Solar panels, inverters and batteries

Solar panels

2019 is the year when we will see the last of the standard polycrystalline (poly) panels as the more efficient half-cut (also known as half-cell) polys and monos arrive from almost every major manufacturer. Half-cut panels take those same poly or mono cells and cut them in half so instead of 60 cells you have 120 half cells. This means less resistance and a significant bump in performance in the heat and shade. It also makes them more space efficient so, for example, you only need 21 x 315W half-cut panels to achieve 6.6kW compared to 24 x 275W poly panels.


However, if you want rock-bottom pricing then now is the time to snap up the last of the 'polys' with many of the Tier 1 brands unloading at never-seen before pricing. So now, all the 275W polys from Jinko, Trina, Eging, Seraphim, and our own favourite having done us proud for years and years without a single fault, ET Solar, are all free with their cost less than or equal to, the Government incentives (STCs).

REC, a Norwegian company who make their panels in Singapore and are now so confident of their product that they offer a 25 year defect warranty, were the early pioneers of half-cell panels and have had their TwinPeak poly brand out for years, but now nearly all the major brands are offering half cells. REC have moved into half-cell monos, as have Q.Cells with their superb Q.Peak Duo model. Q.Cells are German engineered, made in South Korea and have won some outstanding awards including 'Best panel' in 2018 Intersolar. Risen have a slightly less space efficient half cell mono panel (315W) than REC and Q.Cells, but it has a quite remarkable temperature coefficient of -0.29% per degree C which is on par with SunPower X, the most expensive panel available in Australia. The other thing that has us scratching our head about Risen is the price. 6.6kW of them costs only a couple of hundred bucks more than the 275W polys being sold off on the run-out specials. It's not like Risen are an unknown, they are the 7th largest in the entire World for panel shipments with over 15 million panels in 2018.

LG (made in South Korea) are sticking with their tried and trusted Neon2 panels and like REC and SunPower, are now giving a 25 year warranty. These 330W panels will cost you $3,000 more for a 6.6kW installation compared to the polys, which for those who are buying panels with an expectation to use them for 25 years or more, means just an extra two years of solar production to pay them off.

Our opinion on which panels are best

If you are likely to be in your house for ten years or less we honestly think it makes no difference what panels you buy as long as they are made by one of the World's top 30 brands (Tier 1). You can get the cheapest, or pay a little more for a half-cell and get a bit more output, or pay a little more and get an all-black panel that look great on a dark roof, but in terms of reliability they are all good, and warranteed for, at least ten years.

As soon as you start planning for longer than 10 years then quite a lot of new things come into play. Better outputs over the longer term from more expensive panels with better quality cells that degrade slower, coupled with longer warranties, start to justify the higher initial outlay.

Blowing our own trumpet for a moment, we started offering a free system performance report service, every three months, to our customers in 2011, and we continue to offer it today. It gave us a huge database of statistics, useful feedback to our clients, whilst providing an early warning to deteriorating panels. Q.Cells are the best performing brand of panels over time with LG and REC averaging 0.5% behind. ET are the best performer of the cheaper brands both in terms of long term reliability and output, followed closely by Canadian Solar, Longi, Suntech, Jinko and Trina and GY bringing up the rear, a full 10% behind Q.Cells.

There are many brands on our customers rooftops that don't exist anymore having been absorbed or defeated by the Tier 1 giants. Overall, we have had a failure rate of one solar panel per year per 8,000 installed. We read reports in the media, as no doubt do you, of solar panels failing left, right and centre, or outputs being over-stated by manufacturers, but we've got the data for our own installs going back over eight years now, and we're just not seeing it. Perhaps we are lucky.

Solar Inverters

If you've read what we wrote about solar panels you'll find that much the same advice applies to solar inverters.

Namely, if you are moving house in ten years or less, it doesn't really matter what inverter you buy. The current models, cheap or expensive are all perfectly reliable enough, and almost all warranteed to last for at least five years with 10 year warranties either being standard or just an extra $100. They all have strong WIFI and not too much 'Chinglish' in their web/smartphone reporting.

Of the cheaper brands, all around $1,000 for a 5kW single phase non hybrid model, Goodwe, Sungrow and Growatt have been very reliable performers and JFY, ABB and Delta the worst. Delta and ABB have new models that by all reports from other solar companies installing them, are good now, but it's a case of once bitten twice shy for us.

For about $1,000 more you get a premium Fronius, SMA, or one of the single phase hybrids (plug and play battery ready) from Huawei, Goodwe, Sungrow and SolarEdge. We expect to see a single phase hybrid from Fronius some time this year and with SMA dumping Zeversolar and the rest of their Chinese operations, and moving back to German production, we hope to see good things from them as well.

If you have three phase power to your home then it's usually (but not always) best to install a three phase inverter. The recommended brands are the same as with the single phase inverters, but you'll be paying between a $100 and $500 more for the three phase components, and if you want a hybrid inverter it's slim pickings right now with Fronius and SolaX (not a brand we recommend highly) only, but Goodwe and Huawei three phase hybrids due any day now.

There are a few other inverter brands to the above available such as Solis, Zeversolar, Enphase, KStar that are no doubt fine but we don't do them, but nothing like the number that existed when we first started where most have been consigned to a council tip somewhere, or fallen under the soldering iron of our in-house electronics genius who replaces their blown cheap relays and breathes life back into those that it is economically viable to resuscitate.

When we design a system the first thing we check is shade. Shade from trees, TV antennas, flues, satelitte dishes, neighbours roofs etc because shade kills solar. It's often better to have one less panel than have that panel get some shade and drag down the others with it. Nearmap is an amazing design tool for checking shade as we can see pictures of your roof at different times of day through the year (or years).

If shade is unavoidable you can fit an optimiser (Tigo) to any shaded panel. This won't help that panel itself, but it will stop the others being dragged down. Some inverters (Huawei and SolarEdge) have their own optimisers. Huawei lets you use them where you need them, but the SolarEdge technology actually relies on you installing an optimiser on every panel, shaded or not. Optimisers cost between $70 and $90 each fitted.

We have an FAQ all about batteries that we urge you to read, but its like this...

If you buy a single phase hybrid, e.g. Huawei, Goodwe, Sungrow, then you simply plug a battery into the inverter whenever you want.

Most inverters are not hybrids and don't have the ability to connect a battery but you CAN connect another inverter to your switchboard, and then connect a battery to that.

The case for hybrids is all about cost, because you aren't doubling up on inverters.

For example, a hybrid Huawei inverter with it's smart meter costs about the same as a non hybrid Fronius..both about $2,000.

With the Huawei you can plug in a LG Chem battery for an unsubsidised price of $9,000 (we don't have battery subsidies in WA yet)

So $2,000 for the inverter plus $9,000 for the battery = $11,000.

Compare that to $2,000 for the Fronius and Tesla Powerwall 2, which includes the extra inverter and smart meter and costs $16,000 installed making $18,000 all up.

In fact, it is usually cheaper to replace the existing inverter with a hybrid + batteries than connect a Tesla Powerwall 2 and a lot faster too as the waiting list for Tesla Powerwalls is longer than the one for their cars apparently.

Of course, with a return of about $1,000 a year from the batteries, neither is an attractive proposition until we see Government subsidies or removal of feed in tariffs, both of which are apparently being considered.

 

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, bifacial...you 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...but hopefully not for much longer as SMA are moving back over the next few years to fully German manufacturing. 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.

Delta

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.

Sungrow
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.

 

Growatt

Long history in Australia (2010) and 200,000 installed here. Well priced, 10 year warranty, WIFI included. Great support. Definitely worth considering.

Zeversolar

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 and they are selling it off and moving out of China. Zeversolar will probably carry on but without SMA's money and technical expertise, it's a worry.

 


 

 

 

 

 

 

 
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