SolPlanet is a new Chinese inverter that has recently entered the Australian Solar market. 8 months ago, SolPlanet contacted me and asked me to test their new solar inverter, and obviously review it. When any manufacturer offers me a product to review, I always say the same thing. I don’t do inverter unboxings. I do crash tests. I’ll test it and review it, but if it’s a rubbish inverter, you’ll get a rubbish review. SolPlanet was up for the challenge.
This review is partly my impression of the Solplanet inverter’s features, specifically the limited flexibility of the inverter and the online monitoring platform. But what I found most surprising was when I crash-tested it. I ran it to its limit, side by side with a Fronius inverter, and saw some noticeable differences.
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Through this review though remember this inverter is cheap. It’s about $1000 less than a Fronius inverter and $200 less than a Sungrow inverter. So if it looks like I’m being harsh with this review, keep it in context. We’re dealing with a cheap inverter. All I’m trying to do is point out how an inverter can cost $1000 more than another. I’ll leave it to you to decide if it’s worth the extra money. Each to their own.
The Company Behind SolPlanet
Before we get to the tech stuff, let’s do a quick look at the company behind SolPlanet. SolPlanet is made by a company called AisWei. AISWEI is an inverter manufacturing company. Until now, they have always just made inverters for other companies. The most well-known brand they manufacture for is SMA.
SMA is known as a quality German inverter manufacturer, but for the last 5 years or so, SMA has outsourced the manufacturing of their smaller residential inverters to AISWEI. I did a review of the Chinese-built SMA inverter back in 2017. It really didn’t impress me all that much. I think it’s a Chinese-quality inverter with a German badge.
AISWEI also made an inverter called ZeverSolar. Zeversolar is a brand owned by SMA, it had fancy marketing material and harnessed the success of its German parents, SMA. But Zeversolar’s attempt to get a slice of the Australian market was a failure. They packed up and bailed out in 2019.
That’s a pretty dodgy story, but to be fair, the fact that Zeversolar bailed is no real reflection on AISWEI. AISWEI just manufactured the inverter.
After a decade of making inverters for other companies, and the same year that Zeversolar pulled up stumps, AISWEI started making inverters for themselves. When deciding what to name their new inverter, It seems they choose to do the opposite of Zeversolar and didn’t spend a penny on marketing. SolPlant. Seriously?
SolPlanet is now selling inverters in 6 countries, they have an office in Melbourne with 4 staff and half of them are Solar tech-heads. So that’s a good start. Can AISWEI make a reliable SolPlanet-branded inverter? Maybe. The limited experience I had with Zeversolar wasn’t very exciting. But the Chinese-made SMA is meant to be fairly reliable from what I’ve heard. But more importantly, If an SMA inverter fails, I’ll bet you SMA will be here in Australia to fix it. SMA has a reputation for honouring their warranty, and they have great after-sales support too.
Will SolPlanet be around to honour inevitable warranties? I have no idea. But SolPlanet doesn’t have much skin in the game here. If they pull off making their mark in the competitive Aussie market, your warranty will be fine. If they don’t get traction in Australia, they’ll probably pull out of Australia like Zeversolar did, and you’ll be screwed.
SolPlanet Inverter Build
Ok, now it’s time to get into the fun stuff. We’ll start with the inverter build.
It looks ok to me. It’s a heavy inverter with a big heat sink. Which looks like it would help with cooling, but we’ll see how that turns out later. It doesn’t have a screen – which is common, but disappointing. Some homeowners have better things to do than making sure their inverter is constantly connected to the internet. A screen is a useful backup and a simple diagnostic tool.
SolPlanet has an In-Built DC Isolator
The Solplanet has an inbuilt DC isolator. That’s great. Some cheaper inverters require an external DC isolator which just creates more expense, more work, and more failure points. In reality, an inverter without a DC isolator can never practically be installed in an area that sees even 8 am sun. Because by Australian standards, the external DC isolator cannot ever be in direct sunlight. So that’s a big tick there.
Let’s turn to the spec sheet. Its input current limitation is 12 amps. That’s actually typical for cheaper Chinese inverters. But it means you can’t install panels on more than two orientations. So if you have a roof with multiple smaller faces where you need to point the panels in more than two different directions or two different tilts, then the SolPlanet is not even an option for you…. yet.
At the end of 2021, SolPlanet will solve this flexibility problem – but no doubt it will come at an additional cost. They are coming out with a new range of single-phase inverters with three inputs, or three MPPT’s. That range of inverters will have even more design flexibility than Fronius. When I heard SolPlanet was SOON TO BE offering inverters with three MPPT’s, I got a bit excited because three MPPT’s can be a really good shade solution. But as I’ll explain soon, Solplanet has an important missing feature that makes it a bad option for shaded roofs.
But getting back to the inflexible 5kw Solplanet inverter currently available. Let’s say your house roofline is big and simple and an inflexible SolPlanet inverter will do the job. Would I recommend SolPlanet then?
Still No. At the time of writing this, the Solplanet monitoring platform does not allow consumption monitoring. If you don’t know what that is, you probably should. A consumption monitor just allows you to see how much electricity your house is consuming – whether it be power from the grid or power from the solar. I think a consumption monitor should be considered essential when you install solar. The fact that you don’t have that option with SolPlanet is disappointing. SolPlanet tells me that option is coming soon. But I haven’t had a chance to review it. If it doesn’t have a quality and affordable consumption monitoring option, I think this inverter is a waste of space.
Apart from consumption monitoring, the monitoring platform is ok. It’s simple enough for end-users, and there is enough data for electricians to remotely diagnose any problems. The data is recorded in 10-minute resolution, which is pretty average but not a deal-breaker.
But maybe you don’t care about consumption monitoring or online monitoring at all. Or maybe by the time you read this they have a quality consumption monitoring option available. Let’s turn on the inverter and see how well it works.
I started off by doing a side-by-side comparison of SolPlanet and Fronius. Every now and then I hear salespeople or even installers say “this inverter or this panel I installed at my place cranks! I got 40kWh yesterday”. Just to point out the bleeding obvious, that’s not a very scientific approach to performance testing.
I have two identical 8kw solar panel arrays on my roof that I compare two inverters at the same time. I switch the inverters around to make sure one array is not performing better than the other. I use third-party monitoring – SolarAnalytics. I also make sure the CT Meters on solar analytics are reading the same.
Yes, 8kW is well oversizing. But it was wintertime, and I faced the panels east and west. So it’s similar to installing a 6.6kW system facing north in summer.
This is the part where you think that I’m going to say Fronius performs much better than SolPlanet. Well, no. First, I tested them under normal conditions on a clear day, they seemed to operate about the same. Then I shaded some of the panels by clamping identical core flute and posts to the edge of the same panels on each system. Both inverters handled this type of extremely lite shade about the same. Now I’m not about to keep these systems running for 12 months to see how they work in summer and how they work in different cloudy days and moving shade. So I crash-tested them.
First, I wanted to see how the inverters worked in extreme conditions. So two of us threw cardboard on two panels at the same time and removed it after a period of time. This is one graph that shows the results. SolPlanet just could not keep up with Fronius. What is Fronius doing better? This is just a result of Fronius’s superior maximum power point tracker. In other words, Fronius just has a better way of making small but rapid adjustments to get the most out of your solar panels.
Does Solplanet have a less responsive maximum power point tracker? No, it’s much worse, Despite what they first told me, Solplanet doesn’t have a GLOBAL maximum power point tracker. But what is global maximum power point tracking you might ask? In short, every ten minutes, a global maximum power point tracker does a thorough check that the inverter is performing as well as it can. It makes infrequent large adjustments to make sure you are getting the most out of your panels. The global maximum power point tracker doesn’t often find a problem, but when it does, it finds a big problem that was worth correcting
Look at the chart. When shaded, SolPlanet continually produced 700 watts less than Fronius. Both systems had identical shade. SolPlanet however, responded poorly to that shade. It got stuck operating at an inefficient spot and only corrected itself once the shade was removed. But if it had a global maximum power point tracker, it would have corrected itself within 10 minutes.
Fronius call their Global maximum power point tracker “dynamic peak manager” SMA calls it “shade fix”.
It’s sometimes hard to pinpoint out the differences between a quality inverter and a cheap inverter, but here is one clear example. Sure, systems don’t normally get cardboard thrown over them. And it’s possible that in reality a superior MPPT algorithm ALONE won’t result in that much of a performance increase over the life of the system. But to me, this just points to a bigger picture. Cheap Chinese inverters just are not built the same way.
Next up, I wanted to see how HOT each inverter runs. There is a rule of thumb in electronics that for every 10 degrees hotter a piece of electronics operates at, the expected lifetime is halved. In other words, heat kills electronics fast. (Look up Arrhenius Equation for more info.)
I installed thermometers in both inverters at a similar location, just next to their power stacks on the top left-hand corner. I ran both inverters with the same arrays used in the last test. I heated the room up to 27 degrees, which is still cool compared to summertime. They flatlined at 5kW for about an hour.
First, let’s look at the Solplanet. The outside case got too hot to touch. I measured it at 55 degrees. The internal temperature got to 57.1 degrees.
Compare that to the Fronius Gen24. The outside case got to a mild 35 degrees. The internal temperature of the inverter was 46.6 degrees.
I then pushed the SolPlanet inverter a bit harder and heated up the room to a warm 30 degrees, the temperature the inverter would easily see on a summer’s day. The Solplanet quickly got to 60 degrees on my thermometer or 63 degrees on SolPlanets monitoring. At that point, the inverter started derating to protect itself from overheating. It reduced its power production down to 4.6kW.
But a bit of power loss on a hot summer’s day isn’t what I’m concerned about. Here’s the problem. In my test, SolPlanet ran more than 10 degrees hotter than Fronius. If we made the absurd assumption that SolPlanet used the same quality components as Fronius, then applying Arrhenius’s equation would suggest that the SolPlanet would last half of the time of a Fronius inverter. But I think we can be confident that the components used in the SolPlanet inverter are not the same quality. Let’s hope SolPlanet is around to honour their 10-year warranty.
Or maybe you’re the type of person who thinks you’ll probably move house within 5 years. If the inverter fails, you’ll throw it in landfill and replace it with another cheap inverter. After all, you’re already $1000 ahead compared to buying a Fronius inverter. Whatever floats your boat.
SolPlanet is new to Australia, we don’t really know if they’ll be here long-term to honour warranties. It’s an inflexible inverter, so not suitable for complicated roofs. At the time of writing this review, it didn’t have a consumption monitor. Its maximum power point tracker isn’t great, and it doesn’t have a global maximum power point tracker. So I wouldn’t use it if your panels are anywhere near the shade. It runs so hot I would expect it to derate on a hot summer’s day. And the extra 10+ degrees is going to shorten its life span. But it is $1000 cheaper than Fronius, the best inverter on the market.
What do you think? Am I being too harsh? Should I stop acting like a solar snob? Or do you agree with me? Pay a bit more for better performance, proven reliability, and more importantly, a proven track record from a manufacturer that will stick around to honour your warranty. Let me know in the comments below.