Upgrading Our Solar PV System

We have had a 2150 watt grid tied solar PV system since 2009 and it has performed well. Lots of detail on the old system here...

We decided to bump up the size of the system to 5000 watts and at he same time make some upgrades to the system.

The reasons we decided to do this ...

  • The old 2150 watt system was falling short of our monthly usage.
  • Enphase is offering an attractive upgrade to their newest design microinverters for customers with older inverters.
  • Montana is in the process of changing the net metering rules with existing systems being grandfathered in under the existing rules.
  • We would like to have a system large enough to meet our needs and also to provide at least part of the juice for a future plug in hybrid.
  • We want to take advantage of the 30% federal tax credit while its still in effect.
  • The price of solar has fallen significantly making the economic payoff much more attractive.

The old system consisted of ten panels mounted on the ground in a single row-- the new system just adds another nearly identical row of ten panels to the south of the current row and located just far enough away that the new panels don't shadow the existing panels. The old panels are 215 watts each while the new panels (which are the same size) are 285 watts each.

This page covers what was involved in the upgrade and expansion.

 

Enphase Legacy System Upgrade Offer

Enphase has an offer out to allow owners of older system to upgrade to the latest IQ7microinverter at a discount. The upgrade includes replacement microinverters, new cabling, and a new Envoy unit. Total cost for our existing 10 miro inverter system was $675. For our 10 micro inverter system this would be close to $2000 at retail, so a pretty good discount.

Our old system was working fine, and still had years of warranty left. But, the fact that they were offering the upgrade made me a little uneasy about the long term durability of the older micro inverters.

The upgrade also made it a lot easier to add the additional capacity to the system in that all of the microinverters would be the same IQ7's, rather than mixing our old inverters with the new inverters which would have required two Envoy units.

Another nice thing about the newer micro inverters is that they allow an Enphase battery units to be added. The batteries provide for power if there is a power outage. We decided not to add the batteries for now, but its nice to have the option. Most grid-tie systems do not allow for operation during a power outage.

The new cabling system is lighter weight and very easy to hookup.

Adding the New Array Supports

We decided to use the same kind of arrangement to support the new bank of 10 PV panels. We like the wood look and simplicity andsimpleuncluttered look of it. So, we just duplicated the existing PV panel support structure about 25 ft to the south. The space between them insures that new panels will not shade the old ones.

There were some doubts expressed about the life of the treated wood supports, but our existing one looks just fine after 10 years with no sign of problems. This may be in part due to our dry climate.

Supports for the new 10 PV panels -- same as the old one.

 

Footing for one of the supports. The grey wood is a temporary support that I ran across the back of all of the supports to make it easier to insure all the supports were lined up.

Another view of the temporary (grey) support beam to align the supports while the concrete was setting.

 

And anoter view -- At this point only the end supports are in place, four more intermediate supports were added (you can see the footing holes). The supports are sloped at 45 degrees (same as the orginal ten panels). It is important to get all the support frames carefully aligned as the adjustment in the Ironridge rail attachments is limited.

Ironridge Rails

We also decided to use Ironridge PV panel support rails that are the same as the rails on the old system.

Ironridge has come up with new wrinkles on the clamps that are used to hold the PV panels to the rails. The new design is easier to use in that the bolts have a T head that slip into the channel in the rail anywhere - so, you don't have to slide them all in from the ends of the rail before putting the PV panels on. The new clamps also stand up in the rail slot, so it does not take three hands to place the PV panels.

The new T bolts also have serrations that insure a good ground connection between the PV panel frames and the Ironridge rails. This means that you no longer have to use Weeb washers or a separate grounding wire to ground the PV panel frames.

I do like the whole Ironridge system.

Upper PV panel support rail installed.

The IronRidge rail extrusions bolt to the wood support using L brackets that IronRidge sells. There is some adjustment available via the slotted holes in the L brakets.

 

Closeup of an L bracket.

 

The new Ironridge fitting that clamps the PV panels to the rail extrusion. Easier to install than the old design, and they provide grounding as well without the need to use Weeb washers.

 

This is the fitting used to anchor the end panels done. It is the same as the fitting used between panels, except that it has an added aluminium sleeve to replace the panel that would be on the left here.

 

This shows the PV panels being mounted on the IronRidge rails. Iclampedd a 2 by 6 guide along the bottom so that the PV panel could just be placed on the 2 b 6 while the inter panel clips were being tightened. Its important that the panels be properly aligned, and the 2 by 6 support makes this easy to do.

Installing Micro Inverters

For the old part of the system, I was able to remove the old micro inverters and install the new ones without having to remove the PV panels.

One of the enphase microinverters installed. The aluminum plate that is part of the inverter mounts to the same extruded slot in the IronRidge rail as the PV panels mount to. The new mounting bolts also provide grounding of the inverter to the rail (which may not even be needed as the new microinverters are double insulated). The install of the microinverters goes fast, with just one blot to tighten and a couple wires to plug in.

The new micro inverters are double insulated and (according to Enphase) do not require a separate grounding wire (as our old micro inverters did). The new T bolts that are used to mount the inverters have serrations that insure that the inverter mounting plate makes good contact with the rails, so are they do end up being grounded via the Ironridge rails in any case.

Wiring in the Second Bank of Panels

Since the 20 PV panels I now have exceeds the 16 panels that Enpase allows in one branch, I had to go to two branches, and each branch requires its own 20 amp circuit breaker where it ties into the house wiring. I decided to handle this by adding a new small sub panel out at the PV array -- this allowed me to use the existing wiring from the PV array to the house without having to add another set of wires fro the 2nd branch. So, each branch comes into the subpanel on its own 20 amp breaker and the sum of the two currents goes to the house over the wiring that was buried for the orginal PV system. I also used the new subpanel to mount a lightening surge protector (which gets its own 20 amp breaker as well).

The wires from the new line of PV panels go to the subpanel on the old line of panels via a trench and conduit.

Trench for the wires from new panels to subpanel mounted on the old ten panels.

 

The tractor helped save a little digging using a small single bottom plow, but was only able to get down to about 6 inches -- hand digging took it down to the required 18 inches.

This is the new subbox mounted where the junction box used to be on the original ten panel installation. The newly added lighting surge protector is the clear dome mounted on the bottom of the subpanel.

Inside the new subpanel. The two top 20 amp breakers are one each for the two ten PV panel branches. The lower 20 amp breaker ties the lightening protector into the system.

 

Envoy Communications

The Enphase Envoy unit takes care of reading data from each micro-inverter to see if it is healthy and how much power it is generating. It then sends this data over your INTERNET connection to the Enphase Server. You can then look at the page on the Enphase Server to see how your system is doing and how much power you are generating. The Envoy also reports non-functioning micro inverters to the Enphase Server, which then notifies you of the problem. The Envoy also (I believe) plays a role in updating the micro inverter software if needed.

The old Envoy unit was pretty simple -- about all you had to do was plug it into a wall socket, and connect to your router with an Ethernet cable. The Envoy communicated with the inverters over the power line and communicated with Enphase by plugging into your routers Ethernet socket. While it was simple, I gather there were a lot of problems, especially with the power line communications.

The new Envoy is more involved. It has to be hardwired to 220VAC close to where the PV system feeds into your breaker panel, and you have to add a new 220 VAC breaker for it or piggyback in onto an existing 220 VAC breaker. Another new feature of the new Envoy is that it supports the use of current transformers to more precisely measure both PV production and the home's power consumption. This is a nice feature, but does add more complexity to the Envoy installation.

This setup basically requires you to provide a new box near your breaker box to house the Envoy unit and conduit connecting to the breaker box for the power and Current Transformer wires. In our case, this had to be a weatherproof box as the breaker panel is mounted outside.

Enphase also provides an app for your phone called ToolKit that is used set up the Envoy and to scan in the serial numbers of each micro inverter, and several other setup related tasks.

After reading through the rather complex instructions to install and setup the Envoy, I decided to just hook up all the micro inverters and get the system working and producing power and then come back and get the Envoy working. It ended up taking most of a day to wade through all of the Envoy stuff, but it did come together in the end, and all the reporting stuff is now working and is nice.

I have to say that there were times during this day long Envoy install where I longed for the old simple Envoy. But, the new features of the new Envoy are impressive.

Something to be aware of for Enphase systems -- they draw a sharp line between the system "owner" and the system "installer". In order to do a DIY install of an Enphase system and get the reporting working you have to be the "installer", so identify yourself as such. Enphase does not appear to have any problem with DIY installs, so, you won't catch any static from Enphase if you tell them you are both the owner and installer.

The new Envoy is mounted inside the lower right box, which is weatherproof.

The Envoy mounted inside the box. The wires are for 220VAC power to the Envoy and the wires from the current transformers that are deployed inside the breaker box and provide both power production and power consumption numbers to the Envoy.

Closeup of the Envoy.

The Envoy reads data from the microinverters over the powerline and then sends this info back to the Enphase mothership via your internet connection. So, ideally, the Envoy should be in a location within your wifi network coverage (but they do provide some alternatives if you can't get wifi with your Envoy). The Envoy should be installed in a plastic (not metal) box in order to get good wifi.

A final thing to note is that the Enphase Tookkit software that you use to setup the system with Enphase also provides instaneous power production and consumption number -- this can be handy in that the numbers that show up on the Enphase site are delayed a few minutes. With the Tookit software, you can actually see the effect of turning the TV off in real time.

 

Power Monitoring

Enphase has new software that not only shows power production (as their old software did), but also shows power consumption. So, you can see not only how much power you are generating, but also how this compares to how much power you are consuming.

Based on a few days, it looks like on sunny September days, my prouction exceeds consumption by a good margin, so I'm hopeful that even with the lower winter production that we will come out about even for the full year.

Retailers

As for the original system, I ordered the whole system from Wholesale Solar. I have to say that it did not go as smoothly with Wholesale Solar as the first system did.

When the order arrived, all of the clamps that hold the PV panels to the Ironridge railing were missing. I contacted Wholesale Solar about this, and they promised to get a bid out for the missing parts right away, but after two weeks of emails and phone messages, no bid. In reading some of the online reviews of Wholesale Solar, I am not the only one experience poor customer support. I ended up ordering the missing parts from Northern Arizona Wind and Solar, and they were excellent and had the parts in my hands in 3 days flat. I was quite impressed by their customer support and speed. If I were doing another system, I'd definitely get a bid from them.

 

Comments

Please leave any comments on the upgrade on the orginal project page...

Gary

September 9, 2019