Solar panels, inverters and batteries

Solar Panels

In WA, if you have single phase power then you are not allowed to install a solar inverter greater than 5kW, and you can not oversize that inverter by more than 33.333% so that means 6.66kW is the maximum amount of panel power you can install. If you have three phase power then you can go much bigger, up to 30kW of inverter and 40kW of panels, but again, if you want to be eligible for payments from Synergy for your surplus solar, you have to also limit your installation to a 5kW inverter and 6.66kW of solar panels.


For the majority of people we are quoting these days, getting as close to 6.66kW of panel power is the goal.


The best panel size is 350W. 19 of those gets you to 6.65kW.

Rare as hen's teeth to find 350Ws though. REC have/had one.


The next best size is 315W. 21 of those gets you to 6.615kW
Jinko, Risen and Longi have excellent and well priced 315W Mono panels


After that you have a large number of panels sizes that get you to 6.6kW

24 x 275W polys from ET, GCL and Seraphim are very popular
22 x 300W from Longi, Seraphim, Canadian, and ET are all monos

20 x 330W usually from LG, although Canadian now have a 330W half-cell poly that's only 5cm wider, and longer than a standard panel.


After these you have a variety of different sizes, none of which divide quite as neatly as those above into the magic 6.6kW. 285W panels get you to 6.555kW. Canadian Solar have some of those. 305W gets you to a rather disappointing maximum of 6.405kW, and 295W isn't fantastic at 6.49kW


Does it really matter if you get 6.405kW instead of 6.65kW?

It's 3.7% less. 430 fewer kWhs of power a year. This is an extreme example of course, the worst size of panel against the best, but, heh, every little helps doesn't it?


We could go on until the cows come home about build quality, cell quality, glass thickness, and many people do, but the reality is that pretty much everything available from the top 30 or manufacturers (Tier 1 brands) is perfectly good quality to sit on your roof year after year, decade after decade making electricity. There is no doubt that there is some rubbish around but rubbish panels are only sold by rubbish solar companies and they are pretty easy to identify with just the slightest bit of research. The very highest quality panels we've installed are made by Q.Cells, REC, LG, and SunPower. By that we mean you can see that they are better built, sturdier, but that really doesn't mean much unless you live in cyclone risk areas.


Most panels give a 10 year defect warranty, some 12 years and a handful 25 years. Singaporean made REC who are priced low to mid-range give 20 years defect warranty and an extra 5 years if the installer has done the REC course (we have). Not to be confused with the ambiguous 25 year 'Cell Performance" or "Power  warranty" that all panels provide. REC say that for every million panels they make they provide 60 warranty replacements. Kudos to REC for turning a negative (warranty replacements) into a positive attribute.  REC are by no means alone in making great quality panels at a fair price, but they are currently the only low to mid range priced manufacturer prepared to put their money where their mouth is.


Good looks
If your panels are visible from the street then an ugly install can not only depress you every time you arrive home, but it can reduce the appeal of your home when it comes time to sell.The ugliest installs are where the street visible roof area is split into small sections, so the panels are dotted here and there. The best looking panels are 'all black'. They have mono black cells inside a black frame and a black backsheet. Its the black backsheet that really makes all the difference to the look. A normal backsheet is white and is visible between each and every cell inside the panel. Longi and Seraphim have all black 300W monos at the moment and LG Neon 2 is always available in either white or black backsheet.


Click here for a run down on prices.



Hybrid inverters have battery inputs, everything else doesn’t, which means you can only connect batteries to your solar installation if you buy a hybrid. If you buy a non hybrid then when its time for batteries you have two choices. (1) Throw out your existing inverter and buy a hybrid, or (2) connect another inverter that can run batteries.


It makes us pretty mad to see ads on Facebook and in the newspapers where shonky solar companies are advertising a 'battery ready' system, but using a non hybrid inverter. It costs $500 more to buy a hybrid over a cheap non hybrid inverter but it will save you at least $2,000 down the track.

We discuss this in far more detail here


If you have single phase power, then the largest inverter you can install is 5kW but you can go much larger if you have 3 phase supply to your home. 3 phase inverters are more expensive than their single phase counter-parts.


The cheapest inverters are from Growatt, with Zeversolar, Goodwe, Sungrow, and Delta not far behind. Even the cheapest 5kW inverters cost over $1,000 for single phase and $1,500 for 3 phase.

If you want European made and top quality then Fronius is the brand of choice, Austrian made, and $2000 for single phase and $2200 for three phase. However, not a single one of these above are hybrids.


Single phase hybrids from Huawei, Goodwe, Sungrow, Delta, SolaX cost between $1,600 and $2,200.

Three phase hybrids are available from SolaX and Fronius and cost $3,000 and $3,600 respectively, however Huawei have announced their three phase hybrids will be here by July 2019 and Goodwe even sooner and both will sell for under $2,500.


All inverters come with at least a 5 year parts and labour warranty. 10 years for parts but still 5 years on labour is becoming more common either free, or for $100 extra. Panels are almost indestructible and very rarely fail, but inverters have a lot inside that could go wrong so making sure you have a genuine manufacturer’s long warranty is an intelligent move.

WIFI reporting of your solar output to smartphone apps or web browsers is almost universal now and it’s usually very good. Some brands (Fronius, Huawei, SolarEdge, Enphase) also have optional energy meters often called smart meters that can be installed in your switchboard if you have the space for them, to report on your home power consumption and imports and exports through your meter. They are also needed by hybrid inverters to manage the storage or release of battery power, and to limit exports back out to the grid.



If you have shade on all of your panels during the peak of the day then don’t waste your money on solar, but if the shade is only on a few panels then fitting optimisers at the time your system is installed will cost you about $90 a panel and will stop the shaded panels from dragging down the output of all the others. Tigo optimisers can be installed with ANY inverter, Huawei and SolarEdge have their own optimisers, and Enphase have micro inverters but do the same job as optimisers for shade.  Tigo and Huawei optimisers can be selectively deployed only on the shaded panels, SolarEdge and Enphase require them on every single panel which can get quite expensive.


A typical 5kW inverter and 6.6kW of panels on single phase, single storey house costs about $2,000 to $2,300 with an extra $100 to cover the extra component costs for three phase.
Double storey homes take a fair bit longer, and usually cost $300-$500 more.
Smart meter installs are pretty easy and usually $50 covers it.


Most people have heard of Tesla Powerwall. Version 1 came and went very quickly, Version 2 has a built-in inverter inside the big white battery box and connects to the switchboard. Costs about $11,000 if you are prepared to put yourself on the waiting list for the limited supply coming here.
This is the battery of choice for most people who have a non hybrid inverter but there are other solutions from Goodwe and SMA (and others) that allow you to buy the second inverter, and then use a variety of other batteries.


If you have a hybrid inverter then you don’t need the second inverter, and therefore your costs are much lower. Most of the batteries work out to be $800 per kW, so 10kW is $8,000. LG Chem are the most popular, but BYD, Pylontech, Samsung and Panasonic and others are out there too.


Click the blue brand name for a full review, datasheets etc


Panel manufacturers


Canadian Solar have the largest available range of panels with a variety of straight poly panels, straight mono panels, half cell polys, half cell monos, name it, and all supplied and supported by the local Canadian Solar Australia team.

Trina, Jinko, along with Canadian are 'the big three' Chinese brands with annual sales over $3 billion each, they top the Tier 1 list.

Talesun, ET and GCL and Seraphim are slightly further down the Tier 1 list but still giants in the industry. Smaller available range in Australia than from 'the big three', but what we do get from them has proven to be very good quality, and usually priced a little lower too.

Longi are, and have been for many years, the World No.1 monocrystalline cell manufacturer and we like their panels. Not too many others sell them, but they should. They have a well-priced really looking nice fully black panel, 300W mono. Black cells, black frame, black backing sheet.

Q.Cells. The half-cell Q.Peak Duo mono panel won this year's 'Best panel' award at Intersolar in Munich (biggest solar expo) and the year before they won with their innovative steel frame (everything else is aluminium), so it's clear the R&D and engineering in Germany for Q.Cells is as strong as ever. Well supported by their Australian office, this brand is always more expensive than the Chinese, but it's top quality.

REC panels are made in Singapore and are a good quality brand. They were early adopters of half cell technology with their Twin Peak polycrystalline range and we are now seeing REC half cell monos coming out as well. 25 year defect warranty just introduced. Awesome.


LG and Sunpower. Small range of top quality mono panels at significantly higher prices than average, but with 25 year warranties.



A brief description of each of these top inverter brands

Click the blue brand name for a full review, datasheets etc

Huawei FusionHome inverters are indeed a fusion of everything that is good about rivals Fronius and SolarEdge, all combined into one small and light product. Huawei are already World No.1 inverter manufacturer by revenue (20% of World market) and the new residential single phase and three phase hybrids are only going to increase their lead.

Battery interface built-in, DC optimisers for eliminating shade issues with panel level reporting, excellent WIFI and a 10 year warranty make this product very hard to go past. Huawei are 83rd on the World Fortune 500 list with sales of US$75 billion last year.

Fronius make excellent 'string inverters'. Primo range for single phase, and Symo range for three phase. All 100% European made (Austria), 10 year parts and 5 year labour warranty. Excellent reporting via inbuilt WIFI. A Hybrid version of Primo is expected before the end of 2019. Fronius have 4% of the Worldwide inverter revenue.

SolarEdge. Every solar panel has a SolarEdge power optimiser attached and in so doing, at great expense, allows every panel to operate as a law unto itself. Shading, roof orientations mean nothing to the flexibility of SolarEdge. However, a very confusing array of products, best explained by clicking on the blue SolarEdge link means that many end up with (not from us, of course) something other than what they thought they were buying. SolarEdge have 8% of the worldwide inverter revenue, and are particularly successful in the USA.

Goodwe are perhaps the surprise near the top of this list of heavyweights but it ranks highly because it is so reliable, has very detailed reporting via WIFI and the company built their name in the challenging battery inverter market. They have the most comprehensive range of Hybrid inverters, and retro fit DC and AC coupled solutions that can be used to put batteries on ANY solar installation, new or old, single or three phase.

SMA German company that still makes their smallest inverters in Germany (1.5kW and 2.5kW) but the rest are made in China. We hear the move to China saves $80 an inverter compared to making it in Germany, but in Australia, the brand name, so popular for such a long time for being German not Chinese made, was seriously damaged by the move. Nice AC Coupled battery inverter (SMA Sunny Boy Storage) that can be added to any solar install new or existing. No matter where the inverters are made, this is a top quality product range to put on the shopping list alongside Fronius, Huawei,and SolarEdge. SMA are second behind Huawei with 13% of the worldwide inverter revenue.

Enphase make an excellent micro inverter, similar in function and price to SolarEdge except there is no central inverter. The conversion from DC to AC happens on the roof with each micro attached to each solar panel. Good reporting via WIFI through a small control unit (called Envoy). We stopped doing Enphase three years ago for reasons we won't put here.


Good inverters priced a few hundred more than most other Chinese brands because they provide a full 10 year parts AND labour warranty. Now they have WIFI (finally), they are a good choice.

Solid range of single and three phase inverters plus a nice single phase hybrid that works with any low voltage (48V) lithium or lead acid battery. Good to see the new Sungrows have re-introduced the LCD screen on the inverter. WIFI works very well and their 18 strong office in Sydney (since 2012) provides excellent support (Telephone 1800 786 746). Sungrow have 10% of the Australian inverter market and 11% globally so certainly a very strong brand.



The cheapest inverter in all categories by a couple of hundred dollars and a fair choice if on a tight budget.


German SMA bought a large share of this company as a way to get into the Chinese market, but apparently things have not gone well financially for SMA with this deal. . They are often advertised as 'German' which they aren't, and the quality of a Zeversolar isn't the same as an SMA, but they seem to be on par with any other regular inverter for quality.