Thoughts on Solar

On Tuesday, August 11, 2020, Enphase sent out a notice to its top installers alerting them that starting in December, the Ensemble Storage System would support earlier generation microinverters and not just the IQ series as had been originally announced.  We contacted Enphase to learn more, and here is our report…

Some Background…

Last November we wrote about the coming Ensemble rollout.  In describing how Ensemble could be incorporated with existing systems we wrote:

First, you need to have IQ microinverters.  At least as of the initial rollout of this system, the older microinverters are not supported.  That means that the M and S-series of microinverters have to be replaced to IQ-series microinverters to work with Ensemble.  (I do not know if this will change in the future, but it is the guidance that we are getting at this time.)  It is possible that there will be some sort of replacement program (like Enphase did with the legacy M-190 customers), but I have not gotten any word about such a plan yet.

As we were told by Enphase CEO, Badri Kothandaraman, at SPI last year, it was important for Enphase to focus on a successful launch of Ensemble, and the way to do that was to concentrate on pairing it with the more capable IQ series of microinverters.  It had been disappointing news, but understandable given the challenges of bringing a product as technically sophisticated as Ensemble to market.

So I was more than a bit surprised when I saw the announcement from David Ranhoff, Chief Commercial Officer at Enphase, that Ensemble would be able to support M215 and M250-based systems as of December!  Of course this raised nearly as many questions as it answered, so I reached out to Enphase for more details.  

What We Know Now

I was able to speak with Utsav Ghosh, Senior Product Manager, about the details behind the announcement.

Our first question was: What about the S280’s?  They are more capable than the M-series, so are they included?  Sadly, no, not at this time.  Given that the M215’s and M250’s are the largest segment of the non-IQ installed base, they generated the greatest number of inquiries, and so they got the staffing attention.

I remarked that given the relatively short window between when Ensemble was available for the IQ micros and when it will be available for the M-series, why not just say that they would be supported.  The answer, it seems, is that in refining Ensemble, they realized that it would be easier than previously thought to fold in the M215/250’s.  This, of course, gives me hope that the S280’s won’t be far down the line.  Squeak, squeak!

Enphase M215 Microinverter is Eligible…	As is the M250 to work with the Ensemble Storage System!
Alas, the S280 is out of the picture, for now!

Our next question concerned communications - the M-series micros communicate via Power Line Communications (PLC) via the neutral and hot conductors.  The IQ-series does not bring a neutral to the roof, so it communicates PLC from hot to hot.  How does this get resolved?  

Turns out quite easily, assuming you have an Envoy-S, like the one on the right.  So how do the IQ8 microinverters in Ensemble communicate with the Envoy?  As it turns out, the same way that they do in an IQ system - via the add on Comm Kit that adds Zigbee capability to the Envoy-S.  The even better news is that Comm Kit is part of every Ensemble Storage System, so there is no additional cost for M-series systems over IQ systems!  Yay!  (The Envoy-S will need a new software version, but that is a free download.)

Our next concern had to do with speed issues: the M-series micros just aren’t anywhere near as computationally powerful as their IQ cousins.  Would the seamless backup functionality promised with the IQ series still apply?  Yes, we were assured.  Cool!

Which brought us to our final question: What ratio of legacy inverters to IQ8 inverters will be needed to allow the microgrid to operate?  Recall that with the IQ series we are presently being told that the ratio is 1.5:1, that is, an Encharge 10, that has 12 IQ8 micros inside, can support up to 18 IQ 6 or 7 micros on the roof.  (While we are hoping to see some movement on that front, that is the present design guidance.)  So what will the ratio be for the M-series?

Great question - no precise answer as of yet, other than “it will be more restrictive."  There is testing ongoing to establish precisely what those limits are, which is why the availability is being cited for December and not now.  Obviously we will be following this closely and will update you when we know more, watch this space!

I want to thank Utsav Ghosh for being so responsive and generous with his time.

And I especially want to thank Enphase for responding to the cries of their clients in getting this much-needed functionality addressed.  Great job, folks!

Now about those S280’s…