Solar and power wall 3 quote.

[EbS-P]

Must be the difference between having a battery and not having one. I wasn't solar powered until the power company installed the meter and gave the okay to flip the switch - which took nearly all the 20 working days they are allowed (okay, a couple of days were also for the town inspector). Naturally, that November was bright, sunny and dry - right up until the day after the meter was installed.

We all got new smart meter 3 years ago. Once they completed the reconnect order after they passed inspection ( panel upgrade was needed to install backup switch) the system was 100% functioning. Once final the final electrical inspection was completed and was uploaded to Duke I was given permission to export.

Working with my installers they handled all the paperwork with Duke. I had a few documents to sign electronically.

 

[begreen]

We had an inspection but had to wait for the power company put in a second meter for grid-tie monitoring 10 yrs ago.

 

[EbS-P]

We had an inspection but had to wait for the power company put in a second meter for grid-tie monitoring 10 yrs ago.

I was not envisioning a system like power wall 3 ten years ago! I wonder what will being installed in 2035? My guess is not much residential solar.

 

[begreen]

We'll see. By then maybe we will have very affordable perovskite panels achieving >25% efficiency?

 

[EbS-P]

Sunny day today 37 kWh production.

 

[stoveliker]

Holy moly. How many kW do you have again?
My 7.2 kW system lifetime max day production is 37 kWh. But not in September...

 

[EbS-P]

Holy moly. How many kW do you have again?
My 7.2 kW system lifetime max day production is 37 kWh. But not in September...

10.5kw

And I get shady at about 4pm now. That will only get worse as we move into winter.

 

[stoveliker]

I think you'll have 55 kWh days in summer

 

[EbS-P]

I think you'll have 55 kWh days in summer

I use 60kwh on hot days and 80 if I charge the car. Last year my average September usage was 35 kWh per day. I think if I don’t charge the car at home much we sized to cover 90% of our annual usage. Dukes credits cap at 10 kw. And won’t allow installs that sized larger than your past 12 months usage. Today wasn’t perfect but I doubt I get much more than that in September.

 

[bogieb]

Holy moly. How many kW do you have again?
My 7.2 kW system lifetime max day production is 37 kWh. But not in September...

I have an 8.0 kw system and my best day was 49.7kwh June 15th of this year (I had a 49.3 day June 2023). September, forget about it. My best producing day last September was 30.3. and it looks like September 3rd of this year I got 30.6.

To indicate the vagaries of the weather spring-fall, My best producing month of 2023 was in May, at 1.1 Mwh. This May I was at 914 kwh. My best producing month in 2024 was July, with 1.1 Mwh while July 2023 was at 931. My best producing months for both years were May, June and July. Makes up for the 116 kwh that I produce in January

 

[woodgeek]

My dumb question: is the kW rating based on nominal max panel output (which I think), or maximum output including cosine losses on the summer solstice?

Different outcomes could come from roof pitch relative to latitude. Folks could post both and compute cosine loss on June 21.

 

[stoveliker]

my 7.2 kW (power!) rating is based on max output (1 sun at 90 degrees).
Production estimates (a different thing) should always involve terrestrial geometry input...

I think my low performance is due to me having a split system, with half facing East and haf facing West. AND I have hills on East and West sides, hard cutting production early and late. ANd then I have one big tree East that cuts into summer morning production before 10 AM, and multiple trees South and West that cut summer late after noon (3.30 pm) and in winter all afternoon.

 

[bogieb]

I have no idea about roof pitch, but it is a flatter hip roof; max would be 4:12. My total for last year my system was 6.8 Mwh. So, it produces way less than capability if I had ideal conditions, location and weather.

I have panels on the east, south and west sides. I have shade challenges with hill and trees on the east side. South side has some shade. West side is completely clear, but during winter gets no direct sun. My house is off orientation a bit, so my west side is a few ticks north of west (several companies wouldn't consider putting panels on the west side - I had to advocate for it and and happy I did as it rocks during summer)

I'm in NH, so my sun angle during winter sucks big time - even without the hill and shade struggles.

My dumb question: is the kW rating based on nominal max panel output (which I think), or maximum output including cosine losses on the summer solstice?

Different outcomes could come from roof pitch relative to latitude. Folks could post both and compute cosine loss on June 21.

That would work great if there were no such thing as weather. June 21, 2024 I only produced 19.4 kwh and it was not heavily overcast



The next day I only produced 8.1 kwh. I think this graph for the month of June kind of tells the story about how many actual sunny days I get. Now, if I lived on a clear ridge - I think it would look much different even with the same weather.

 

[EbS-P]

Will be good productive day today! Was making 3 kWh at 9:30 am. Costal flood warning means my battery was charged from the grid as soon as the warning was posted.



Just measured roof is at 25 degrees slope and array points at a heading of 210 degrees. Sun came out and I hit 9.1 kW just now. A few days shy of the fall equinox I’m hitting 87% rated capacity.

 

[EbS-P]

Well here is the best September day I could hope for. Not sure what the wiggles are in the AM. Might have been a could or I might get some shade from my chimney. 40 kWh. I can’t do any better than that. You can see the PM shade I figure it’s cutting off maybe 5-6 kWh.

 

[begreen]

With our lower angle of the sun now hitting tree tops, I won't see a bell curve like that until next May.

 

[EbS-P]

With our lower angle of the sun now hitting tree tops, I won't see a bell curve like that until next May.

Being at 34 degrees latitude helps. Around Summer solstice I will be cranking out some electrons! that late PM shade will have a mich bigger impact for the 60 days around winter solstice. My 12-2 should be ok

 

[begreen]

This is what we saw today. Our inverter caps out at 4.2kW.

 

[stoveliker]

A.good day September 17 Last year.
September doesn't have the tree in the East hindering in the morning (Sun already rises to the south of that tree), but the afternoon sucks.

 

[begreen]

20.3kWh generated today. Not bad considering a foggy start.

 

[bogieb]

Well here is the best September day I could hope for. Not sure what the wiggles are in the AM. Might have been a could or I might get some shade from my chimney. 40 kWh. I can’t do any better than that. You can see the PM shade I figure it’s cutting off maybe 5-6 kWh.

View attachment 329955

Can you see what each panel's output is? It was amazing what my short chimney did to 2-3 panels for production. I contacted my installer and told him I had 2 east-side panels that were under performing compared to their neighbors. I only get totals so I could not see what they did hour by hour (or at least, I haven't figured it out and I really don't care that much). The installer contacted Enphase and they ran the graph that showed when they were severely impacted - which told them it was a chimney or other structure on the house. Sure enough, when I had the chimney shortened by a couple of rows and capped (circumstances occurred where I didn't need that chimney any more) the noticeable difference in production went away.

With our lower angle of the sun now hitting tree tops, I won't see a bell curve like that until next May.

Same, although it gets a bit better once the leaves drop.

 

[EbS-P]

Can you see what each panel's output is? It was amazing what my short chimney did to 2-3 panels for production. I contacted my installer and told him I had 2 east-side panels that were under performing compared to their neighbors. I only get totals so I could not see what they did hour by hour (or at least, I haven't figured it out and I really don't care that much). The installer contacted Enphase and they ran the graph that showed when they were severely impacted - which told them it was a chimney or other structure on the house. Sure enough, when I had the chimney shortened by a couple of rows and capped (circumstances occurred where I didn't need that chimney any more) the noticeable difference in production went away.



Same, although it gets a bit better once the leaves drop.

Probably not. But I’ll ask. I think I have 3 strings. Powerwall 3 has built in inverter so micro inverters are not possible. I could probably get string production maybe from the installers portal by not mine. If it’s a tree I could possibly do something about it. Chimney is going to stay as it.

The did relocate 3 panels from the original layout. The
Original location was the first location to get pm shade. New location one is close enough to get some shade.

 

[begreen]

Same, although it gets a bit better once the leaves drop.

We're on the north slope which exaggerates the effect of the low sun angle. Most of the trees that start shading the panels are old, tall evergreens.

 

[EbS-P]

Pano shot from about the center of the array this AM

 

[stoveliker]

They didn't give you the fish eye pics they took from the corners of your roof? (That is the only way to calculate a.solid estimate of yearly production).