Enphase M190/M190IG/M215IG/M250 Head-to-head-to-head

Sorry for not linking to it directly. I meant the simple model like this: http://www.quickmountpv.com/products/composition-mount.html?cur=0" onclick="window.open(this.href);return false;

They end up being expensive even if you are doing 6' spans and get really expensive with 4' spans. I imagine the sealants these days are a lot better than a few decades ago I'm sure so that's good but it'll be very interesting to see how it holds up over the decades. The little custom L flashing that I've seen some people use when directly lagging the L foot seems to be a slight improvement as then there is also some physical barrier.

It'd be interesting to see installations from the dedicated people that were doing installations decades ago and what they used and how it's held up.

Certainly the roofing is going to be in much better condition under the panels.

All I know is growing up in a house that seemed to have a never ending problem with roof leaks from skylights, flat torch down down, and low pitch roofs I've grow to really really hate the idea of having a roof leak

QueenBee said:

Sorry for not linking to it directly. I meant the simple model like this: http://www.quickmountpv.com/products/composition-mount.html?cur=0" onclick="window.open(this.href);return false;

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That looks like a decent product! But I would have to ask whether there is a risk of an ice dam moving up the three inches to the point where the penetration occurs. The L-foot approach I used eliminates that possibility as long as the sealant holds. But I will grant that the effects of thermal cycling that they discuss might be real issues.

QueenBee said:

I imagine the sealants these days are a lot better than a few decades ago I'm sure so that's good but it'll be very interesting to see how it holds up over the decades.

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I have a hard time seeing the sealant fail in that amount of time given that it is completely protected from both sunlight and oxygen. But it does get fairly hot.

Frankly, the biggest concern I had with the L-feet is the possibility of over-compressing the foot into the shingles. My little impact wrench could literally drive the foot directly through the asphalt shingle. If any of the shingles got torn by over-torquing, that could create a real problem. I don't think that happened, but it certainly could have.

QueenBee said:

The little custom L flashing that I've seen some people use when directly lagging the L foot seems to be a slight improvement as then there is also some physical barrier.

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Personally, I think a flashing under the L-feet that I used would make them MORE apt to leak.

QueenBee said:

All I know is growing up in a house that seemed to have a never ending problem with roof leaks from skylights, flat torch down down, and low pitch roofs I've grow to really really hate the idea of having a roof leak

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I have had real issues with this roof starting when we moved into this house. Those were largely resolved with the high-quality roof we installed just before the PV went up. But there does seem to be a problem in an area away from where the PV is located. It's something I need to look into pretty soon. So far the PV penetrations do not show any signs of trouble.

Please join me in hoping this installation lasts for many decades!

RegGuheert said:

Frankly, the biggest concern I had with the L-feet is the possibility of over-compressing the foot into the shingles. My little impact wrench could literally drive the foot directly through the asphalt shingle. If any of the shingles got torn by over-torquing, that could create a real problem. I don't think that happened, but it certainly could have.

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Yeah, if you look at most of the torque specifications related to PV I think most of the concern is overtightening. When I took the first phase off to replace the roof there were definitely cases where the volts that slide in the chancels on the rails had been over torqueed and started to press into the soft aluminum.

QueenBee said:

The little custom L flashing that I've seen some people use when directly lagging the L foot seems to be a slight improvement as then there is also some physical barrier.

Click to expand...

RegGuheert said:

Personally, I think a flashing under the L-feet that I used would make them MORE apt to leak.

Please join me in hoping this installation lasts for many decades!

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I can't find a picture now but basically it's just a little piece of flashing in the shape of an L and the L foot and the flashing are back to to back so the water coming down the roof hits the flashing thus going around the L foot. It's just slipped up under the shingle up roof.

I'm not familiar much with having to deal with ice dams. I also put sealant in every predrilled hole before putting the lag in so that's plan B

Definitely hoping for no roof leaks! They'll not be fun with PV on the roof as it'll hard to find exactly where the issue is since there are so many possibilities that are all hidden

Phase II of the upgrade project is now mostly complete. I spent Sunday and Monday rewiring the outdoor PV array from its previous configuration of two subarrays of 48V each to 12 subarrays of 24V each. I also rewired the buried cable to the house from DC to AC. So far all nine of the PV panels from the roof are now installed in the field array and are producing. Finally, I have adjusted the tilt of the array to its summertime position, which is 15 degrees, IIRC.

Here is a picture showing production this morning:



Notice that the inverters in the field are producing more power than the inverters on the roof. This is because the array in the field is adjustable and it is currently more optimized for summertime production than the roof array. I expect the field array to produce more (per inverter) in the wintertime and summertime and the roof array to produce more in the spring and fall. This despite the fact that the array in the field is more than 10 years older than the roof array.

Also note that the top right inverter in the field array is producing just half of what the other inverters are producing. That is because one of the PV panels which should be driving is is damaged and needs to be repaired. Does anyone know where I can find a replacement terminal strip for a Solarex MSX-series PV module? Perhaps I just need to purchase a used module or two?

Here are some pictures of the installation. Click the photographs to see a larger version:







As soon as I have an opportunity (with some help) to replace three more inverters on the roof with the M215s I purchased, I can then add those three M190s to the outside array. I also still have some AC wiring cleanup to do inside the house for the field array.

My wife had an excellent idea! She suggested that we put some outlets out on the field array now that AC is available out there. I told her we would do that, but that will be done as a separate step since I did not have a service panel on hand on Sunday when I was wiring the AC on the field array.

RegGuheert said:

I told her we would do that, but that will be done as a separate step since I did not have a service panel on hand on Sunday when I was wiring the AC on the field array.

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Hi Reg,

Nice system. Your use of the phrase "service panel" confuses me a little, as the panel at the service entrance typically has a combined neutral/ground bar bonded to the chasis. At all points after the service, such as a panel at your solar array, the grounds and neutrals need to be kept separate. Of course, you probably know that but I thought it was worth clarifying.

Cheers, Wayne

wwhitney said:

Nice system. Your use of the phrase "service panel" confuses me a little, as the panel at the service entrance typically has a combined neutral/ground bar bonded to the chasis. At all points after the service, such as a panel at your solar array, the grounds and neutrals need to be kept separate. Of course, you probably know that but I thought it was worth clarifying.

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Correct. I should have said "load center" or "subpanel".

I like how simple (cost efficient AND adjustable!) your ground mount is. How's your snow load? Around here generally the minimum design is for 25 psf on up if you are in a heavier snow area. This ends up meaning that ground mounts are very stout. Posts at the top and bottom with lots of cross members, etc. For example: http://green.binarypeople.net/solar-phase-2-installation/" onclick="window.open(this.href);return false;

QueenBee said:

I like how simple (cost efficient AND adjustable!) your ground mount is.

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I also really like the design of that mount! But I paid someone to build it and install and wire the panels, so it wasn't cheap. I paid $4200 for all that 15 years ago (not including the PV!).

QueenBee said:

How's your snow load? Around here generally the minimum design is for 25 psf on up if you are in a heavier snow area. This ends up meaning that ground mounts are very stout. Posts at the top and bottom with lots of cross members, etc. For example: http://green.binarypeople.net/solar-phase-2-installation/" onclick="window.open(this.href);return false;

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Snow load is not an issue. That array goes to 60 degrees in wintertime and sheds snow very well. The real issue with that mount is WIND! That's why I paid so much to have it done. We have massive winds in the wintertime and with the array nearly vertical, the wind load is immense. Each of those pipes goes three feet into the ground and is set in concrete up to about 8 inches below the surface. And the builder added the guy system at the last minute.

But it has held up! That thing (and the roof array which I installed) survived the Derecho event a couple of years ago when my neighbor's barn across the street had its 60'x40' roof rolled up like a sardine can. When I saw that in the morning, the first thing I did was run outside and look to see if our solar array was still on the roof! :shock:

Today was the first completely clear day we have had since I installed the M215s on the roof. Here is a picture showing the energy produced by each inverter. (Please recall that the M215s are the nine inverters on the top row of the house array. All the rest of the inverters are M190s.)



I would say that the production of the M215s was entirely unremarkable on a day like today when the peak power produced by any inverters was 196W (by two M190s, one in the field and one on the garage).

Five of the M190s in the field outproduced ALL of the inverters on the roof today. (Recall they are pointed more optimally.)

I finally managed to get 12 of the M190s off the roof and down into the field array and all the new M215s installed in their places! I also "fixed" the old PV panel in the field which was not producing previously.

Now witness the power of this FULLY ARMED AND OPERATIONAL photovoltaic station!



Earlier in the day, the power had peaked just above 10 kW for the first time ever! This image was from later in the day to show all the inverters working properly and the adjustments I

Of course, this station will be completely outgunned by QueenBee's for peak power, peak daily energy production and monthly energy production. But maybe, just maybe, the difference in latitude and climate between here and there will allow me to take the award for annual energy production! :ugeek:

Regarding the comparison between the M190s and the M215s, I am finding that the M215s on the house run about 9F (5C) cooler than the M190s in the equivalent position on garage. On the hottest day I could find since the M215s went up, the M190s peaked at 131F while the M215s peaked at 122F. That's a pretty big difference, which means lower thermal cycling stress on the components in the M215s than in the M190s. That's an encouraging sign that the M215s should live a much longer life than the M190s.

RegGuheert said:

Of course, this station will be completely outgunned by QueenBee's for peak power, peak daily energy production and monthly energy production. But maybe, just maybe, the difference in latitude and climate between here and there will allow me to take the award for annual energy production! :ugeek:

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That'd be a quite the feat! Your unobstructed view of the sun certainly has mine shading beat but my higher output panels and sheer number make up for that

QueenBee said:

That'd be a quite the feat! Your unobstructed view of the sun certainly has mine shading beat but my higher output panels and sheer number make up for that

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Not so fast! It's the area FACING THE SUN that counts. Clearly you win this time of the year. But in wintertime, my system should win that contest.

I suspect the following months your system will outproduce mine:

May
June
July
August

These months I expect my system will outproduce yours:

October
November
December
January
February
March

The following months they should be about equal:

April
September

The question is how they will come out overall. That may depend upon the weather!

Here is a trivial observation of a difference between the M190s and the M215s: The M190s ALL wake up in the morning (DC Power Too Low: Clear) before ANY of the M215s wake up.

I finally got a moment where it was cool enough and/or bright enough to be able differentiate between the M190s and the M215s simply by the output power of each:



That's about all the M190s can do (199W), but I'm pretty sure from images I've seen from others' arrays that the M215s still have another 10W in them (225W).

A quick look at voltages reported by the inverters tells me that there is very little difference between a string of 7 M190s (on the top row of the garage) or the string of 12 M215s (all M215s) in terms of voltage drop. (Of course the measurement resolution is only 1V and I do not know how accurate these things are, but it's all I have to go on.) Each string indicates a voltage of 255VAC at the end of the string and 254VAC at the inverter closest to the panel. This is so even though the wiring for the M215 string is carrying 86% more current than the wiring for the M190s. The difference is that the M190 wiring is likely longer from between the two ends of the strings and is 14AWG versus 12AWG with the M215s. Also, each string is fed by a 12AWG wiring from the breaker panel, but the M190 string is about twice the round-trip distance from the panel as the M215 string. That explains why both strings are at about the same voltage at the first inverter in spite of the lower current in the M190 string.

Just for grins, I have run some calculations in the latest version of PVWatts for my old system, my new system with the additional 12 inverters and for QueenBee's current system of 73 panels. For consistency's sake, I made the DC to AC Derate Factor 0.9 for all runs.

Here are all our numbers for PVWatts with original 42 PV panels, 2011, 2012, 2013, 2014, PVWatts with 54 PV panels, and QueenBee's PVWatts predition: While I was able to get the PVWatts numbers to come out about right for the year by using the DC to AC Derate Factor of 0.9, I will note that they do not seem to match up for all months. Specifically, the predictions seem very high for October and a bit low for February and June.

Interestingly, PVWatts has my system outperforming QueenBee's in only four months: October through November, but the differences shown in those four months are enough to make up for the small number of higher months. In the end it seems clear that the weather will be the factor which determines which system produces more in a given year. Since I have been watching the two systems, QueenBee has had lots of clear days while I have seen almost none.

It is interesting to see the differences in how these systems perform!

More than a year has passed since I added the M215IGs to the system and I will say that the production numbers for the M190s and M215IGs are nearly identical, with all hovering right around 335 kWh.

I changed the title of the thread to reflect the new status of my system. In addition to the M190s and the M215IGs, I added an M190IG on September 18, 2014 which I received as a replacement for a failed M190 and I have just purchased four M250s to replace four M190s which I recently sold.

To make a better comparison for the future, I have decided I will line up an assortment of inverters under the top row of panels on the garage. Here is what I expect to end up with:

M190 - M250 - M215IG - M250 - M190IG - M250 - M250

(The last panel on the right gets shaded in the morning, so it will not help with the comparison.)

I may need to cut off one of the connectors on the Engage cable to make it work. If that happens one of the M250s will go somewhere else and there will be two M190s on the far left end.

I do not expect to see any difference between these various inverters sitting while sitting under 235Wp PV modules other than the M190s being less reliable.

RegGuheert said:

Here is what I expect to end up with:

M190 - M250 - M215IG - M250 - M190IG - M250 - M250.

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I ended up with something quite similar (on the top row of the garage array):

M190 - M215IG - M250 - M190IG - M215IG - M250 - M250

FWIW, the M190 was built in 2010, the M190IG and M215IGs were built in 2014 and the M250 was built in 2015.

The two on the left are in a different string (M190-style cabling) than the five on the right (Engage cabling). Again, the M250 on the far right is shaded in the morning, so it will not be useful for comparison. The M250 just next to it may also be useless for the same reason. Also, it is possible that the M190 on the far left over-reports how much AC it produces, so its numbers should be taken with a grain of salt. (I have seen this over-reporting happen prior to failure with some of my M190s.) The other four inverters should be valid for comparisons. :?

Here is an action photograph I took of three of the four types of competitors:



(BTW, the one in the middle that is simply labeled "enphase ENERGY" is an M215IG.)

I'll report back after I have some comparative data. There is no reason to believe that the M250s will produce more electricity than the M215IGs, but I also expect that neither of them will outproduce the M190 or M190IG by any significant margin, if at all. Time will tell.

Here is a picture of the production over the period July 16, 2015, until August 2, 2015. (Only a portion of the total array is shown to improve readability.) I have annotated the inverter type found beneath each PV module for reference:



Note that the two columns on the farthest-right edge of the garage are shaded in the early morning and the module on the bottom right on the house gets some afternoon shade. As a result, those should produce a bit less electricity than all the rest, which are in full sun. Also, the inverters third and fourth from the right in the middle row of the Garage Array are malfunctioning daily with "Grid Gone" events and therefore produce slightly less electricity.

It's a bit interesting that the old M190 in the top-left corner produced about 3% more electricity than its neighbors in that row. I attribute most of that difference to the cooling effect of the westerly winds which hit it first, but it may also be simply that the old M190 inverters tend to report more production leading up to their failure. Likely both effects are involved.

Overall, as expected, there is no real difference in production between the M190, M190IG, M215IG or M250 during the heat of the summer. It will be interesting to see if any real differences are visible during the coldest periods of the year.

FWIW, at this point, the roof arrays now contain the following:

25 - M190s (Manufactured in late 2010)
12 - M215IGs (Manufactured in early 2014)
4 - M250s (Manufactured in early 2015)
1 - M190IG (Manufactured in mid 2014)

The field array contains the following:

12 - M190s (Manufactured in late 2010)

Since the field array contains 72-cell PV modules (in a climate which gets cold enough to break the new-style inverters), I will need to keep the original-style inverters out there as long as possible. If I eventually get to the point at which I have 42 new-style inverters on the roof and I experience another failure, I may be looking to swap new-style inverters for the old M190s from someone such as Weatherman that has only 60-cell modules and/or lives in a warm climate. When and if that will eventually happen I have no idea.

Since the results are interesting, I thought I would post production of the inverter shootout from July 9 through today:



Interestingly the M190IG, M215IG and M250 are reporting that they produced exactly the same amount of energy over the previous 3.5 month period and if you look at the two M190s on the left end of the second row, they also reportedly produced that exact amount of energy.

As for the M190 in the upper left, I suspect its high production is the signature of a future failure. (The second inverter which failed in this array was reporting the highest production in the array just prior to its failure, but the replacement reports normal production.)

It will be interesting to see what winter brings.

Hi RegGuheert,

Perhaps you can educate me about this:

Since the field array contains 72-cell PV modules (in a climate which gets cold enough to break the new-style inverters), I will need to keep the original-style inverters out there as long as possible.

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I have 31 Sharp 235W mono panels as well as some 375 SW. Twenty-four of the Sharps are connected to the M190s. As you know, two of my four replacements have been the M190IG(s). I have been considering replacing all of the M190s with the new S230(s) when they are out at some point. I installed my systems and as the years go by I will reach a point where I can't keep swapping out inverters. I ran into that last year while I was blind.

Anyway, your statement gives me some concerns about that plan -- if I understand you correctly...

Thanks,
Ken Clifton