8.1 kW system daily production?

[Shopaholic]

Hi all,
My 8.1 panels system is up and running since May but I never saw more than 7 kW at peak and mostly 6.7-6.5 or so on a bright sunny day, not counting cloudy days or smoke (average daily total 45- 52 kWh). Is this an acceptable number or not. I placed a service request and Tesla claims that it’s working fine. Thanks

 

[Zinc_Saucier]

Try plugging in your system info into a calculator like PVWatts to see what’s expected. Are all your panels oriented the same? If you have arrays facing different directions you may not hit the inverter limit. Also is the 8.1 your DC system size or the AC inverter size?

 

[tstolze]

So much can impact production, location, panel facing direction, panel angle, temperature, smoke/haze.
With that said, sounds about right to me, our 7.65 system that faces west near St. Louis, MO rarely produces over 50 kWh's in a day (only 7 days in 9 years)
Our peak of 6.75 is seen, but kind of rare other than when the Sun just clears from clouds, takes a cool day at the right time of the year.

 

[jjrandorin]

Hi all,
My 8.1 panels system is up and running since May but I never saw more than 7 kW at peak and mostly 6.7-6.5 or so on a bright sunny day, not counting cloudy days or smoke (average daily total 45- 52 kWh). Is this an acceptable number or not. I placed a service request and Tesla claims that it’s working fine. Thanks

The system size doesnt correlate exactly to max production numbers. A lot of people seem to think that "my system size is 8.1 so I should see that number as max production" but most of the time, that isnt the case due to angle of panels, etc.

My 8.7 kW system size never generates more than 6.4 at any one point.

TL : DL, without a lot more info, its "probably" fine.

 

[bryan995]

Our 8kW is doing about 48-53 kW per day.
8 panels south
8 panels west
8 panels east

 

[SadSolar]

hmm. FWIW, Shopaholic, here's my system for your comparison
Quantity: 24 Panels
System Size: 8.16 kW
Est. Annual Production: 12641 kWh

Averaging 38kWh this whole summer...

 

[Bitslizer]

hmm. FWIW, Shopaholic, here's my system for your comparison
Quantity: 24 Panels
System Size: 8.16 kW
Est. Annual Production: 12641 kWh

Averaging 38kWh this whole summer...

View attachment 693678

What inverters do you have... Looks like it's clipping at 6.2? That's just a little lost though nearly peak when it seem to be clipping

 

[jboy210]

What inverters do you have... Looks like it's clipping at 6.2? That's just a little lost though nearly peak when it seem to be clipping

What looks like clipping to you? My curve decreases the rate of increase at its peak . I always thought that was normal.

 

[MCNE]

Hi all,
My 8.1 panels system is up and running since May but I never saw more than 7 kW at peak and mostly 6.7-6.5 or so on a bright sunny day, not counting cloudy days or smoke (average daily total 45- 52 kWh). Is this an acceptable number or not. I placed a service request and Tesla claims that it’s working fine. Thanks

Hello, that actually looks pretty good based on the system size you stated. I know there are tools others utilize to estimate the output that might be helpful. This is extremely close to folks I know with non Tesla based systems around 8-8.4kw.

My 11.2kw system will hit north of 10 on a clear somewhat cool day. Summer however is down to north of 9 with outside temp at 95+. Hopefully this helps a little.

 

[Shopaholic]

All my panels are facing south west (240 d). They put solar edge HD wave inverter. Thanks for all replies, made me less anxious

 

[Bitslizer]

What looks like clipping to you? My curve decreases the rate of increase at its peak . I always thought that was normal.

The curves seen to have a flat top, consistent flat top peak usually mean clipping

 

[charlesj]

The system size doesnt correlate exactly to max production numbers. A lot of people seem to think that "my system size is 8.1 so I should see that number as max production" but most of the time, that isnt the case due to angle of panels, etc.

My 8.7 kW system size never generates more than 6.4 at any one point.

TL : DL, without a lot more info, its "probably" fine.

One thing to add is that the inverter size is the peak limiter of production. What I see mostly posted is the DC rating of a system. And, panels are rated in a lab with flash rating, really unrealistic in real world production.

 

[charlesj]

All my panels are facing south west (240 d). They put solar edge HD wave inverter. Thanks for all replies, made me less anxious

What is your inverter size?

 

[charlesj]

What looks like clipping to you? My curve decreases the rate of increase at its peak . I always thought that was normal.

Well, it is if the panels are not large enough to clip the inverter or just barely able to in which case that apparent flatness is not very wide. As the DC to AC ratio increases, the longer it will be essentially flat, not ruler flat though

 

[charlesj]

hmm. FWIW, Shopaholic, here's my system for your comparison
Quantity: 24 Panels
System Size: 8.16 kW
Est. Annual Production: 12641 kWh

Averaging 38kWh this whole summer.

What size is the inverter? Could you check the peak for that Aug 7 production? Unfortunately you need to backtrack by the day. Curious if it is the max for your inverter

 

[SadSolar]

What inverters do you have... Looks like it's clipping at 6.2? That's just a little lost though nearly peak when it seem to be clipping

I have a Delta M8... I think it's supposed to support up to 9.6kW DC voltage?

 

[Bitslizer]

I have a Delta M8... I think it's supposed to support up to 9.6kW DC voltage?

M8 is 7.6, m10 is 9.6

Get the Delta m professional app so you can see the string voltage and amp. Get a screen shot at the peak then we can better tell what's going on

 

[JCLJorgenson]

Those numbers seem reasonable to me. I'm in San Diego with an 8.16kW system with a Tesla inverter, estimated to produce 12,921kWh a year. I have 10 panels facing SE and 14 facing SW. My summer production (on clear days) typically falls between 45 kWh and 51 kWh and I have never seen peak production exceed 6.8 kW (it typically falls between 6.5 kW and 6.7 kW).

Keep in mind that most homes have panels on different roof planes, so peak production on one plane (from the sun angle) may not align with the other plane's peak production time. As an example, if all of my 24 panels were on one plane, I would expect a higher peak production amount in the middle of the day, but a steeper bell curve when looking at solar generation. In other words, with my SE and SW layout, I get better production earlier and later in the day, but my bell curve should be a little more flat in the middle of the day (also showing a lower peak production rate). I prefer to have the SW panels because it generates more energy back to the grid during peak rates for NEM (after 4 pm for summers).

For the reason mentioned above, I would suggest you focus on total daily production and compare to the PV Watts calculator. For my home, PV Watts is calculating my June, July and August production to be about 1,300 kWh a month and my actual generation was 1,362 kWh in June and 1,366 in July.

 

[h2ofun]

Those numbers seem reasonable to me. I'm in San Diego with an 8.16kW system with a Tesla inverter, estimated to produce 12,921kWh a year. I have 10 panels facing SE and 14 facing SW. My summer production (on clear days) typically falls between 45 kWh and 51 kWh and I have never seen peak production exceed 6.8 kW (it typically falls between 6.5 kW and 6.7 kW).

Keep in mind that most homes have panels on different roof planes, so peak production on one plane (from the sun angle) may not align with the other plane's peak production time. As an example, if all of my 24 panels were on one plane, I would expect a higher peak production amount in the middle of the day, but a steeper bell curve when looking at solar generation. In other words, with my SE and SW layout, I get better production earlier and later in the day, but my bell curve should be a little more flat in the middle of the day (also showing a lower peak production rate). I prefer to have the SW panels because it generates more energy back to the grid during peak rates for NEM (after 4 pm for summers).

For the reason mentioned above, I would suggest you focus on total daily production and compare to the PV Watts calculator. For my home, PV Watts is calculating my June, July and August production to be about 1,300 kWh a month and my actual generation was 1,362 kWh in June and 1,366 in July.

what is your inverter size?

 

[charlesj]

I have a Delta M8... I think it's supposed to support up to 9.6kW DC voltage?

That is a DC to AC ratio of 1.2, not very high at all. Doubt it will clip much at all.