Solar panel repairs are the thing I get asked about most, and the question is nearly always the same. Is it worth fixing, or am I better off replacing the whole lot?
There is no single answer to that, and you cannot get to one from a price.
We went out to a home at Nambour recently to look at a system that was not performing the way it should. It is a good one to walk through, because the way you work these out is much the same every time.
Solar panel fault finding: we find out what is wrong before we talk about money
An underperforming system can have any number of causes, and most of them look identical from the ground. The panels sit up there looking perfectly fine.
Before I talk about what anything costs, I test the system. What that involves depends on what we are chasing. It will usually be a meter at the inverter and at the array, and on some jobs a thermal camera over the panels as well, so we both know what we are actually dealing with.
At Nambour I went over the array with a thermal imaging camera. Panels run warm in the sun, so heat on its own means nothing. What we are looking for is the difference, where one panel or one cell is running hotter than the ones around it. A failed cell or a bad connection has to push current through resistance, and that shows up as heat long before anything shows on the surface. It also has to be done in decent sun with the system running, because on a dull or windy day the differences wash out and a clean scan does not prove much.
Then it is the multimeter. We test at the inverter and at the array, and compare what is actually coming in against what should be. Between the camera and the meter you can usually narrow the problem down to one of four things: a single panel, a string, a connection, or the inverter itself.
That matters, because those four things cost very different amounts to put right.
Common solar panel faults on older systems
In my experience the inverter is usually the first thing to go. It works harder than anything else in the system and it is the part with the electronics in it. Ones mounted in full western sun tend to have a shorter life than ones sitting in the shade.
Close behind are the connections. Rooftop isolators and junction boxes sit out in the Queensland sun for years, and the plastic eventually gives up. A cracked enclosure lets water into a circuit that is live whenever the sun is up. Rooftop DC isolators were required on Australian installs until the rule changed in 2022, so most systems around here still have one sitting in the weather, and on an older system it is one of the first things I want eyes on.
Panels themselves can degrade too. The clear layer over the cells breaks down slowly in the sun, and you will sometimes see browning or discolouration as a result. It is usually a smaller loss than it looks like it should be. What matters more is the pattern. Browning spread fairly evenly across a panel is usually just age, while one cell noticeably darker than its neighbours is worth a closer look, because it can mean that cell is running hotter.
And then there is the one that catches a lot of people out, which is simply that trees grow. A system designed for a clear roof in 2013 may be sitting in afternoon shade by now, and nothing is wrong with it at all.
When a solar panel repair is the right call
If the array is sound and the fault is one component, repair it. Replacing an inverter, a run of cable or an isolator on an otherwise healthy system is usually straightforward work, and usually a fraction of the cost of a new system.
Before you pay anyone to replace an inverter, it is worth digging out your original paperwork and checking the date. Inverters often carry a warranty of five to ten years, and panels usually carry a longer product warranty again, so if the system is younger than you think the part may still be covered.
The same goes for a single failed panel, provided we can still match it closely enough on output and size. That gets harder as a system ages, because panel models come and go. A like for like swap is a straightforward repair. If nothing matches and the array has to be rearranged, it can count as an alteration rather than a repair, which brings other parts of the system up to current standards and changes the sums.
If you have been told the whole system needs replacing, it is reasonable to ask what testing that was based on. A fault is worth finding either way.
When solar panel replacement makes more sense
At some point the money spent keeping an old system going is better put toward a new one.
Usually it is one of three things. The system is too small for what the household now uses. There is no storage, so whatever you are not using at the time it is generated goes out to the grid for a feed in payment that is usually well below what you pay to buy that power back in the evening. Or the switchboard is not built to carry anything more, so any upgrade means that work anyway.
When two or three of those are true at once, replacing is generally the better spend. On an older system that is otherwise healthy, adding a battery to what you already have is sometimes worth pricing alongside a full replacement.
I will tell you which camp you are in once I have looked at it, and sometimes the answer is that your system is fine and you do not need me at all.
Four things you can check before you call anyone
Check the system is actually switched on. After a storm, a power outage or other electrical work, the solar supply main switch or an RCD at the switchboard can trip, and that often goes unnoticed for weeks. If you are at the switchboard anyway, take a photo of it, because I will usually ask you for one.
Have a look at your inverter display or app. Most will show a fault code or a warning light, and that alone tells us a great deal before we arrive. It also helps to know what time of day the output drops off. A system that is fine in the morning and poor by mid afternoon points somewhere different to one that never wakes up properly.
Compare this quarter’s bill to the same quarter last year rather than to last quarter, so you are comparing like seasons.
Look at the roof in the middle of the afternoon and check whether anything is shading the panels that was not there a few years ago.
And please do not get up on the roof yourself. The panels make voltage whenever light hits them, and switching the system off at the isolator does not change that. The bigger risk is usually simpler though. People come off roofs, and you can crack a panel just by standing on it. If something up there needs a look, give me a ring and I will go up.
Solar panel repairs across the Sunshine Coast
We are a local solar company based in Caloundra, and we repair and service solar across the Coast, including Noosa, Buderim, Caloundra, Mooloolaba, Maroochydore and Currimundi.
If your system is not doing what it used to, I am more than happy to come and test it properly and tell you honestly what it needs. If that turns out to be a repair, we will repair it. If you would rather look at replacing an older system, we do that too.
You can request a quote here, or please don’t hesitate to call or email.
Justin Zerna
Owner, AHJ Trade Services
0492 910 232
justin@ahjtrade.com.au
