Need to decide on a system design 6.3 kW - San Marcos

[gvl]

Solar Edge is 2 strings only, it may not apply in this case but depending on how they are oriented it is possible it may have difficulties optimizing 4 planes I would think.

Are ABB 300W micros any good?

[thejq]

thejg - Just so I am clear on the clipping, I took a look at your output. On a sunny day earlier this week, it looks like your panels got up to 282 watts at the best part of the day. So with the m250, anything over 250 would just produce and show 250? Then in summer they likely will be producing even more so I would see a loss due to the inverters ability to handle it. I will have a good portion of my panels S or SW so I should have similar production with 300s as you since we live pretty close.

Thanks,

Brad

Yes, with m250 anything above 250W will be clipped. And yes, if your S and SW facing panels has around 20 degree tilt, you will see similar results as mine. Just a few days ago I saw this at peak, so it's almost getting maxed out, although just momentarily.
Capture.JPG

[hockeydude]

Help understanding Clipping

If you have decent orientation (W or SW), you will definitely get clipped with m250 + LG300. Since we are about 10 miles away, you can look at my outputs in a sunny day, and estimate how much clip you will experience. Note, according to pvwatt, my best production month is July which is still 2 months away. Also when it clips, the inverter is running at max rated capacity for an extended period of time. Common logic says it mustn't be good for longevity. If you're going with LG280, maybe m250 is ok, but I wouldn't do it with LG300/305, especially with a saving of just $0.05/W.

As for the conduit, if the only reason is aesthetics, as long as the wife approves (as well as HOA), I'd save that $2K. You can have the installer paint it to match your exterior color to lessen the impact. In a few months, you will probably not going to notice it.

thejg - Just so I am clear on the clipping, I took a look at your output. On a sunny day earlier this week, it looks like your panels got up to 282 watts at the best part of the day. So with the m250, anything over 250 would just produce and show 250? Then in summer they likely will be producing even more so I would see a loss due to the inverters ability to handle it. I will have a good portion of my panels S or SW so I should have similar production with 300s as you since we live pretty close.

Thanks,

Brad

[thejq]

If you have decent orientation (S or SW), you will definitely get clipped with m250 + LG300. Since we are about 10 miles away, you can look at my outputs in a sunny day, and estimate how much clip you will experience. Note, according to pvwatt, my best production month is July which is still 2 months away. Also when it clips, the inverter is running at max rated capacity for an extended period of time. Common logic says it mustn't be good for longevity. If you're going with LG280, maybe m250 is ok, but I wouldn't do it with LG300/305, especially with a saving of just $0.05/W.

As for the conduit, if the only reason is aesthetics, as long as the wife approves (as well as HOA), I'd save that $2K. You can have the installer paint it to match your exterior color to lessen the impact. In a few months, you will probably not going to notice it.

[sensij]

How did quote 2 plan to run the conduit?

[hockeydude]

So I have met with several vendors now and trying to make sense of everything. I have read quite a few post on this site but still don't have a feel for what would be best. I have a difficult roof because there is no one big surface to put it so it will need to be split between 3 or 4 sections. Three areas are pretty good and one would not be bad just not as good as the others. I have been told because of the layout of my roof, the install costs are going to be higher than someone with the ability to put all their panels in one array.

Currently:
Average Use: 913 kWh/month, 10,953 kWh/year
Have Led/CFL in most of house

The quotes below are for cash price:

Quote 1
I won't even post because it is so high.

Quote 2
6.3 kW
21 LG300N1C Panels
21 Enphase M250-60-240-S22 MicroIntverters
Envoy/Enlighten monitoring
Vendor estimate production: 10,690 kWh (I don't get this high number when I use PVWatts with default loss settings)
Cost: $22,635
$3.55/watt DC (before tax credit)

Quote 3 - Option 1
Vendor thinks there is only optimal prime roof space for 18 panels
5.49 kW
18 LG305NIC-B3 Panels
Solar Edge Se5000 Inverter / 18 Solar Edge P320 Power Optimizers
Solar Edge Monitoring
Vendor estimated production: 8,311 kWh
Cost: $22,532
$4.10/watt DC (before tax credit)

Quote 3 - Option 2
Vendor provided me a quote upon me asking for similar system as Quote 2 with 21 panels for comparison purposes
6.3 kW
21 LG300N1C Panels
Solar Edge SE6000 Inverter / 21 Solar Edge P320 Power Optimizers
Cost: $24,825
$3.94/watt DC (before tax credit)

Interestingly enough, this vendor said if they run the conduit on the outside along the roof the cost would go down over $2,000 and he said it is because the roof work is minimized not having to bring the four arrays into the attic. That is a lot of money just for aesthetics unless there is another reason to have them in the attic. It's a two story house so not that visible from the street anyway. Then the price would be closer to the $3.60/watt.

So of course the biggest question is how many panels I can fit that will work well. I guess I will have to have one of them do their final measurements to find out for sure. The it comes down to system design, the Solar Edge Inverter with Power Optimizers or the Enphase Microinverters. I asked about having the 305 panels with the miroinverters but he said there could be clipping but that may even be the case with the the 300 panels right?

The quotes are from vendor recommendations from others on this forum. So I am close to the $3.50 price target I was shooting for but my roof layout seems to be adding a bit more cost than those that can fit is all in one or two arrays.

Sorry for all the questions I have within this post but any help/suggestions are appreciated. Thanks.