It’s been 18 months since I first wrote this SolarEdge inverter review. Since then SolarEdge lawyers have sent me threats about this blog, we installed 130 SolarEdge optimiser systems and I have had meetings with SolarEdge at their Headquarters in Israel. My opinions about SolarEdge optimisers have changed considerably, so I have updated this SolarEdge review to reflect.
Part one and two are a condensed version of my original review. In part one, I explain the SolarEdge inverter theoretical advantages. In part two, I pull apart SolarEdge’s newest model, the SolarEdge HD Wave.
Part three is where I address the problems I have observed with SolarEdge. On Christmas Eve of 2018 at 3:15 pm, I received a letter from SolarEdge lawyers. The letter demanded I remove Part Three of this post. Instead, I amended Part Three to address their concerns, and I added lots of bonus updates. Major changes are in blue.
Before I start, I need to make it clear that my comments are based on my personal observations and experiences with SolarEdge viewed in the context of my work in the industry and my dealings with other comparable and competing products. While I talk to and receive feedback from a lot of people in the industry, I have obviously not conducted world-wide testing or customer surveys – I am talking about what I have seen and how SolarEdge products have performed in the installations my team has installed. I am happy to give credit where credit is due but will also identify problems as I see them. I have no issue with SolarEdge as a company and any criticism is designed to be constructive. I am always prepared to update reviews if I receive additional information or new generation products come onto the market.
One of the purposes of my blog is to highlight the good and not-so-good aspects of the products I deal with so manufacturers and designers can understand what is working well in Australian conditions and what needs more attention. Hopefully, this will help them continue to make improvements. That is in everyone’s interests.
THE MAIN UPDATES ARE IN BLUE FONT.
SolarEdge is a huge player in today’s solar inverter market. Compared to their competitors, they are the new kids on the block. They only kicked off in 2006 with the first inverter sales in 2010. Today they are second only to SMA for the number of residential inverters they are moving, and the way I read it, they have been successful are making money hand over fist. So what are they doing right?
To step back a bit, let’s look at one of the key components of any solar inverter: the Maximum Power Point Tracker (or MPPT). Standard string inverters have two MPPT’s. The panels on a house are divided into two groups (or strings) and connected to the two MPPT’s in the inverter. As the sun’s intensity changes throughout the day, the two MPPT’s will continually adjust the voltage and the current from the panels to achieve maximum power.
The potential problem with standard string inverters is that a string of panels works kind of like old school Christmas tree lights: if one panel is affected by shade, then all the panels in the string are affected. The SolarEdge Inverter offers one solution to this problem. It takes the MPPT’s out of the inverter and effectively puts one MPPT (or optimiser) behind every panel. So if one panel is shaded, it does not drag down the performance of the next.
I deliberately didn’t call this section “enhanced safety” or “SafeDC” as SolarEdge brand it, because that infers other solar systems are not safe. If solar systems are installed by electricians who follow today’s standards, your solar is arguably as safe as the rest of the electrical wiring in your home.
The nature of electricity is that it is not 100 per cent safe, but we can put measures in place to make it safer.
Optimizers and microinverters offer a solution that brings another level of safety. SolarEdge’s optimisers require communication with the inverter in order for them to operate. If the SolarEdge inverter is turned off, the optimised panels will produce a safe 1 volt each. This would prevent solar contributing to your house fire, and the firefighters will appreciate that you used a solar solution that enables rapid shutdown.
SolarEdge Inverter Monitoring
Every system we install today has an in-depth level of monitoring. SolarEdge is one option that allows you to monitor every single panel’s production. Seems overkill? Here’s why you may think you want individual panel monitoring.
i) To identify shading for tree growth and soiling,ii) to identify panel degradation, (this point is dampened in Part Three under “can optimisers underperform”).iii) to identify bypass diode failure, and,iv) education. Because there is always more to learn about solar.
In the earlier version of this post, I rabbited on about each of those points. However, while all these features are available on SolarEdge inverter monitoring, I now question their accessibility and their reliability. I discuss that in Part Three. But for now, let’s look at the positive and check out the HD Wave Inverter.
SolarEdge inverter specifications
In the early days, inverters used a heavy copper-wound transformer. Over the last ten years, inverters became “transformerless” which made them heaps lighter and more efficient. All inverter manufacturers today use SMA’s H5 Bridge technology – all except … the new SolarEdge inverter.SolarEdge claims to have lifted the bar. They have replaced electrolytic capacitors with film capacitors and heavy magnetics with digital processing. There are three claims that SolarEdge makes that I’ll examine. In this updated version of my blog, I have abbreviated my original findings.
i) The HD Wave is more efficient.
In theory, I proved this to be correct in my original testing. But, read on to Part Three. It’s a bit more complicated than I understood in my original tests.
ii)The HD Wave produces less heat and requires less cooling.
Again, this was proven correct by my original testing. However, in my experience, this hasn’t necessarily translated into longevity compared to Fronius.
iii) Film capacitors last longer than electrolytic capacitors.
SolarEdge has claimed electrolytics only last an average of 10 years, and by using film capacitors they significantly increase the expected life of the inverter. I consulted leading inverter manufacturers.
An anonymous comment from a well-respected figure was pertinent:
If correctly specified and chosen, and an inverter’s internal heat dissipation properly designed and tested, electrolytic capacitors have no problem to continue to operate for a product design life of 20-25 years. But the same is of course true for ANY component within an inverter.
I contacted SMA, ABB, Sungrow and Fronius. Each had similar statements.
The ugly inbuilt DC Isolator
Design counts. The version of the SolarEdge inverter that was on display at Intersolar in Germany looked small and schmicko. Australia, however, has this stupid regulation about inbuilt DC isolators that made SolarEdge feel obliged to favour function over form.
The isolator works fine and I’m not doubting that it is ‘fit for purpose’. It just feels flimsy. You get the vibe that the engineers snuck it past the design department to get it to market in a hurry.