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Home Solar System Servicing

I’ve had my home solar system for 8 years now & have heard of people getting much better output from their Solar Panels after upgrading their Inverter & I want to get my solar system serviced by someone who actually knows what they’re doing & not just trying to sell me something.
What do I need to look for (accreditation, etc.) when contracting such a service?

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Before you rush into installing a new inverter, hearing about others getting more output isn’t necessarily a good thing on which to base a decision.

Do these other installations have the same orientation, same PV array size, identical amount of shading ( a small amount can make a huge difference), same amount of clipping due to mismatch of inverter and panels, same amount of lost output due to high grid voltage etc?

Do you have any system monitoring?

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Newer inverters may have marginally better efficiency than older inverters, but the cost to replace an inverter with a newer one is unlikely to pay for itself over the life of the inverter.

Solar panel output won’t change, it will stay the same. As outlined above, a slightly more efficient (less losses) inverter may marginally increase inverter output, but the slight increase is unlikely to he noticeable or viable.

If one keeps their panels clean, then this is likely to have a better impact than upgrading an inverter. Cleaning is possible to do oneself if one knows what they are doing and it is safe to do so. Annual cleaning by a specialist (paid service) is unlikely to be cost effective unless one has a very large system with very dirty panels…or a flock of birds has decided to use the panels as a night roost.

The other consideration is you may be on higher feed in tarriffs which were offered more then 5 years ago and depending on the upgrade, this may mean one loses these generous FITs…and the FITs will revert back to the current levels being offerred. There is also a risk that if the local network has reached capacity from solar feed in, the network operator may refuse the upgraded inverter (if it has a higher output capacity) or restrict output to that which currently occurs. This means that you may be worse off in the long run from any upgrades.

There may be better (maybe still hot financially viable) to replace very old panels with new ones, if there as been a significant degradation in panel output due to their age. Without basic monitoring, one won’t know if this is the case and there is a risk one may be wasting money by making such changes.

I agree and it may be ‘wishful thinking’ or ‘sales spin’.

Usually the best time financially to change an inverter (like for like maximum output) is when the current inverter dies.

Edit: the other scenario where an upgrade may be viable is if one say has a 6kW inverter and only has 5kW of panels. Leaving the existing inverter, it may be possible to add 1-2kW more panels to maximise inverter outputs. One needs to check if there are any implications with exports (usually inverter outpur capacity is used for local distribution network assessment, not the panel outputs).

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No intention of spending money on the experiences of other novices that’s why I want to get my system serviced & appraised by a professional in the field.
My principal question was ‘what to look for’ in a solar servicing technician to ensure their professionalism?

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Is there a problem with your current setup?
Have you noticed a significant decrease in system output?
Are your panels very dirty or inaccessible?
Is your system small and you think you need a bigger one?

These questions should be answered before deciding on whether something needs to be done.

Otherwise an installer/service company will likely second guess what your problem is and find a solution which may not be in your best interests. Most members on this forum wouldn’t want to see this happen and why we ask probing questions to find out what issues may lie ahead.

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We’ve installed two solar PV systems in the previous two years. Different installers and systems. Neither installer suggested there was any need for annual servicing. There are no serviceable components. The PV panels may need cleaning was the only advice. Similar to giving the car a quick wash.

The question I’d ask is on what basis do solar PV systems require servicing? It sounds like a scam to me. Solar PV are not cars with at least annual servicing needs, or home air conditioning which might need a simple owner clean each year and performance check every 5 years.

As @gordon asked, do you have any monitoring of your solar PV? Our inverters provide basic data on the main control panel display. It’s enough to know in the first year the system at home provided 7,000kWh of generation. At the end of year two, assuming all Is similar we’d expect another 7,000 +/-5% or a progressive total of 14,000kWh from new. While many of us can look at more detailed monitoring data, it does not need to be complex to know our system is doing the job. Tracking weekly or daily output would be great if you are concerned.

Your comment about others getting much improved output by upgrading the inverter is most odd. Perhaps you can share details of your inverter brand, model, age and PV panel capacity. There are several community members who are experienced with PV. I’m confident someone will be able to respond.

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It is not unheard of to get major investments serviced from time to time to ensure everything is operating as it should. Perhaps if I had been logging data as diligently as a rain gauge I could answer these probing questions, but I haven’t & I can’t.
You wouldn’t wait for your car to start losing power before getting it serviced & even people need a routine check-up now & then. Perhaps when I login next there will be an answer to the question I actually asked.

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Why not go back to the supplier that supplied and installed your system originally?

Following Choice’s guides on solar PV the most important credential is a CEC accreditation. And of course an electrical license for the state you live in.

Apologies if this appears to be self help.

Many local Residential Electrical Contractors are accredited for solar PV work. It’s another good place to look for support, assuming your original installer/supplier is not available.

Without monitoring or data though it appears pointless and possibly a waste of money if your system is performing consistently.

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Perhaps look for those accredited through the CEC as @mark_m suggests. You can find their website at https://www.cleanenergycouncil.org.au

A list of their members can be found at the following page

https://www.cleanenergycouncil.org.au/membership/current-members

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The Clean Energy Regulator also has some advice.

http://www.cleanenergyregulator.gov.au/RET/Pages/Scheme%20participants%20and%20industry/Individuals%20and%20small%20business/Solar-panel-system-maintenance.aspx

Some key points from this are:

  1. The Clean Energy Regulator does not regulate, or have expertise in, the maintenance of solar panel systems. However, below we have set out some general tips you may wish to consider when you are seeking to engage someone to provide maintenance services.

  2. Like all electrical equipment, regular maintenance of your solar panel system is necessary. Please take note of and follow the maintenance schedule provided by your solar retailer or installer.

  3. It is recommended that solar panel systems should only be inspected and maintained by a licenced electrician or Clean Energy Council-accredited solar panel system installer.

It’s my emphasis in bold above. The expert on your system is the original retailer/installer.

If there are concerns or issues with your existing system going back to the original solar retailer or installer is common advice. It is also important if there is a warrantable issue with your system to seek remedy initially from the retailer/installer.

If the retailer or installer is no longer in business the warranty reverts to the importer/manufacturer. The Hyper-linked CEC list of accredited solar PV system installers is one resource that can be used to locate an alternate service provider in your locality. To be accredited the installers are also required to demonstrate system design expertise. IE technical/design knowledge necessary for system component selection and design performance.

If you need to consider replacing your 8 year old inverter, SolarQuotes has a useful guide on major suppliers.

The CEC also maintains a listed of approved inverters.

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Solar panels do degrade over time, averaging about 1% p.a. from their ‘as new’ condition.

Some utilities implicitly encourage servicing to test the anti-islanding aspects of the inverter. They do this by ‘reminding’ that we could be held liable if it fails and we have not had it checked and a lineman gets a shock from our output during a repair event.

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Yes you are correct about degradation over time which was covered by an earlier post…but changing a inverter won’t impact on the output of the solar panels being connected to the inverter. If the panels have an output 90% of new on the old inverter, they will have 90% output on a new/upgraded inverter. The inverter won’t influence what the panels generate.

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I had not addressed anything but that panels do degrade.

Another aspect is that as the solarquotes blog reinforces in the body and comments, the price one may pay for a few extra years of slightly better output is hard to quantify as being economically important or even relevant to buying ‘the best’ versus ‘just good’.

The blog is excellent and speaks for itself.

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I read and record our electricity meter import and export numbers at 10:00AM and 6:00 PM daily.

I also read and record both our inverter readings and our neighbours’ readings, who have an identical system, at 6:00 PM on the last day of each month, commencing in March last year for ours and May last year for theirs.

Should anything go astray with either system, it will be immediately obvious, especially with comparing a particular month to the same month in the previous year.

Or if the variation is due to weather conditions in a particular month, it will also be obvious as both systems should be affected the same.

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It can.

The the high power inverters installed with rooftop PV systems have a technical feature described as MPPT.

Different panels and array configurations have slightly different optimum performance points. There can be mismatched inverters, usually due to incorrect setup or a system selection/design failure by the supplier. I’m not suggesting this is the norm. The likely difference in performance if there has been an oversight a few percent.

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What comes out of the panels will remain the same immediately before and after a inverter replacement as it is likely that the existing inverter has MPPT capabilities since the technology has been around since the 1980s.

As indicated in an earlier post, different inverters have different efficiencies (transformer v transformerless inverters for example as a 8 year old inverter is likey to be the former) and may result in a small increase in inverter output. Over time, changing an inverter to seek these minor gains won’t pay for themselves or be financially viable proposition.

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Interesting? It’s a technical discussion.

As a simplification, yes replacing one MPPT inverter with an other should make no appreciable difference. It’s not absolute. As you note transformerless inverters, are marginally more efficient when compared with older Transformer based designs.

For those into caravanning etc, or older low power off grid, PWM design inverters were common, 60-70% efficient. They were lower cost, and fine for smaller systems designed to operate primarily as battery chargers. There are now more affordable lower powered MPPT inverter chargers as replacement. There is a significant improvement for those users who upgrade.

At a more techie level.
There are different strategies (algorithms) used by inverters to find the optimum operating point. There are differences in how they perform. Additionally inverters are designed to be most efficient with a particular array configuration. This varies between manufacturers and products.

The simplification is well made quality MPPT PV residential supply designed inverters should provide similar performance. There are technical points that explain why there will be small differences.

I’d be concerned that if PV Inverter output was significantly less than expected, the real issue is more likely with the panels (shading, dirty, damaged) or their interconnecting cables.

None of this solves a problem. Our discussion in general does however suggest, why the door may be open for the majority of home PV owners to be taken advantage of by less than reputable local electrical contractors or solar PV business operators.

Not all home owners are keen to learn or take up a more in depth interest in their rooftop solar. As a consequence those home owners need to have a local supplier/installer than can rely on and trust to do only the work required at a fair cost. Once bitten twice shy for too many.

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I agree and a major concern…especially for the layperson as a salesperson could bamboozle them with ‘technical’ information (viz. sales pitch in disguise), making an upgrade sound worthwhile, when it has no significant benefit for the consumer. If one doesn’t have any problems with their current PV system and if one searching for answers to a perceived problem, this is a gift to a salesperson.

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The big difference, I organised by waking down the panels by myself, just with clean water and a caraway-brush.

Assume you mean ‘washing’.

Ours get a build up of wattle and pine flower pollens. Fortunately we’ve had some decent rain often enough to do the job. The panels are also set at 45degrees pitch, which helps.

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