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nakman

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Hey Ray ok that makes sense, and I was kinda doing that right when they hooked it up, but I'll do a more serious test again here when it's sunny again and the panels have melted. I also got a response back from Project Solar.. which makes little sense but smells like maybe something's awry after all. here's what she said:

Hey Tim,
I am going to have to get some more install pictures from the isntallers so we can look at the consumption meter. If I am unable to see what may be going on from those pictures I will have someone come by at the end of the week!
Thanks,

I'd be shocked if someone came out this week, but we'll see.
 

rover67

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Oh yeah scratch what I said I thought it was watts over time
 

DaveInDenver

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Yeah the graph is weird but it looks ok to me. I went cross-eyed counting the lines but it adds up to the KWh produced by your system from what I can tell. It looks like the graph program just makes a new bar once 1 kWh has been produced.
Interesting. What an odd way to display it. The point of charting something is so that you can tell the information at a glance. Kind of silly to have to do an analysis to understand a graph.

For cumulative I'd think this would make more sense, e.g. kW-hr accumulated in this case per day.

CUMULATIVE.jpg

Or for hourly generating something like this, e.g. instantaneous watts per hour like Marco thought.

solar-panel-output-by-time-of-day.png
 

gungriffin

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They are just 15 minute bars. There are 12 of them every 3 hours. It is just a coincidence that his system is producing about 1kWh every 15 minutes.
 

DaveInDenver

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They are just 15 minute bars. There are 12 of them every 3 hours. It is just a coincidence that his system is producing about 1kWh every 15 minutes.
Just (to me anyway) not intuitive to do kW-hr per step time. Either accumulate or drop the redundant time. It seems to be normalizing to end up with another way to display the power generating capacity at any given moment.
 

FireMike

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I'm just seeing this so I'm behind the thread. Thanks guys for all of this great info, I'm in the middle of putting my system in. I've got Blue Raven installing the system on my house without battery backup, but I will be getting the tax incentive. My cabin in the back has a 800 watt wind turbine with controller and 220 AH battery backup, and I'll be adding a few Solar panels also as the controller is setup for both, Hybrid. This setup can be used either through the ATS if utility goes down or if the main breaker is off it can back feed the cabin always. It's not up and running yet but I'm making progress slowly. My electrician buddy who is giving guidance says it should be interesting when the inspector comes for the house system, I may hide the turbine to be safe.
 

nakman

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gonna be a fun ride, Mike! As long as you expect resistance from the inspector, solar company, installer, and Xcel energy at every possible turn, the process should run smoothly and according to plan. Worst being Xcel.


And on that, I'm now questioning how well they hooked up my new meter here. I have already asked this question to Project Solar, but suspect I will be taking this up with Xcel energy directly. My electric bill for January was $110.78. And I used 697 kWh
xcel_bill.png


the usage seems in line, I have a hot tub now that I didn't have a year ago, which was on the whole time. My usage a year ago this same time period was 610kWh. So +87 kWh to power a hot tub in January, I'm good with that.

usage.jpg


My solar production in this same time period was 522 kWh.
solar_production.png



All of this seem great. Except the part where they deduct the 522 from 697? Can any of you guys show me on your Xcel bill what this looks like? I feel like I should either see that line item deduction, or the bill should only be for the difference between the two here... maybe I don't understand net metering.
 

RayRay27

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gonna be a fun ride, Mike! As long as you expect resistance from the inspector, solar company, installer, and Xcel energy at every possible turn, the process should run smoothly and according to plan. Worst being Xcel.


And on that, I'm now questioning how well they hooked up my new meter here. I have already asked this question to Project Solar, but suspect I will be taking this up with Xcel energy directly. My electric bill for January was $110.78. And I used 697 kWh
View attachment 101629

the usage seems in line, I have a hot tub now that I didn't have a year ago, which was on the whole time. My usage a year ago this same time period was 610kWh. So +87 kWh to power a hot tub in January, I'm good with that.

View attachment 101630

My solar production in this same time period was 522 kWh.
View attachment 101631


All of this seem great. Except the part where they deduct the 522 from 697? Can any of you guys show me on your Xcel bill what this looks like? I feel like I should either see that line item deduction, or the bill should only be for the difference between the two here... maybe I don't understand net metering.
That's one of the biggest problems with the home solar-Xcel relationship. I wish there was a better explanation of how much is produced compared to what is used from the grid. This can be pretty confusing. I asked Sunrun to give me a full run down of how to read my bills and even they were like I need to talk to Xcel.

Other thing is since your system was recently activated by Xcel you may not see the benefits until next month. Xcel is typically about a month behind when it comes to billing usage charts. I usually check my usage on Xcel's website using myaccount. If you go to "My Usage and Cost" this gives you the best view in my opinion of usage vs. production. Below is a full year of usage.

1643905065480.png


1643905300987.png
 

nakman

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seriously, I need to wait another month? that'll be March... I ordered this is May. I guess if that's part of the process, but just doesn't make sense to me. will see what the solar company has to say, suspect it may be the same line though, thanks Ray. :(
 

DaveInDenver

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seriously, I need to wait another month? that'll be March... I ordered this is May. I guess if that's part of the process, but just doesn't make sense to me. will see what the solar company has to say, suspect it may be the same line though, thanks Ray. :(
Did you choose to bank the energy? That would only show up at the end of the year. If you asked Xcel to do continuous rolling over then excess power would be shown as a billing credit.

But more to the point, are you sure you actually even sold energy back to Xcel? You may have simply offset your hot tub.

Quick calculation shows it takes 145,775 BTU to warm 500 gallons of water from 65°F to 100°F, which is roughly 43 kW-hr. Of course keeping it hot will depend on ambient and what-not. But when you say you ran it all the time doing that 30 times is 1,282 kW-hr so seem plausible your solar just paid for that?

Still think you should have seen a zero kW-hr customer generated line item if net metering was working, though.
 

nakman

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@DaveInDenver Dave I am pretty sure everyone is on the "end of the year plan," whether they want to or not. But that doesn't mean you pay your full bill all year then receive back a big check, that is only for any surplus production you netted over the course of the year. We talked about that briefly in this thread, posts 92, 93, etc.

As for the hot tub I don't think it's possible to consume that much power. The water was brought up to temp in November, so all it had to do was maintain it. And ask any hot tub person they'll concur the delta in the power bill is only about $20/month in the winter, 10-15 in the summer.

So I've been in an email exchange with Project Solar, who I believe is sincere when they say the problem lies with Xcel. My response from yesterday.
I am still waiting on communication back from the installers on your utility company and install photos. I have bugged them again and again. They are waiting on a response back from Xcel and waiting on the installer to send more pictures from the initial install.

I don't think it helps them that they sub out all of the installs, makes chasing down issues a lot more difficult, plus they forgo any opportunity for continuous improvement in the process. But that's the business model.. similar to the remodel construction industry.

But she must have shaken something loose, as this morning I received 4 emails from Xcel- 2 duplicates of each other, but 1 states that contragulations my net meter is installed, the other states contrats I've received my permission to operate and can now start using the sytem. So I guess this whole time I've just been pretending to have solar.. I'll chase down some credit with them once this system is actually operational, metric being the monthly power bill.
 

gungriffin

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@DaveInDenver Dave I am pretty sure everyone is on the "end of the year plan," whether they want to or not. But that doesn't mean you pay your full bill all year then receive back a big check, that is only for any surplus production you netted over the course of the year. We talked about that briefly in this thread, posts 92, 93, etc.

As for the hot tub I don't think it's possible to consume that much power. The water was brought up to temp in November, so all it had to do was maintain it. And ask any hot tub person they'll concur the delta in the power bill is only about $20/month in the winter, 10-15 in the summer.

So I've been in an email exchange with Project Solar, who I believe is sincere when they say the problem lies with Xcel. My response from yesterday.


I don't think it helps them that they sub out all of the installs, makes chasing down issues a lot more difficult, plus they forgo any opportunity for continuous improvement in the process. But that's the business model.. similar to the remodel construction industry.

But she must have shaken something loose, as this morning I received 4 emails from Xcel- 2 duplicates of each other, but 1 states that contragulations my net meter is installed, the other states contrats I've received my permission to operate and can now start using the sytem. So I guess this whole time I've just been pretending to have solar.. I'll chase down some credit with them once this system is actually operational, metric being the monthly power bill.
What a pain in the butt. I loath systems where there isn't good organization for solving the problem when something goes wrong. This frustration being the norm is about the only thing keeping me from tossing panels up on my roof.
 

nakman

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So I seemed to have stumped the expert. Got a call back from the tech support guy, who started off telling me how well my system is running... I've produced 590kWh this year, yippee. I asked why my production graphs have such a severe plateau to them. Was told they are intentially governed at 90%, to allow for sudden spikes such as a lightning strike or something. Then we figured out how to see my data in watts (or kilawatts, but I can move a decimal point), rather than kWh. I just need to mouse over one of the bars.

solar_peak.jpg

So my system peaks out at 4.1 kW, or 4100 watts. My only issue with that is I purchased 17 320 watt panels, which is 5,440 watts. scale that back 10% and I should still see 4,896 watts.. So why doesn't that graph peak out at 4.9, rather than 4.1? I'm throttled back 25% here, not 10. And as the angle of the sun improves, I'll produce no more power, just longer periods of 4.1kW. Apparently I'm the first guy to ask this question, they're going to have to call me back.
 

DaveInDenver

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So my system peaks out at 4.1 kW, or 4100 watts. My only issue with that is I purchased 17 320 watt panels, which is 5,440 watts. scale that back 10% and I should still see 4,896 watts.. So why doesn't that graph peak out at 4.9, rather than 4.1? I'm throttled back 25% here, not 10. And as the angle of the sun improves, I'll produce no more power, just longer periods of 4.1kW. Apparently I'm the first guy to ask this question, they're going to have to call me back.
You will rarely get exactly 100% from a solar panel. Their rating is based on what is known as STC, Standard Test Conditions. These are based on the temperature of the panel itself and the ambient air both being 25°C/77°F, 1,000 watt/m^2 irradiance falling upon it in an air mass (AM) of 1.5.

At this time of year Denver will get about 3.25 kWh/m^2 on a panel facing directly south at a tilt of 42°. This is over about 4.4 hours, though. So the daily insolation average is maybe about 800 watts/m^2 this time of year. It would also be lower if your panels aren't tilted at 42°, which is possible if they're fixed and your roof isn't that steep.

So getting ~75% of nameplate rating this time of years isn't bad or surprising. You'll get a lot more in June and July. Wouldn't surprise if you got more than 90%. Insolation is maybe twice as high in the summer here and would be more than 1,000 W/m^2.

In the summer what hurts you is the panel temperature gets very high. The temp coefficient is on the order of -0.30 %/°C. So if your panels go to maybe 45°C (+20°C over STC) that means even if you have ~1kW/m^2 and perfect tilt (about 70° then) the panel will still be ~6% lower than nameplate rating.
 
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nakman

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I get that it will never be 100%, but it's just so obvious that it is being limited to 75%. I can scroll back through days and days of data where my graph plateaus at that 4.1 kW mark. In fact if this continues, my next test will be to go up there and unplug 3 of my panels, I'm guessing I still hit 4.1. My panel tilt relative to the sun couldn't be better right now... 4:12 roof pitch facing dead south.
 

DaveInDenver

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I get that it will never be 100%, but it's just so obvious that it is being limited to 75%. I can scroll back through days and days of data where my graph plateaus at that 4.1 kW mark. In fact if this continues, my next test will be to go up there and unplug 3 of my panels, I'm guessing I still hit 4.1. My panel tilt relative to the sun couldn't be better right now... 4:12 roof pitch facing dead south.
Yeah, that came to mind as I thought about it more. It is obvious your inverter(s) is(are) limiting, but that's not unusual, like they say, to have significant overhead DC capacity to achieve your AC rated power under marginal conditions and as panels age.

I've mucked up you thread to the point I may not see this, but did they sell you a 4kW or 5.44 kW or something else for the system? I mean you say you purchased 17 x 320 watt panels but what is the AC capacity they actually promised?

Those Enphase inverters might just need new setpoints, if they're programmable anyway. Or maybe you're still not getting all 17 online. That should be easy to tell. Do you know the exact model of inverter? They might be undersized and just clipping.

You know, now that I think about it you might be seeing a watts vs. volt-amps (VA) problem. You're used to seeing watts, which is real power. In DC power is always watts. When you work with AC the idea of imaginary (or apparent) power has to be introduced. If your inverters are 250 VA then everything is actually working as you'd expect, you're generating 17 * 250 = 4,250 VA and can only do 4,250 watts of work.

Xcel has always taken care of this for you. You only pay them for real power, e.g. watts, since that's all that can be metered or do actually work.

However their power plants are also generating apparent power (reactive) to handle the fact that loads aren't all real. Any motor, for example, throws the relationship of voltage to current off due to inductance. This is measured in what's called the power factor and will tell you how out of phase voltage and current can get. A PF of one is when watts = VA. When PF is anything other than one they you're asking Xcel to do generating work for free. They put capacitors on the grid to correct PF, since non-resistive loads are historically inductive. Ultimately the power factor feeds into a calculation for required engine power (or DC panels in this case) necessary to drive the alternators (inverters) to maintain stability. Ultimately the total apparently power is what circulates in the grid, the reactive part just can't do anything useful but does cause real problems.

When you're tied to the grid you have to account for this so that you don't overtax your system, which could cause issues to both your system and the grid's integrity, perhaps if you suddenly fall off voltage or frequency. Maybe ask the system engineer to look into PF, explain whether the inverters are sized or set correctly and meet the promised capacity.

Maybe you actually were supposed to get 290 VA inverters (290 * 17 = 4,930 VA), for example. That would give you around 9% DC-AC margin.
 
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RayRay27

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I get that it will never be 100%, but it's just so obvious that it is being limited to 75%. I can scroll back through days and days of data where my graph plateaus at that 4.1 kW mark. In fact if this continues, my next test will be to go up there and unplug 3 of my panels, I'm guessing I still hit 4.1. My panel tilt relative to the sun couldn't be better right now... 4:12 roof pitch facing dead south.
Unfortunately Tim you may have to wait until late spring or early summer to see how well you system performs? Since we (Denver) will have close to 12 to 14 hour days or sunshine your system should be maxing out pretty much. This will give you a good baseline of what the max your system should be producing daily. I exported a copy of my June 2021 production since this was the month that my system produced the maximum amount of energy for 2021. I would think this would give me and you the best bench mark to see if your system is running at max production?

1644593919922.png
 

nakman

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Ray are you able to see your wattage production in real time? Then compare that to what your system should add up to? Curious if you also cap at 75%.
 

RayRay27

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Ray are you able to see your wattage production in real time? Then compare that to what your system should add up to? Curious if you also cap at 75%.
No that's one of the big issues that I have with Sunrun. I have to wait until the next day most of the time to see my output. I guess if I contacted Sunrun they could tell me what the hourly production rates are but I haven't done that yet. So if you see my chart below it stops at 3-4pm. That's because the system hasn't updated yet. So later this afternoon when I check back it should show that the system last updated at 9pm last night (2/10/2022). Again that's one of the biggest caveats with solar. You almost have to go through an entire year to make sure your system is producing what it was designed for.
1644596592434.png


1644596457466.png
 

rover67

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mine is in real time what do you want to see?
 
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