Thoughts on Solar

I suspect that most of my NABCEP-Certified colleagues have had this happen - you are on your way to a jobsite when you pass a solar installation that is so painfully bad, that it stops you in your tracks and you just have to go and take a closer look at what happens when Shortcut Solar has botched another job. Follow me into a realm where you never want to find yourself, the horrifying reality of Shortcut Solar at work!

Wow, there’s a lot going on there and none of it good.  The panels on the left are facing a variety of trees.  The panels on the right have a significant pitch-up to the south, with a lot of exposure to the wind out of the north.  The cable management there appears to be: let it just hang down.  That middle section is supposed to have 18″ of clearance at the hip given the panels on the adjacent face, but they are actually overlapping the hip!  And how exactly are these attached to the roof?  A closer investigation was in order!

Seriously? Looks like old Shortcut was in a real hurry the day they did this job!  There is a rail there on the high end - surely you could have found some way to use that to get those cables in order - but clearly that wasn’t a priority!

But it was this last image that really got me going.  Checkout this attachment scheme:

I apologize that the image isn’t too clear, but let’s try and break down what is going on here.  At the base in the foreground you can see what appears to be a 3″ or so piece of unistrut that has been cut to length and painted black.  There is no flashing of any sort visible here.  Instead, the strut has apparently been bolted directly onto the roof.  Perhaps those clever fellows from Shortcut Solar drilled pilot holes and squirted in some sealant?  Or maybe not - I mean why go to all that extra effort?

So that’s your attachment, now for the standoff - I know, how about a threaded piece of 3/8″ steel?  You can attach it at the bottom with a channel nut, and then just drill a hole in your aluminum rail and secure it with a nut above and below!  What could possibly go wrong?

Well let’s start with the wind.  When the Santa Ana winds blow out of the North, they will rock those panels, and that long, skinny bolt will flex with the wind.  It is steel and the rail is aluminum, which means that the steel, over time, will chew into the aluminum.  Enough flex over enough time, and that attachment scheme is going to fail - potentially in a catastrophic manner.

(Wanna see what happens when steel defeats aluminum on a roof in the wind?  Check this out!)

 It should come as no surprise that there is a better way to do this!  Here’s our preferred approach:

The picture on the right shows one of the strongest possible combination of solar attachment components you could ask for.  The rail and L-foot comes from Everest.  The 3-inch standoff is from Unirac and the flashing is from Oatey.

Under the flashing is a rounded-rectangular base plate that accepts two, 5/16″ x 3 1/2″ lag bolts.  Two lag bolts gives you twice the strength, and hedges against hitting just the side of a rafter, or a possibly rotted/weak spot.  The 3-inch standoff screws down onto the base, and the Oatey flashing goes over it all, insuring that it will not leak.  The L-foot is bolted to the standoff and is in turn bolted into the rail - which was engineered to accept this configuration.  All components are torqued to the manufacturer’s specification, and marked to indicate that the torquing was performed.

Does it take longer to do things that way?  To be sure.  Does that mean it costs more to do it this way?  Of course.  But ask yourself, which of these approaches would you want on your roof?

We take pride in doing things the right way for our clients so that they can sleep well at night, no matter how hard the wind blows!

And we will continue to brake for Shortcut Solar and call out his subpar work whenever we see it so that you, a solar homeowner, will know what to look out for when you choose a solar installer!

I just returned from two days of hands-on training with the new Ensemble Storage System from Enphase Energy at their HQ in Fremont, California.  Here’s my take…

Ok, to say that I have been somewhat obsessed over the Enphase IQ8 and its incarnation in the Ensemble Storage System over the last year and a half would be an understatement, having written about it here, here, here, here and here!  I’ve attended webinars and conference sessions where Ensemble was discussed and the technology explained.  But like any good installer, what I really wanted to do was get my hands on these devices, wire them up, and get a real feel for what it takes to put these on a client’s wall.  This week I got my chance!

Here is one view from the lab at Fremont.  On the far left is a main service panel and meter. To its right is the Enpower Smart Switch which acts as a Microgrid Interconnect Device (or MID). Next is the Encharge 10, alongside its smaller sibling, the Encharge 3. 

(As this image suggests, Encharge 10 and Encharge 3 can be combined as desired to achieve the combination of energy storage and power output required.) 

Next is the IQ Envoy Combiner (not new, although it now comes with a cellular modem standard).

Finally, there is the simulated array made up of IQ6’s and IQ7’s (both regular and Plus versions).  Out of the field of the picture is a PV array simulator that powers the microinverters.

Oh, and no demo would be complete without some loads, including a light, a microwave, and an electric stove - all of which were powered by this system with the grid disconnected.  (Some people have asked how fast was the switchover - so fast that the light doesn’t blink and the clock on the microwave did not reset.)

Over the course of the two days we spent a lot of time in the classroom - headed by Peter Lum, trainer extaordinaire - focusing on the nitty gritty.  How do you size an Ensemble system, how do you mount these things, how do you wire them up, how do you comply with the electrical code?

Our lab time on the first day was a demo of the system on the wall.  The second day, we were actually mounting these to the wall and wiring them up.

Getting Our Hands Dirty

I’ve already written a lot about the specs of these devices, so I won’t repeat that here.  The point of this post is to discuss the actual installation process.

On the left is the Enpower with its deadfront removed, alongside the Encharge 10 with its cover removed.  (The whitle, L-shaped pieces on top of the Encharge 10 cover are the screw down covers for the Encharge’s wiring compartment.)

Encharge 10

Let’s start with the Encharge 10 - as the photo makes clear, Encharge 10 is actually three Encharge 3’s mounted on a common mounting bracket.  Each Encharge 3 includes four IQ8 microinverters, and they are individually replaceable, so should one ever fail, the others continue to operate and the monitoring will advise the installer of which unit has failed.  All the field technician needs to do is remove the cover, disconnect the failed microinverter, plug in the replacement, and put the cover back on. Moreover, because the micros are on a common bus inside the Encharge 3, if one should happen to fail, you still have 75% of your total power, but 100% of your stored energy!

An Encharge 10 constitutes a 20 Amp branch circuit, and up to two Encharge 10’s can be wired together in series (maximum wire size is #8).  If a larger storage system is required, then the Encharge units need to be landed in a dedicated subpanel.  (The Enpower is rated for up to 80 Amps of storage.)

To the left of the IQ8s is the battery management unit and the battery disconnect switch.  (Not really visible in this picture is a status LED that shows whether the battery is on or not, whether it is idle or charging, and the relative state of charge as it shifts from blue (discharged) to green (charged).

The finned area is the actual LFP batteries themselves.  All cooling is passive, no fans are involved.  The unit needs to be mounted a minimum of one foot from the ground, and if you have more than one row, at least six inches (vertically) between rows.

The mounting bracket is secured to the wall with sufficient hardware and into sufficient structure to support the total weight of 346 pounds.  (Enphase will be releasing a white paper on best mounting practices - a must read to be sure!)  Each individual Encharge 3 is then lifted onto the bracket.  Given that these are over 100 pounds, this is a two-person lift to be sure!  My colleague Greg and I struggled a bit with the lift, mostly because I wasn’t really pulling my weight - so to speak.  (My value add isn’t really in lift strength!)  But the younger guys that were in the training with us managed the task with ease - ah youth!

The Encharge 3’s are then daisy-chained together in a wiring compartment at the top of the units, as you can see in the picture on the left.  Each terminal block can hold two wires, one coming in, one going out.  The last unit just has the incoming connection and no other termination is required.

Note the black piece connecting to the two units.  That is a plastic, snap in conduit section that is added after the units are mounted.  The last unit in the chain has a rubber plug in that opening to keep the wiring compartment watertight. 

(Note, the section with the microinverters is not watertight as the IQ8’s are NEMA 6x, which means that they can - and are tested to prove it - operate under water!)

Once the wiring between the Encharge units is complete, the unit closest to the Enpower is then wired to it, and then the tops can be screwed on, and the cover added.

Enpower

Which brings us to the Enpower - which is both a MID and an interconnection center.  Note, however, that Enpower is not a general purpose panelboard, but rather, a specially listed UL device and as such, the 120% rule does not apply.  As a result, the Enpower will accommodate up to 80 Amps of PV input (i.e., a fully populated IQ Combiner) and 80 Amps of storage input (i.e., four Encharge 10’s.)

In the picture above, the input from the meter (if serving as a whole-home backup system) or the the main service panel (in a partial-home backup) comes in on the right hand side.  In the picture there is an Eaton main service, bolt-down breaker installed.  If this were intended for a partial-home backup with a breaker in the main service panel, the Eaton breaker could be omitted and the input conductors would land on the existing lugs.

Directly above that main breaker is the isolation relay, which trips when the grid fails and isolates the system for creating a microgrid.  Above and to the center is the neutral forming transformer that allows the system to power 120 VAC loads.  Below that on the left is the common bus that holds (going counterclockwise from the top left) the breaker for the PV, the breaker for Encharge, a breaker for a generator (but not yet), and the breaker for the neutral forming transformer.  

You can see the conductors for all of those connections pre-wired in the photo, waiting to be attached to the appropriately sized breaker.  The actual connections for both the PV and Encharge are made on lugs at the very bottom.

The output to the loads is at the base of the common bus where an appropriate Eaton breaker is added.  Fun fact - the Eaton service rated breakers actually swap L1 and L2 from one side of the breaker to the other!  This means that installers need to pay attention to their phasing so that the consumption and production CTs are reading the proper values - a topic we discussed in some detail in the classroom, and then verified in the lab - damn, isn’t hands-on training the best!

The Enpower switch, the Encharge units, and the IQ Envoy Combiner all communicate directly via Zigbee.  In fact, each unit has two radios, one at 2.4 GHz and the other at 900 MHz and the units switch automatically between channels and frequencies as necessary to provide the clearest signal.  Moreover, if the Combiner box is remote from the Enpower but closer to Encharge, the Encharge unit (or vice versa) can serve as a repeater to get signals to the other devices.  Pretty clever.

Providing Feedback…

Of course, there are two purposes to a training like this during a beta period: to get the initial installers up to speed with the product, and for the installers to provide Enphase with feedback.  Along the way we discovered a diagram that was wrong (nice pickup, Greg!), and a couple of places where esthetics got in the way of utility.  Those are easy things to correct, and Enphase’s CEO himself came into our classroom to hear our feedback directly!  That is a level of dedication to hearing what the long tail has to say that just isn’t happening with other solar companies.

Finally, a point of personal privilege: some years ago we did a video about our installation at Westridge School for Girls here in Pasadena (you can find it here.)  Well what do you know but that video is part of a loop that is playing in the Enphase lobby!  One of the engineers actually came up to me and exclaimed, “You’re the guy in the video!"  Fun way to end our two days at Enphase HQ. 

Bring on the Beta!

Some product announcements make a big splash - think the whole Enphase Ensemble product line which is sure to be a game changer.  But other products are far more subtle in their impact.  They are, in this case literally, invisible to our clients, but we love them because they make a part of the process so much better.  Such a product is the “Yeti” end-clamp from our friends over at Everest Solar.  Let’s look closely at a small but important product that you will never see!

First off, what even is and end-clamp?  When solar panels are mounted on a pitched roof, as most of them are, we put attachments down that lag into the rafters and are flashed.  On top of that go the rails, with the panels sitting on the rails.  Mid-clamps go between the panels to anchor them to the rails, and end-clamps mount at the end of the rail to secure that last panel.  The design of end-clamps is far tricker than that of mids since the mid-clamp rests evenly on the two panels. But the end-clamp only has one panel to grab, making it tricky to get the alignment just right.  Indeed, it is so hard to get it right, that when Unirac phased out their wonderful Solarmount Evolution line with its awesome end-clamp, we penned an open letter to Unirac management, begging them to reconsider.  (Alas, to no avail.)

Most end-clamps hold the panel by pushing down from the top of the panel.  However there is one major drawback with that approach - an overzealous installer can blow past the torque wrench setting and end up shattering the panel!  Ouch. 

But check this out:

The Yeti clamp is highlighted in the circle callout, and you see it in red, sitting in the rail channel, and gripping the lip of the panel frame pressing it against the rail.  (You can see a quick install video here.) The resulting grip is super-strong, and the clamp is completely invisible, allowing you to cut the rails right to the edge of the panel frame.  This gives you a secure, super-clean looking install.

We got our first chance to use these on an install last week and we are really pleased with how things turned out!  (This was an unusual install for us in that the second half of the panels got installed in the rain - an everyday occurrence for our installer friends up in Oregon, but a rarity down here in sunny SoCal!)

Here’s how the array turned out:

So first, notice the water drops on the panels!!!  But the second thing to notice is just how clean a line we have at the edge of the array.  (You can see the mid-clamp in the small gap between the panels.)

Here’s another view, right down the edge:

Doesn’t get much cleaner than that!

So we are convinced!  For an extra 20¢ a piece, we can have a better gripping clamp that is completely invisible and allows you to trim the rails right to the edge of the panels, giving you the cleanest possible look!

Let’s hear it for those small, incremental improvements that make the solar industry such a great place to work.  Big or small, invisible or super flashy, the innovative minds out there are continually striving to make our systems better for our clients.  And that’s as it should be!  Nice job, Everest!

[Editor’s Note: Today is Veterans’ Day, so a shoutout to our Vets: Victoria and Greg,
and to all the Vets out there - thank you for your service to our country.]

The Enphase Ensemble system is almost here, so let’s start talking about how this is going to work for existing and potential clients.

What is Ensemble?

Ensemble is the name of the new Enphase storage and control system.  It consists of the Enpower smart switch, some amount of Encharge battery systems (depending on your needs),  and an IQ Envoy to handle communications.  The system is capable of supporting “whole home” backup, although for most clients a “partial home” system will make more sense.

Enpower Smart Switch 19.7″ x 36″ x 9.7″ 80 lbs.		Encharge 10 kWh Storage System 42.12″ x 26.14″ x 12.56″ 346 lbs.

The Enpower smart switch contains an automatic transfer switch - or a Microgrid Interconnect Device, to use the language of the NEC (to isolate from the grid when there is a grid failure) - rated at 200 amps, and a neutral forming transformer to allow for 120/240 VAC operation.

The Encharge batteries come in two sizes: a 3.3 kWh battery and a 10 kWh battery (which is actually three of the 3.3 kWh batteries mounted behind a common cover).  Inside the 3.3 kWh unit are four IQ8 microinverters, and thus 12 as part of the 10 kWh unit.  The 10 kWh unit, which is going to be the minimum size that you will want, has a continuous output power of 3.84 kW, with a peak out of 5.7 kW for ten seconds - enough to allow for inrush current from motors, for example.

Both units have a NEMA 3R rating so they can be installed outdoors (though you will want them out of direct sunlight if possible), and come with a 10-year warranty.

How Will it Fit with My Existing System?

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.

Second, you need a rough parity between the output power of the solar array and the output power of the Encharge batteries.  That means that if you have a single, 10 kWh Encharge battery system, the rated output power of the installed microinverters on the roof, has to be at or below 5.7 kW.  Here’s what that means for the IQ microinverters that have been installed in the past three years:

As the systems that we have been installing have all been IQ6+ or IQ7+, you can see that with a 10 kWh Encharge system, you are limited to 19 panels - a 6.365 kW system when paired with LG 335’s.

How can I Plan to Make Ensemble Work Best for Me?

Making this work requires some planning and modifications, and not every existing system will be a good candidate for this.  As we have noted in earlier posts about Ensemble, most folks in Southern California have what is called a combination service panel where the meter unit and the distribution unit (where the breakers are) are in the same, physical device.  Without replacing the service panel, you are left with a configuration that will looks something like this:

That is your PV system in the top left powered by IQ microinverters.  Those land on an IQ Combiner (which Run on Sun has been using since the IQ microinverters were rolled out).  On the far right is the grid, feeding your meter and the service panel.  (In an existing system, the output from the IQ Combiner goes to a disconnect switch and then to a breaker (or a lug) in the service panel.)

To add Ensemble, you need to connect the Enpower switch to the service panel via an appropriately sized breaker.  You also need to create an emergency load subpanel, with the critical loads that you want to operate during an emergency.  (This takes a good deal of thought - you will need to know the power requirements of the devices you are looking to operate during the outage and size the system accordingly.)  Everything then flows through the Enpower switch (including the possibility of a backup generator, though that will not be immediately supported).

We do not yet know what the utilities or local AHJs will say about this.  Presumably the utilities still want a lockable disconnect switch on the output from the Combiner, but will they also want one on the output of the Encharge battery system? The Encharge system allows for two, 10 kWh units to be “daisy-chained” together; for larger storage system a storage subpanel is required.  Also required is consumption monitoring, which may not be possible on some service panels (due to space constraints) without rewiring the entire panel - ugh.

So… this is going to be a great product, but it is neither a cheap nor simple process.  Interested?  Let’s get started!

And sad to say, we lost this one!  (The election to be on the Board of the California Solar and Storage Association, that is!)

But I am honored by the support of so many of you, and you can count on me to continue be a vocal advocate for this industry – and for doing things the right way.

In the meantime, here is the list of the winners this year:

Contractor Seats
Ed Murray, Aztec Solar
Gary Gerber, Sun Light & Power
Keith Randhan, Baker Electric Home Energy

 Manufacturer, Distributor, Developer, Financier Seats
Catherine Von Burg, SimpliPhi Power
Yann Brandt, Quick Mount PV 

Congratulations to them all - here’s to a very productive term of office.