16kw system only produces maximum of 11 -12kw (phoenix, AZ)

[Squeezit]

Hello,
I live in a state where its always sunny and purchased the 16.32kw solar system with 2 powerwalls.
Previously I was generating about 13.6kw when the sun was directly above me.

It was explained that the reason I don't generate 16.32kw is because the system protects itself? (I didn't understand this part).

Anyways, one of my 2 solaredge inverters broke.

It took forever but after it got fixed, I never hit 13.6kw again.
To put it in perspective, August should have been one of my best generating months. In May I generated 3.47 MWH, in August I generated 2.87MWH (In June and July my system was broken so I'm not including that).
I seem to be even less in September, but the month isn't over so its hard to say.
But even when I check on bright sunny days at 12pm, I'm still only generating around 11.5 or so kwh.
Yesterday was bright and Sunny, no clouds like today. My max was 11.6kwh.

I have contacted support about this 3 times now in the past 2 months, but have never received a response from them.

Can anyone else help me understand if this is normal or if I'm underproducing?

One of my inverters has a green solid light, the other has a blue and green solid lights.

 

[h2ofun]

Hello,
I live in a state where its always sunny and purchased the 16.32kw solar system with 2 powerwalls.
Previously I was generating about 13.6kw when the sun was directly above me.

It was explained that the reason I don't generate 16.32kw is because the system protects itself? (I didn't understand this part).

Anyways, one of my 2 solaredge inverters broke.

It took forever but after it got fixed, I never hit 13.6kw again.
To put it in perspective, August should have been one of my best generating months. In May I generated 3.47 MWH, in August I generated 2.87MWH (In June and July my system was broken so I'm not including that).
I seem to be even less in September, but the month isn't over so its hard to say.
But even when I check on bright sunny days at 12pm, I'm still only generating around 11.5 or so kwh.
Yesterday was bright and Sunny, no clouds like today. My max was 11.6kwh.

I have contacted support about this 3 times now in the past 2 months, but have never received a response from them.

Can anyone else help me understand if this is normal or if I'm underproducing?

One of my inverters has a green solid light, the other has a blue and green solid lights.

One NEVER hits the panel ratings!!!!! I have like about 15kw of panels on a SE 11.4kw inverter, and once I clipped for a few seconds at 11.4.

 

[Squeezit]

Yeah, I get that I'll never hit 16. But being stuck at 11.6kw is my highest generation when I have a 16kw system seems super low.

According to my contract, my estimated annual production is 26,248 kWh
According to the tesla app, I'm generating about 700 kWh / month.
So unless I'm not understanding something right, I'm not just a little under their estimate like I expected, I'm severely under (by about 1,487 kWh).

It's entirely possible I just don't understand, and the tesla rep is telling me that I'm over producing But I don't really understand how that's possible

 

[h2ofun]

Yeah, I get that I'll never hit 16. But being stuck at 11.6kw is my highest generation when I have a 16kw system seems super low.

According to my contract, my estimated annual production is 26,248 kWh
According to the tesla app, I'm generating about 700 kWh / month.
So unless I'm not understanding something right, I'm not just a little under their estimate like I expected, I'm severely under (by about 1,487 kWh).

It's entirely possible I just don't understand, and the tesla rep is telling me that I'm over producing But I don't really understand how that's possible

Whats the inverter setup? One can never get more than the inverter output spec

 

[h2ofun]

Yeah, I get that I'll never hit 16. But being stuck at 11.6kw is my highest generation when I have a 16kw system seems super low.

According to my contract, my estimated annual production is 26,248 kWh
According to the tesla app, I'm generating about 700 kWh / month.
So unless I'm not understanding something right, I'm not just a little under their estimate like I expected, I'm severely under (by about 1,487 kWh).

It's entirely possible I just don't understand, and the tesla rep is telling me that I'm over producing But I don't really understand how that's possible

And nope, depending on panel placement, temps, time of year, inverter outputs, etc, seems could be fine. In winter my 15KW system at time only produce 5kwh for the entire day.

 

[Squeezit]

Sorry, I'm not sure but does this answer your question? I know I have 2 different sized converters. One is supposed to generate less than the other. The one that generates more is the one that was replaced after it stopped working for 2 months.

 

[jjrandorin]

Hello,
I live in a state where its always sunny and purchased the 16.32kw solar system with 2 powerwalls.
Previously I was generating about 13.6kw when the sun was directly above me.

It was explained that the reason I don't generate 16.32kw is because the system protects itself? (I didn't understand this part).

Anyways, one of my 2 solaredge inverters broke.

It took forever but after it got fixed, I never hit 13.6kw again.
To put it in perspective, August should have been one of my best generating months. In May I generated 3.47 MWH, in August I generated 2.87MWH (In June and July my system was broken so I'm not including that).
I seem to be even less in September, but the month isn't over so its hard to say.
But even when I check on bright sunny days at 12pm, I'm still only generating around 11.5 or so kwh.
Yesterday was bright and Sunny, no clouds like today. My max was 11.6kwh.

I have contacted support about this 3 times now in the past 2 months, but have never received a response from them.

Can anyone else help me understand if this is normal or if I'm underproducing?

One of my inverters has a green solid light, the other has a blue and green solid lights.

Why do you feel august should have been your best month? Summer solstace is in July (longest day of the year), and from that point all production will decrease.

In my case, May and june are my best months. You will be generating less every day (on average) from now until around march, and you will never hit 16.X on your 16.X system, unless you bought a ground mounted system that is situated all south, at the perfect angle for sun tracking (which I am assuming you didnt).

TL ; DR ... Its almost assuredly normal, but you can check a site like pvwatts to see what it predicts. Basing your production now off what happened in may isnt correct. August is not the best month for solar (while july is the longest days, its also hotter and heat reduces output).

 

[Squeezit]

I meant best month for me. My system was down June and July so I missed out on my "best month". But beween May and August, I feel that August should have been better. Maybe I'm wrong, I just thought the days were longer in August.

Thanks for the assistance by the way.

My app was saying 700 kWh for August, but I was informed by the rep that it was actually 2400 kWh.
I'm not sure what she did but afterwards my app updated and displayed the same thing she said.

 

[Zinc_Saucier]

Sorry, I'm not sure but does this answer your question? I know I have 2 different sized converters. One is supposed to generate less than the other. The one that generates more is the one that was replaced after it stopped working for 2 months.

View attachment 710662

Do you know which of the models in that spec sheet you have? Also, can you share a picture of your production chart? It would be relatively easy to see if you were constantly clipping due to inverter capacity.

However, as others have said, likely it’s a factor of the heat that’s causing lower production. I’m in MA and was maxing out my 10kW AC capacity in May, but with the increased temperature in July/August here (which is nothing to AZ) I’m seeing mid 8s as my peaks.

 

[jjrandorin]

This is a fairly common misconception (that a, for example 16.X sized system will produce peak power of 16.X). Here is a recent thread from a few days ago with the same question. The numbers themselves are smaller (7.1 sized system only produces 4.X) but its the exact same question just different numbers.

Read through that as a couple people give general explanations for why.

7.1kw system produce 4kw per hour

I got new Tesla 7.1kw system installed two weeks ago. 21 panels (340w) with one powerwall 2 plus I have not got pto But Tesla advisor told me I can turn on the system since I pass inspection. Here is my question I only got around 4kw at 12am to 1pm. Rest of the day is around 2kw per hour Is...

teslamotorsclub.com

 

[yblaser]

Why do you feel august should have been your best month? Summer solstace is in July (longest day of the year), and from that point all production will decrease.

In my case, May and june are my best months. You will be generating less every day (on average) from now until around march, and you will never hit 16.X on your 16.X system, unless you bought a ground mounted system that is situated all south, at the perfect angle for sun tracking (which I am assuming you didnt).

TL ; DR ... Its almost assuredly normal, but you can check a site like pvwatts to see what it predicts. Basing your production now off what happened in may isnt correct. August is not the best month for solar (while july is the longest days, its also hotter and heat reduces output).

Summer solstice is June 20th or 21st but I otherwise agree. You also need to consider temperature as generally July and August can be hotter depending on location which will also negatively impact generation.

 

[jjrandorin]

Summer solstice is June 20th or 21st but I otherwise agree. You also need to consider temperature as generally July and August can be hotter depending on location which will also negatively impact generation.

Thanks, Right idea wrong month. At my own home, my peak production for the year comes late june / early july, but thats also some of my peak energy usage because of the heat. My best months when you include home usage vs PV production are March, April and May, where production climbs every day, but temps are still mild with cool evenings, so no AC use at all for me.

 

[scotsmanswan]

Think worth looking at PVWatts as suggested in linked thread but some real life observations from my SW facing 6.6kW array in Phoenix in 2021 (just north of airport):

• May is generally highest producing month (1,224 kWh); expect to produce 20%+ less in September
• Highest daily production was May 22nd (44.5 kWh)
• June 2021 production lower than expected (large number of days with smoke from various fires)
• July 2021 production lower than expected (wetter / cloudier than normal but also cooler). Lowest production day was actually July 23rd (only produced 1.4 kWh)

 

[Squeezit]

Thanks for all the help (and explanations) guys, I really appreciate it.
@jjrandorin I'll check out that thread as you suggested, thank you. (Sorry for the delays, am at work).

 

[Laketime]

My 16.32 system peaked production at 14.5 but mostly I would peak at 14.3-14.4 this past April/May. I haven't been close since. In August the highest peak I saw was 12.5ish. That's a combo of heat and house orientation. (20 degrees east facing for 33 panels and 15 due west). A few days ago I peaked in the low 13's. You are in AZ so heat has to have a major impact plus time of year and panel orientation.

 

[CrazyRabbit]

i have 56x 320 watt = 17.92Kw and am producing about 2.4 Mwh per month or 90 Kwh per day. PVwatts says i should get 28 Mwh per year. i've had two issues since PTO, one string went down due to failed electrical connection and second was direct lightning hit. but am still producing 2.4 Mwh which is a benifit of micro inverters (iq7+).

 

[Flick75]

i have 56x 320 watt = 17.92Kw and am producing about 2.4 Mwh per month or 90 Kwh per day. PVwatts says i should get 28 Mwh per year. i've had two issues since PTO, one string went down due to failed electrical connection and second was direct lightning hit. but am still producing 2.4 Mwh which is a benifit of micro inverters (iq7+).

What's your point? Boasting about the size of your system and it's capabilities has nothing to do with what the OP was asking about.

 

[Flick75]

My 16.32 system peaked production at 14.5 but mostly I would peak at 14.3-14.4 this past April/May. I haven't been close since. In August the highest peak I saw was 12.5ish. That's a combo of heat and house orientation. (20 degrees east facing for 33 panels and 15 due west). A few days ago I peaked in the low 13's. You are in AZ so heat has to have a major impact plus time of year and panel orientation.

I definitely agree that heat could be a factor for the OP's panels and that could possibly causing the dip in performance. I'm not sure if it would be that much based on the size of the OP's system. The OP must be running a 7.6kW and 6kW SE inverter to get his initial 13.6kW.

 

[h2ofun]

I definitely agree that heat could be a factor for the OP's panels and that could possibly causing the dip in performance. I'm not sure if it would be that much based on the size of the OP's system. The OP must be running a 7.6kW and 6kW SE inverter to get his initial 13.6kW.

If those are the inverter sizes, thats all he will get, no matter how many panels he has connected, in BEST case.

 

[Flick75]

If those are the inverter sizes, thats all he will get, no matter how many panels he has connected, in BEST case.

Agreed. The inverter clipping will only give him 13.6kW, but why is he only getting 11.6kW now? Even with a 5% loss of efficiency due to heat, that still doesn't add up to the extra 2kW he's still loosing.