Help me understand my system

[FIDIRO]

Hello everyone, I am fairly new to solar and am trying to find out how everything is supposed to look like after nearly a year since interconnection. I have an 8.5kw Sunpower system which consists of 26 panels that are rated for 327watts that are all south roof mounted. I chose to own over lease. System is tied to the grid.

What kind of kw daily highs should I be seeing on a good day with a system this size?

I don't have access to individual panels data (they have been saying it's in the works) and I have seen my meter go forward with just the electric dryer on a sunny mid day and started to think the system is underperforning, dryer is about 5k watts when element is heating + a few low wattage things. The live data that I have access to shows at best 7.3kwh for all 26 panels and that is on a bright sunny day around noon, is this what I have to expect at this time of the year for this size system.

Sorry for the rant for a first post, just trying to better understand my system and what I can do to make it better.

Thank you all for any advice you have to offer.

[FIDIRO]

Just realized I posted in the wrong forum. If at all possible can a moderator move this to an appropriate forum. Sorry and thank you

[Ampster]

If Sunpower did not give you a production estimate you can go to PV Watts and input your system and location and get a good estimate. That might be able to tell you how many hours that you might be able to expect your system to provide 5kW. We are at the Equinox so production is down from the June Solstice.
I have a 7.9 kW system and I see only a few hours at or above 5kW at this time of year.

[J.P.M.]

Since you're asking for advice:

Before you do the PVWatts thing as Ampster suggests (which, FWIW, I think is good advice), read a copy of "Solar Power Your Home for Dummies".
A slightly out of date but still useful version of the basics is a free online PDF if you root around on the net a bit. An updated version is ~ $25 at bookstores/Amazon.
Without some education you'll probably get the PVWatts input wrong and that'll likely lead you astray.

Without more info from you about location (latitude/longitude) and array orientation, it would be misleading for folks around here to guess what your output might be if all is running nominally. The Dummies book will explain why.

BTW, you don't need individual panel data to answer the questions you're asking - just hourly or shorter time period array totals.

A well performing, shade free system with a mostly equator facing orientation on a warm day in the mid latitudes might be expected to produce something like 80 - 85 % of the array's STC rating.

If you've seen 7.3 kW power being produced by your 8.5 kW system, that's 7.3/8.5 = 0.86. So, on the face of it, it looks like your system is doing about what it might be expected to do.

Read the book for more information. If/when you do the PVWatts thing, after the book but before you attempt any inputs to the model, read ALL the help screens a couple of times, get the inputs as close to reality as possible and use a 10 % system loss parameter. And remember, PVWatts is a model for preliminary desighn. It is not a predictor of performance, especially over short periods of time.

Welcome to the neighborhood.

BTW: congrads on not getting sucked into the leasing trap.

[FIDIRO]

Thank you for the replies. I should add that I have recorded this system to produce 8.5kw on live data throughout end of last year and had my central a/c with electric dryer running and still watched the meter trinkle back, both combined are about 8500 watts running. I had also seen several times throughout this past first quarter of the year where it was live producing 8.5kw on nice sunny days but rarely compared to end of last year, so I have never been able to run both ac and dryer all summer without using grid power. Soon as summer started and I needed the max output of this system, the best I was getting was 7.3 on bright sunny cloudless days.


So now I'm wondering how it has gone down from 8.5 to 7.3 all summer. Are the microinverters capable of being remotely turned down? Panels are rated for 327 watts but I was told that they can be capable of beyond that but mine seem to have been operating at about 270 watts all summer.

I don't know how every utility Co adjusts the solar production but when I signed up for this I was told I would get a system that would produce 118% of my electric and it would work by storing the extra electricity into the grid and I would then be using it during low production days/nights. Well months after pto(10/10/2020) I continued and keep getting the normal electric utility bills and find out the hard way that I now had to pay the regular rates for anything that rolls forward which is more than double the price compared to whatever rolls back so it keeps adding up if I use power when panels can't keep up or just not producing.

Sorry again for the rant but just venting about how this system couldn't keep up in the summer when I needed it most. May have to see if I can fit in a few more panels to get the wattage I need to run the summer units.

[DanS26]

OP...to answer your concerns and questions you need more data. Specifically you need to know all your electrical inputs and outputs on a minute to minute, hour to hour and day to day basis.

How do you do that? By installing an energy monitoring system. Don't guess or suppose...get the facts. There are many systems out there to help you....Google is your friend.

[J.P.M.]

Thank you for the replies. I should add that I have recorded this system to produce 8.5kw on live data throughout end of last year and had my central a/c with electric dryer running and still watched the meter trinkle back, both combined are about 8500 watts running. I had also seen several times throughout this past first quarter of the year where it was live producing 8.5kw on nice sunny days but rarely compared to end of last year, so I have never been able to run both ac and dryer all summer without using grid power. Soon as summer started and I needed the max output of this system, the best I was getting was 7.3 on bright sunny cloudless days.


So now I'm wondering how it has gone down from 8.5 to 7.3 all summer. Are the microinverters capable of being remotely turned down? Panels are rated for 327 watts but I was told that they can be capable of beyond that but mine seem to have been operating at about 270 watts all summer.

I don't know how every utility Co adjusts the solar production but when I signed up for this I was told I would get a system that would produce 118% of my electric and it would work by storing the extra electricity into the grid and I would then be using it during low production days/nights. Well months after pto(10/10/2020) I continued and keep getting the normal electric utility bills and find out the hard way that I now had to pay the regular rates for anything that rolls forward which is more than double the price compared to whatever rolls back so it keeps adding up if I use power when panels can't keep up or just not producing.

Sorry again for the rant but just venting about how this system couldn't keep up in the summer when I needed it most. May have to see if I can fit in a few more panels to get the wattage I need to run the summer units.

Read the book. Doing so will allow you to understand how what you own works and why on some days, weeks, months or other time periods your system production will be more or less than your use. Your system may have been over sized by 18 % but that's based on numbers that change over time - your usage will change, but maybe not by as much as the weather and available sunshine, both day to day and seasonal. Seasonal production alone will vary by maybe 30 % or so from summer to winter because the sun's location is less favorable to production.

Read the book, get informed and learn about your utility's net metering program before you get any monitoring equipment.

You need to educate yourself more than you need to throw instrumentation at your ignorance without understanding what you're looking for or what the instrumentation may be giving you. You need to learn where you are and crawl a bit before you run.

FWIW, based on the little information you've been able to provide (and that looks to be based on your ignorance of what you bought and how the whole solar generation process works), it sounds (reads) to me like your system is functioning about as it was designed.

[RichardCullip]

Hello everyone, I am fairly new to solar and am trying to find out how everything is supposed to look like after nearly a year since interconnection. I have an 8.5kw Sunpower system which consists of 26 panels that are rated for 327watts that are all south roof mounted. I chose to own over lease. System is tied to the grid.

What kind of kw daily highs should I be seeing on a good day with a system this size?

It's hard to answer your question without more detail. What size inverter do you have? What part of the world do you live in? What is the panel orientation and tilt?

With this information PVWatts could be used to give an estimate of expected performance

[FIDIRO]

Central NJ

26 - 327 watt panels with micro inverters (1 inverter per panel) all panels south roof mounted.

Orientation 172

Tilt 24

Haven't had time to check out the pvwatts site but I'll try tonight.

I'm trying to find that pdf for the Solar Power Your Home for Dummies but looks like I'll just order a copy to read.

[Mike90250]

> 327 watt panels with micro inverters (1 inverter per panel)

Do you have access to panel level monitoring, to see if any micro inverters have gone bad ?

Warm weather reduces PV panel output, sometimes by 10% or even more

[SunEagle]

> 327 watt panels with micro inverters (1 inverter per panel)

Do you have access to panel level monitoring, to see if any micro inverters have gone bad ?

Warm weather reduces PV panel output, sometimes by 10% or even more

What is the model number of the micro? Depending on what it is will help identifying how many watts it will pass. That value might be less then the 327watts the panel is rated for.

[J.P.M.]

Central NJ

26 - 327 watt panels with micro inverters (1 inverter per panel) all panels south roof mounted.

Orientation 172

Tilt 24

Haven't had time to check out the pvwatts site but I'll try tonight.

I'm trying to find that pdf for the Solar Power Your Home for Dummies but looks like I'll just order a copy to read.

ZIP code ?

micro inverter max. output ?

[PVAndy]

ZIP code ?

micro inverter max. output ?

Sounds like SunPower AC Panels. Depending on age could be SolarBridge 250W AC or Enphase IQ7 SunPower version

[FIDIRO]

This is a sunpower equinox system with E20 Series 327 watt solar panels. System was installed summer 2020 zip code 08882 and don't have any info on which inverters, I would have to give them a call to try and get that information or climb up to the 2nd story roof to try and peek under panel. I'm going to say it is enphase but would need to confirm.

If I have seen 8.5kw then the inverters will likely be capable of running the panels at 327 if they are all working properly, but being that during the summer heat I was only seeing 7.3 on bright sunny days then either some panels are not producing or they drop that much because of heat.

If the summer heat did cause the drop then I should be seeing 8.5kw on good sunny days now that the heat has settled down. I don't have access to individual panel and hoping that is something that will come soon.

[SunEagle]

This is a sunpower equinox system with E20 Series 327 watt solar panels. System was installed summer 2020 zip code 08882 and don't have any info on which inverters, I would have to give them a call to try and get that information or climb up to the 2nd story roof to try and peek under panel. I'm going to say it is enphase but would need to confirm.

If I have seen 8.5kw then the inverters will likely be capable of running the panels at 327 if they are all working properly, but being that during the summer heat I was only seeing 7.3 on bright sunny days then either some panels are not producing or they drop that much because of heat.

If the summer heat did cause the drop then I should be seeing 8.5kw on good sunny days now that the heat has settled down. I don't have access to individual panel and hoping that is something that will come soon.

More than likely the micro inverters are allowing less then the 327watts for each panel so it is very unlikely that you will see that 8.5kw.