visible on microinverter or optimiser monitoring)
- Visible damage: cracks, brown patches, bubbling, or discolouration on the panel surface
- Scorch marks or melting around the junction box on the back of the panel
- Tripped circuit breaker on the solar DC isolator
If you see scorch marks or smell burning near the junction box, switch off the system at the DC isolator immediately and call an installer. That is not a wait-and-see situation.
Can You Repair Solar Panels Yourself?
No. In Australia, all work on grid-connected solar systems must be performed by a licensed electrician, and the Australian Government recommends using a CEC-accredited installer specifically. Opening a junction box, replacing a diode, or rewiring connectors on a live solar array carries real electrical risk. Panels generate DC voltage whenever light hits them, and you cannot switch them off from the ground.
Beyond the safety issue, DIY repairs void your panel warranty and your installer workmanship warranty. If a DIY repair causes a fire or electrical fault, your home insurance may not cover the damage.
- All solar electrical work requires a licensed electrician in every Australian state
- CEC accreditation means the installer has solar-specific training beyond a standard electrical licence
- DIY repairs void manufacturer warranties
- Panels produce DC voltage whenever exposed to light and cannot be fully isolated on the roof
The only maintenance a homeowner should do is visual inspection from the ground and keeping the panels free of heavy debris. Everything else is a job for a qualified solar installer.
What Happens During a Professional Solar Panel Repair
A CEC-accredited installer will start with a full system inspection, not just the panel you flagged. They check inverter error logs, measure string voltages, and use thermal imaging to identify hot spots across the array. This matters because a single underperforming panel can drag down an entire string of panels wired in series.
The typical repair process:
- System isolation: the installer switches off the DC isolator and AC breaker before working on the array
- Visual inspection: checking every panel for cracks, discolouration, junction box damage, and wiring condition
- Electrical testing: measuring voltage and current on each string, then individual panels if a fault is found
- Thermal imaging: an infrared camera identifies hot spots that are not visible to the eye
- Repair or replacement: diode swap, connector repair, panel replacement, or wiring fix depending on the fault
- System recommission: the installer restores power and verifies output matches expected levels
The whole process takes 1 to 3 hours for a straightforward repair. Complex jobs involving multiple panels or inverter replacement may take longer.
Keep Your Solar System Running With Regular Maintenance
Most solar panel faults are easier and less expensive to fix when caught early. An annual inspection by a CEC-accredited installer picks up problems like loose connectors, early-stage delamination, and possum damage before they cause significant output loss. On the Mid North Coast, salt spray, heat cycling, and wildlife are the biggest threats to panel longevity.
SolaXs offers a Solar Care Plan that includes regular inspections, cleaning, and priority service if something goes wrong. If your system is showing signs of reduced output, or you just want a professional check after a few years, get in touch with the team to book a system health check.