Solar Panels and Inverters

May 13th 2017

Which solar panels perform best in Perth? We have been running a rooftop test for over three years now on a Bassendean house, and the latest results are listed below.

                                                                                

Brand
Description
Tier 1
Rank

            % Gain

12/2/2014 though to 13/05/ 2017

Q.Cells
German engineering - The Best
Yes
1st
+13.72%
Canadian
Great panel, huge company
Yes
2nd
+12.61%
ET
20% better warranty too
Yes
3rd
+12.52%
         
2nd on the Tier 1 list
Yes
4th
+11.03%
Renesola
Huge Chinese firm
Yes
5th
+11.01%
No longer available to sell
Yes
6th
+10.63%
REC
Singaporean made
Yes
7th
+10.44%
New on roof Dec 2016
Yes
8th
+ 9.87%
Trina
New on roof Dec 2016
Yes
9th
+8.10%
Jinko
Surprisingly poor results
Yes
10th
+6.06%
GY Group
Tier 2 panel - Benchmark
No
11th
0.00%

 

So, is one panel much better than any other?

Much better ?...no. If you owned a massive solar farm then a few percentage points difference is going to make a huge difference, but for typical 5kW or 6kW residential solar installation, even a 10% swing means no more than $200 a year of power savings.

Our policy is pretty straightforward. The higher up the list on our test roof, the more we get behind the panel, so we typically sell the top 4 or 5 panels. As a result, we get a very good buy price, and therefore so do you. That's how it works folks. The more a solar company sells of a brand, the cheaper they are, so most solar companies play a favourite.

Many of the largest companies sub-contract out a substantial percentage of their exports to smaller Chinese factories. Whilst quality control is meant to ensure the products are as good as the original factory, our experience with some brands has been very hit and miss. Case in point, our Jinko panel on the test roof (above) is performing pretty horribly, yet Jinko are the No.1, by volume, manufacturer in the World. Mind you, considering what happened to the previous No.1s, Yingli and Suntech (bankruptcy issues), perhaps shooting for No.1 isn't all its cracked up to be.
ET Solar have given us a written guarantee that 100% of the panels we install of theirs are made in their own factory and Q.Cells don't sub-contract either.

A quick word about these top 4 panels (click the blue name to go to their website)


Q.Cells. All Q.Cells research and development and engineering is done in Germany, and the Monocrystalline PLUS range are still made in Germany, but the slightly cheaper PRO (Polycrystalline) panels are made in Korea, Malaysia and China. Now owned by Korean conglomerate Hanwha, the future for Q.Cells looks very bright. After decades of production, they remain the best solar panels in the World. You may not see why from a spec sheet, but when you see them up close, its obvious how well made they are. You don't get double the standard wind loading capability with a regular frame. Brochure

ET Solar. ET were an early arrival in Australia (2008) compared to most, and we, and many other Australian solar companies, have been fans for many years. Established in 2005, they became Tier 1 listed by Bloomberg in 2012 and now have 3,000 employees, and annual sales over AUD$1 billion. We've installed many many thousands of ET panels over the years, and never had a single faulty panel. 100% of ET panels we install are guaranteed to be manufactured in their own factory. That's unique and ensures the highest quality control as almost everyone else sub-contracts out their manufacturing to smaller firms to keep up with demand. However...their Monocrystalline panel (ETM2660250WW) was not especially good in the Australian heat (Temp Coefficient -0.44%) and was discontinued a few years later. The ET Solar range is now entirely Polycrystalline and a top performer in low light and the heat and comes with a 20% better defect warranty (12 years) than most. Top quality, proven performer. Brochure

Canadian Solar. It's a fantastically well engineered panel (all of their product ranges are great) but it's never been to Canada. Everything that arrives in Australia comes from China.

For the past three years, ET and Canadian have been fighting it out for second spot behind Q.Cells on our test roof. In real terms, nothing to pick between them for performance, but normally we get a better buy price on ET and the warranty is better, so that's what we sell most of.
Brochure

GCL. Established in 1990, GCL have been around longer than anyone in the solar cell manufacturing business and their in-house panel manufacturing capacity puts them second out of the thirty brands on the Bloomberg Tier 1 list just behind Jinko. Since they bought into Australia's largest solar trade wholesaler (OneStop Warehouse) GCL have really made their presence known. The results on both our test roof (above) and customer rooftops has been first class. Brochure

Do you want to understand what all that stuff on the brochure actually means?

We have extracted the key pieces of data from the Q.Cells, ET Solar, Canadian Solar, Jinko, GCL and Sunpower brochures and put the numbers alongside each other. Then we describe what it actually means to you. Click here

What is a Tier 1 solar panel manufacturer?
Tier 1 solar panel companies are measured the same way as Blue Chip companies listed on the stock market. Well-known brands, profitable, able to withstand the ups and downs of the World economy. Bloomberg New Energy Finance provide a list of the solar manufacturers of Tier 1 panels. If a company is financially struggling, Bloomberg remove it from the list. It's a measure of financial strength more than being about the quality of products, although of course, the two are obviously closely linked. Click here for the most up to date Bloomberg Tier 1 panel list.

 

SMA. Forget everything you ever knew about German SMA, because the new range of Sunny Boys are MADE IN CHINA. They have also removed the awesome LCD screen, so now the only way to see your data is via WIFI/Smartphone which rules out large swathes of the 'elderly market'. Coupled with some fairly dreadful service/repairs it would seem that SMA are throwing in the towel and handing their business to Fronius (below).
See table at the bottom of our Prices page for current SMA inverter prices.

Click this link for SMA inverter review

Fronius, made in Austria. The best 3 phase residential inverter, even better than SMA. Their single phase Primo range is also top quality. The Australian version of the 5kW Primo is rated at 4.6kW, allowing a maximum of 23 x 265W (6.095kW) of panels. We also stock the International version of Primo 5kW which can have an extra 2 x 265W panels connected.
Warranty on both is the same (currently 10 years parts, 5 years labour). WIFI included free with data viewable on a web browser or smartphone app.
See table at the bottom of our Prices page for current Fronius inverter prices.

Bosch (German). Nah, not really, despite Bosch having a very strong brand name. Only a little cheaper than SMA or Fronius and not worth the discount. ABB (Italian) is pretty good but again, not a big enough price difference to not buy SMA or Fronius.

Goodwe, Now the only Chinese made inverters we will put our name and reputation on the warranty for. Made their reputation in the off-grid market, huge solar farms, battery systems, and appeared to have fallen into residential solar inverters simply because it was so much easier than the off-grid area they were masters of. The good news for us, for you, is that the components and build are first class. They cost hundreds of dollars more than the cheap Chinese inverters that pretty much no-one will touch any more.

Click here for a full review on Goodwe inverters
See table at the bottom of our Prices page for current Goodwe inverter prices.

Sungrow. Good, but not great inverter despite being World No.1 by volume and having a pretty good rap sheet from the review mags (Photon). Priced almost identically to Goodwe, we prefer the better component and build quality in Goodwe. Like the new Chinese made SMA SunnyBoys (single phase) the LCD screen has been removed and the level of WIFI information isn't as detailed on what you get with Goodwe or Fronius.

Enphase Micro Inverters
An inverter sits underneath every panel, allowing them to operate independently. Great for situations where trees, buildings etc shades some of the panels, some of the time. Also, great if you want panels facing in multiple directions. The latest Enphase micro works on single or three phase homes and has excellent reporting information from the Envoy WiFi unit. Expect to pay $2,000 to $3,000 more for this solution than a good string inverter. Even if there is zero shade, you'll get an average of 6% more power over a year from Enphase over a string inverter, simply because of the way they handle shade from clouds...that's like having one extra panel.

SolarEdge make a quite remarkable product. A DC optimiser plugs into the back of every panel and then runs back to a central single or three phase inverter. This solution allows panels to be placed on any roof orientation and gets around the issue of partial shading that string inverters (above) can suffer from. Excellent WIFI reporting too right down to individual panel level. The only bad thing is the price. See our prices page

Click here for a full review on SolarEdge inverters

And then there's what's left over....

Most of the total rubbish that swept Australia in the boom of 2011-2013 has gone, de-listed by the Australian Government's Clean Energy Regulator at the end of 2016. What's left is a list of Chinese inverters that are most certainly better than they were due to learning the hard way from awful decisions on cheap components (can't tell you how many relay failures we've seen). The likes of Growatt, Delta, JFY, Zeversolar are still there, selling entirely on price or extended warranty. Your choice. Just consider that a 10 year warranty on an inverter that fails every couple of years and takes a month to get a replacement each time is perhaps not worth the $400 initial saving.

 

Inverter Technology
Whilst panels are so simple with no moving parts and almost never fail, inverters by contrast are expensive and work hard all day long and are packed with electronic components and software.

There are four different types of inverter technology.

1. String Inverters
2. Hybrid string inverters for battery storage
3. Micro Inverters
4. DC optimers and associated inverters

1. String Inverters

The most common type of inverter is a string inverter with the panels daisy chained together in series. Typically the inverters these days have the ability to have a string of up to 14 panels on one roof orientation, say North, and a totally independent array on another orientation, say West. Most will also require a minimum of 4-6 panels on each orientation (MPPT is the correct term) to provide enough voltage to start up.

The weak spot with string inverters is that if one panel in the string is shaded then all the panels in that string will be pulled down to match the reduced voltage of the shaded panel. See section 3 about micro inverters.

2. Hybrid Inverters
With solar battery storage the hot subject of the moment, Hybrid inverters from the likes of Goodwe and Fronius are seeing a lot of interest. A Hybrid inverter looks and behaves just like a string inverter, but contains extra software and components that allow it to charge batteries and release power when needed from the batteries. Typically hybrids cost at least $1500 more than a regular string inverter. We have put together a 5 minute Youtube video on battery storage, hybrid inverters, the economics of it etc at the link below, or Google 'Youtube Solar Battery Storage Perth'.
https://www.youtube.com/watch?v=is8O68khviA&feature=youtu.be

.

3. Micro Inverters connected to every solar panel

It costs about $100 extra per panel to have a micro inverter compared to most string inverters. The advantages of micros are fourfold compared to string inverters.
Each panel is a law unto itself so shading of one panel doesn't have any negative effect on an unshaded panel
.

You can point the panels any which way you like too, North, West, East, it makes no difference.
The DC to AC conversion is done on the roof so the maximum voltage running through the solar conduit is 240V, not potentially 600V with a string inverter.
You don't need to find space for a large box to put on the wall.

Enphase are the best micro inverter brand for handling Perth heat.

4 .DC Optimsers and associated inverter

Similar extra cost as micros, you get a 'micro' on each panel but you also get a central inverter that does the DC to AC conversion. Same advantages as micros for shade and roof orientations.

It's actually the safest (1 volt per panel open circuit), and most efficient solution with excellent WiFi  and smartphone reporting and a 25 year warranty. SolarEdge have this section of the market won hook line and sinker. Want the best of the best? This is it.

Download SolarEdge product overview
Download SolarEdge reporting software overview

 

 
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