So you’ve just enjoyed your first solar summer with a basic 6.6kW system, but you’re finding the bills in winter still give you the chills, don’t worry; you’re not alone. It’s not uncommon for new solar installations to undergo expansion after the first winter. Read on as I explain how.
This article looks at buyer’s remorse for new systems that should have been bigger from the outset. If you have an older system, please check previous posts in my ‘How to upgrade’ series:
“I’ve never had a customer complain they installed too much solar”
– Anthony Bennett
For years, I’ve used this as a succinct little catchphrase to encourage people to buy more solar panels. Some say it’ll be carved on my headstone, but recently I’ve had to defend this position. The internet experts are pushing back…
- Well, you would say that wouldn’t you, you’re trying to sell something
- It must be a con by big climate… see I told you there’s a SUN TAX coming now!
- People are just try to justify overspending to themselves, it’s ak!chully a waste of resources.
So I’m going to have to simplify it for both the slow crowd and the clever clogs. Remember that “excess” solar is a feature, not a bug.
For over 15 years, I’ve heard one consistent complaint from solar owners:
“I wish I’d installed more panels.”
This isn’t a sales spiel—it’s a common lament I’ve heard time and time again.
Summer on the left shows a mountain of solar, while winter on the right is disappointing when you realise the scale of the graph
An Example: Geez-I-Should’ve-Bought-More
Can my Fronius 5KW Gen24 3-phase – 6.6KWp system can have additional panels fitted?
My system suffers drastically with seasonal shading from council trees. Summer is fabulous, but with an additional bank of five north facing panels, I’d still get 2-3KW more output in winter. I had read the 133% rule can be skirted with a battery, but just to clarify, even then would I still be limited to just two extra panels? Perhaps I should price a small separate system, purely west facing.
Bin The 133% Limit With A Battery
As we’ve explained before, an archaic Australian rule limits solar installations, but installing a solar battery allows you to claim STC credits on the full rated capacity of an inverter. Some inverters can handle 200% or more.
Fronius are conservative so the 5kW Gen24 will handle 150% overdrive, or 7.5kW. At only 6 or 12 months old, finding two matching panels for your existing array is usually feasible.
However, you’ll still need to get the string configuration correct. Happily, Fronius have excellent current ratings, which allow flexible designs of parallel panels to get voltage down & group orientation correct.
Ring up your installer and get them back so that your warranty is kept intact.
In October, this system doubled in size so blue yield went up & grid consumption fell. Black circles still show winter demand is high though.
Can’t Add A Battery? Get A Whole Second System
If your existing solar is working well, there’s space on the roof and you can get a connection approval, then adding solar via a second inverter and solar panel array is often possible. Consider a hybrid inverter for your second system, so your next upgrade can be a battery.
Got 3 Phase? Get A Second & Third System
Network rules dictate how much of any load you can connect to the grid, and often they involve balancing things equally across phases. If you already have a 5kW single phase inverter, adding a 10kW single phase might not be acceptable, but two more 5kW units will.
Our cover image shows a 3 x 5kW system where the owner added a hybrid inverter and kept one of his GE units for a spare.
Whatever you choose, try to stick to the same brand so that you have one consumption meter, one management system, one app to watch, and, importantly, one warranty.
The Takeaway: Go Big AND Go Home
If you’re considering solar, think big. Starting small might seem safer, but the long-term benefits of a larger system are undeniable and upgrading is always harder & more expensive than going big from the outset.
More panels mean more savings, better future-proofing, and a greater positive impact on the environment. So, when it comes to solar, don’t hold back—you’ll thank yourself later.
About Anthony Bennett
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I wish I had of gone bigger and I’ve got 10.66 kw solar optimised with a 5kw solaredge hybrid inverter and a 10kw solaredge battery.
Cost is the biggest factor why I didn’t.
Can add another battery to the existing system but again at $11800 installed, cost is prohibitive
Or drop another $27k for the same system again on the second phase
I would suggest that in many cases, buyers remorse comes about by unscrupulous sales people and or practices.
For example, when I bought my 15 kw 3 phase system, I specifically stated at the time that within 12-18 months I intended to buy batteries and didn’t want to have to spend lots of money changing inverters or such. (Apart from the battery cost and installation of course)
I was sold 3 x 5kw grid tie inverters, a bit like the picture.
The bonus was that the electricity supplier was going to pay me 14 cent FIT, uncapped. Stupidly I believed them.
For the uninitiated the solar supplier has no control over your FIT.
So when the time came, it was a giant headache. Apparently what I wanted done was nearly impossible. (Batteries charging when the sun shone regardless of the grid being up or down, and power to all 3 phases when the grid was down)
They wanted me to replace all 3 inverters with hybrids. I reminded them of our conversation we had 18 months earlier to no avail.
So I ditched the supplier of the panels and ditched 2 of the 3, 5kw inverters and bought a Fronius Gen 24 3 phase Hybrid inverter and 33kw of BYD batteries from a different company that was genuinely interested in discussing MY needs rather than what they wanted to sell me.
Interestingly though, throughout this unpleasant business, I obtained 10 quotes from 10 different suppliers and they all gave me a slightly different version of the same BS.
For clarity my final solution came in 5k over the most expensive of the 10 quotes.
So, did I have buyers remorse? Yep.
So good people, when people tell you to do your research, you may think jumping on FB is the answer, well it ain’t. Use Google and when you find a company you feel might be ok, ask them for reference sites and ring the references. I did it in the end and made my decision on that basis.
You are going to spend your hard earned cash, do so armed with other peoples real experiences and you probably won’t suffer from buyers remorse.
I would love to put extra panels on my roof, but everyone I ask tries to sell me a complete new system which I don’t want because I replaced my 5KW inverter only two years ago!
I’m wondering how I can go about doing this when I already have 13.2kW of panels and a 10kW Sungrow SG10RS inverter on single phase. Swap the inverter for the SH10RS and also get a battery? System was only installed in December 2023 so would seem to be a huge waste of an inverter. Or maybe roll the dice and ask for DNSP approval for extra inverter capacity? Then might be able to get a hybrid system installed.
There’s gotta be a limit somewhere with “too much is just enough”, but with 65 panels and 27 kW, I haven’t found it. That’s just yielding around 3 kW in horizon-to-horizon grey overcast. And global heating seems to be increasing the incidence of that. Fortunately that ~10% yield is enough, though, to top up the battery from overnight off-grid drain, and supply a careful day’s loads. I.e. the large array obviates the need for a huge battery, making for a cheaper overall system.
Then, after a day or two of cloud soup, I can whack 38 kWh into the EV & HWS in a morning, and I’m well ahead again.
If there had been room for more panels on the roof, they’d have gone up. Wouldn’t need much battery capacity then. (OK, lotsa panels means more/larger inverters or MPPTs, but redundancy is a quality of its own when off-grid.)
A second EV soon justifies all the panels you can fit, I figure. There are such households already. Let’s look again in 2030.
I think rainy day/ winter’s day performance will soon be the new criterion for system performance.
When feed-in tariffs were 66c/kWh, panels were put at latitude angle, but these days, running out of roof space, we are starting to realise that flat roofs with horizontal panels maximise whole of sky radiation with 100% cloud cover and north facing vertical walls and fences offer close to optimum mid-winter power at Sydney latitude and south.
Now that’s an idea, Bill – fill not just the roof, but the north wall too.
I did build a 25m long north facing 40-degree tilted roof into the extension. Here at nearly 40 degrees south, that gives:
Equinox: cos(37.93 – 40) = 99.9% optimal
Winter solstice: cos(37.93 – 40 + 23.44) = 93% optimal
The north wall’s 90 degree tilt would then be:
Equinox: cos(37.93 – 90) = 61% optimal
Winter solstice: cos(37.93 – 90 + 23.44) = 88% optimal
As it’s in June – July that total array yield hits a nadir, finding extra roof on the walls, at 88% efficiency, is not shabby at all. (And a significant revelation.) Add that I’d only have to go through the wall to wire to the MPPTs or inverters, and greater convenience would be hard to find. The incidental sun shielding wouldn’t add a lot, as the wall is insulated. (But I did note today that inside the garage, a closed north facing light coloured roller door radiated enough IR heat to be felt on the skin at several meters.)
My experience is that rain massacres PV yield, whether because it’s thicker/denser clouds which precipitate, or due to the changed cloud composition. When it rains, I figure it’s time to minimise consumption, to conserve battery SoC, in case it lasts for days. (Cruising through winter without starting the generator would confirm the adequacy of my system design.)
Some retired folk take up gardening, but a solar installation is more fun than a train set, I figure. (Though I did bring home a 50m roll of netting yesterday, to keep the kangaroos off my cabbages. That should work better than having to open the bedroom window in the middle of the night to berate them. They don’t necessarily move unless you shine a bright light at them. (The kangaroos, not the cabbages.))
Am in Melbourne, and have got 6.4kW of panels installed (3 east, 1 north, and 14 west). Given smallish house, shading and roof suitability this is all I could fit but in an ideal world I’d love to bump up the number of north facing ones.
Using the Enphase panel level monitoring I can see that the single north facing panel has generated 18kWh in June versus an average of 12kWh for my west facing panels and 10kWh for the east facing ones.
West is great for summer, but north is best for winter & heating..
Looking at bigger Solar and battery’s for my house every scenario calculator I look at, and presumably real world as well, has battery’s being charged as soon as the solar systems start producing power in the morning with the assumption that the Battery is empty from the night before.
Most Battery’s under charge seem to consume everything produced by the Solar and as a result export to the grid only seems to happen when the Battery has had as much as it can take.
Such an approach when looked at through the micro lens makes sense, get the free power while its available and if happens that you get all that you need then provide export to the grid.
When you look at that scenario through the big picture lens then as Battery’s become widespread then solar grid export which is good when its controllable, will dissapear in much of the grid until lunch time and then it’ll be back as it always was as a problem because its too much…
Surely with the connectivity and intelligence available to us today we could get a better distributed charging scenario so that solar export will continue to be available while ever the sun is up, and charging should be staggered across all battery owners so that instead of the Battery becoming another source of Grid control issues we use charge of it as a means of stabilising the grid?
Thoughts?