Tesla Powerwall Compatible Inverters

Mark & Fin Peacock with the PowerWall – Melbourne 2015

Powerwall Compatible Inverters

Since Elon Musk made his huge (albeit premature) announcement about the Tesla Powerwall, it seems everyone wants to be Tesla ready with a compatible solar inverter. There’s two for review on the Australian market: the Fronius Symo Hybrid and the SolarEdge. I’ll talk through both inverters. Beware, if you are looking into the SolarEdge: only the latest model StorEdge inverter will run off grid.

The Fronius Symo Hybrid

Fronius Symo Hybrid Specs

There is so much to love about Fronius. I first reviewed the new Fronius when I discovered it earlier this year. Since then we have installed over two hundred Fronius Primo and Symo inverters, and we have one running on test in my office/showroom. Fair to say my opinion is based on experience.

• Design Flexibility. Fronius’ voltage and current range offer a much-needed design flexibility. A feature overlooked by other European inverters like SMA and Bosch. Its dynamic peak manager makes its MPPT even more responsive in part shade.
• WiFi. It’s because you are not interested in WiFi – and all that fancy stuff – that WiFi matters. At very least, we’ll both get email alerts if something in your system goes wrong. It’s there for if your power bill comes in a little higher than expected. We can check your system’s performance from online and diagnose remotely. Its WiFi is rock solid and it’s interface so simple, that we may even be able to get you interested in opening an app on your iPhone occasionally. The interface leaves ABB for dead.  SMA and Bosch didn’t even come to the table.
• Online Platform. The Fronius Solar Web Platform has lifted the online monitoring standard to a whole new level. It’s easy to use for the novice and the detail that the electrician can drill down to will be an invaluable tool. As an example, it has alerted us to several high grid voltage problems that would have otherwise gone undetected.
• Solar Diversion. This one is a huge! It’s add-on smart meter, and external contacts allow you not only to see your consumption and production overlaid but also allows you to divert that power to another appliance (e.g., your hot-water system or pool) instead of sending excess power back the grid!  Genius.
• Quality build. It’s a big heavy unit, and the visible build quality gives me assurance that it is built to outlast its attractive introductory 10-year warranty.
• Serious about batteries. Gunter Fronius started Fronius in 1945 making automobile battery chargers. They know how to charge a battery. As an attractive option to Tesla, Fronius’ own Solar Battery combines Sony battery cells and Fronius’ battery charging software. Volker from Fronius explains it is their knowledge on how to charge and discharge a battery that is key to its massive 7000 cycle capacity. From 4.2 kWh to 12 kWH, it is available right now.
• Seriously hybrid. With soon to be released software updates, the Fronius’s hybrid inverter will run when grid power is down. It will also be able to take a secondary AC power input should it need to. It’s multi-flow technology and smart grid capability are features that you didn’t know you’d need in the battery revolution. That’s why you leave it to Fronius.

Here’s the catch. It’s only the Fronius Symo Hybrid that is Tesla Powerwall compatible. The Symo is a three-phase inverter. If you have three-phase at home, lucky for you! If you are currently building, get your sparkie to install 3 phase. This will be one sweet set up with the Tesla – and probably even better with their own battery. If however you only have single phase and are dead-set on the Powerwall, you could go to the expense of getting 3 phase – or keep reading.

The SolarEdge / StorEdge

While I was waiting for SolarEdge (SE) to be price competitive and to prove itself, SE was waiting for Battery technology and regulations to catch up with their technology. All four met fortuitously (at least in my small mind) at “All Energy” in Melbourne in October 2015. In a nutshell, SolarEdge has it all:

SolarEdge has some advantages over a string inverter.

(Keeping in mind SolarEdge is 6 years old, Fronius is 69.)

• It allows panels to operate individually – shading, dirt, and degradation will not affect a group of panels.
• It runs extra low voltage (about 30v) through each panel, reducing panel degradation.
• The voltage through the ceiling cavity will turn off in the event of a fire (when the power is turned off.)

SolarEdge is Better than a Micro Inverter

• It does not have all the hard working parts on the roof – including capacitors.
• It does not have the regulation and design restrictions of Micro-inverters.
• I discuss the Solar-Edge and Micro-inverter comparison in more detail in this blog.

Battery Compatible

• Solar Edge inverters installed today are designed to work with the Tesla Powerwall, however, you will need the StorEdge interface for about an additional $1500.
  Storedge interface Specs
• Solar Edge inverters coupled with the StorEdge interface will not run off grid – this is a major downfall, however…
• A new release in May 2016 is the Solar Edge’s StorEdge Inverter.  If you buy the StorEdge (rather than the SolarEdge inverter, it will come with the battery charger built in, and it will run off grid.
  StorEdge inverter Specs
• Solar Edge / StorEdge does not have an AC input for a second generator as does Fronius.
• Does not have its own battery solution as does Fronius.
• The 3 phase version cannot be used in residential premises because of it’s high DC voltage (750 VDC).

Redback Technologies

Rumour has it that Redback Smart Hybrid System will be Tesla ready in December 2015.

(UPDATE 22/3/16: Redback read my negative review and challenged me to visit their facilities at UQ to give me a better understanding of their inverter. It is not Tesla compatible, but it one impressive unit. Read my review of  Redback Technologies here.

The fourth?

Watch this space. Everyone wants to jump on board the Tesla bandwagon. If you know of more Powerwall ready inverters that I have missed, leave a comment, and I’ll add it in!

SolarEdge or Fronius?

So for now if you want the Tesla Powerwall battery, we are stuck with two – but two outstanding inverters. Which is right for you? If you have single phase the choice is made up for you, go SolarEdge. If have three phase in your home and you need a three phase inverter, go Fronius. If you have a three-phase supply but don’t need a three phase inverter (or you are looking for a commercial property)  It will come down to your individual situation and personal preferences. Either way, you will be picking between the two best inverter systems on the market, and they will both be ready to roll with Elon’s new PowerWall as soon as it hits our shores. Contact us for a more detailed discussion about which inverter will best suit your needs.

Mark Cavanagh