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

[QueenBee]

Sorry for not linking to it directly. I meant the simple model like this: http://www.quickmountpv.com/products/co ... 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

[RegGuheert]

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

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.

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.

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.

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.

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

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

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!

[QueenBee]

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.

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.

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.

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!

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

[RegGuheert]

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.

[wwhitney]

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.

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

[RegGuheert]

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.

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

[QueenBee]

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-pha ... tallation/" onclick="window.open(this.href);return false;

[RegGuheert]

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

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!).

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-pha ... tallation/" onclick="window.open(this.href);return false;

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!

[RegGuheert]

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.)

[RegGuheert]

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!

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.