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System gradually producing less and less since installation?

Hello,

Lemme know if there is a better place to post.

Some basic facts:

-Located in Bay Area, Nor Cal

-System installed ~3 month ago

-3 PW+

-25 Panels

The issue I am having is that the system has slowly been producing less and less power each day for the last month. About 1 month ago it pulled down 54K in one day. Yesterday (record setting temps) it only pulled down 30K. That being said it feels like something is wrong and I am looking for some basic feedback and troubleshooting help before I engage Tesla (ugh).

I am new to all of this and have a lot to learn but so far here some reasons why the system might not be producing as much as it used to. I am wondering if anyone has any insight as to what might be going on and would love any advice on how to troubleshoot?

1. Panels are dirty - I have a large landscaping project going on which has involved a lot of excavation and moving around of dirt and gravel etc. Some of this activity has been directly next to the house where the panels are. When I look at the panels they even look dirty. According to research dirty panels can reduce generation by ~3%. Seems like this might be contributing to the problem but certainly does not explain a loss of ~40% . Maybe some of mine are just super dirty?

QUESTION: Can major landscaping around the panels contribute to such a decrease?

2. I have been throttled and am no longer allowed to generate as much power as when it was first installed. To be clear the system has been turned on since Day 1 and I have been feeding back into the grid since day 1. It seems like it was not supposed to be turned on and feeding back into the grid before PTO but thats they way Tesla left it. I charged the car as much as possible to avoid giving power to PG&E for free. The PTO process took 3 months to sort out with much back and forth with both PG&E and Tesla. For some reason I had to send multiple recent PG&E bills to Tesla - probably their own disorganization.

QUESTION: Does Tesla / PG&E limit solar production before the PTO process so as to limit me in what I can generate before PTO? I have read about other people being throttled before the PTO process. I have also read that “the system will not generate as much as it can before PTO is received”. This makes me believe I was being throttled while waiting for the PTO which I just got 1 week ago.

3. The extreme heat spell we are going through is currently effecting how much I can produce. Earlier in the summer is was not as hot. Not its extremely hot which I understand effects the production from the system. I read yesterday that in extreme heat the system can product up to ~%25 less. Seems like this could be a real possibility BUT this morning it was not as hot as yesterday and I was producing a similar amount in the morning.

QUESTION: Are other people in CA seeing a large decrease in solar production during this extreme heat wave?

4. Something is wrong with my system. This seems less likely because the system is brand spanking new AND I can see a gradual decrease over the past month. If something broke in the system I would expect to see that clear drop off at that specific point in time.

QUESTION: Based on the symptoms outlined here does this sound like a system problem? IE something is not working as expected?

Thanks for any and all enlightenment. The timing of this is especially brutal because of the current heatwave. I am now having to pull more from The Grid because my system does not produce as much — which is just backwards.
 

cwied

Active Member
Jan 13, 2015
1,112
830
San Mateo, CA
This is the time of year where production decreases the fastest because days get shorter the quickest at the equinox (in two weeks). The numbers you mention do sound pretty extreme, but between dirt, heat and the shorter days it's not an implausible loss. My system has gone from 39 kWh a month ago to 29 kWh yesterday, but it didn't start out clean like yours did.

You also should check for shading. As the sun gets lower you may get shading that didn't hit the panels during the height of summer.
 
Hello,

Lemme know if there is a better place to post.

Some basic facts:

-Located in Bay Area, Nor Cal

-System installed ~3 month ago

-3 PW+

-25 Panels

The issue I am having is that the system has slowly been producing less and less power each day for the last month. About 1 month ago it pulled down 54K in one day. Yesterday (record setting temps) it only pulled down 30K. That being said it feels like something is wrong and I am looking for some basic feedback and troubleshooting help before I engage Tesla (ugh).

I am new to all of this and have a lot to learn but so far here some reasons why the system might not be producing as much as it used to. I am wondering if anyone has any insight as to what might be going on and would love any advice on how to troubleshoot?

1. Panels are dirty - I have a large landscaping project going on which has involved a lot of excavation and moving around of dirt and gravel etc. Some of this activity has been directly next to the house where the panels are. When I look at the panels they even look dirty. According to research dirty panels can reduce generation by ~3%. Seems like this might be contributing to the problem but certainly does not explain a loss of ~40% . Maybe some of mine are just super dirty?

QUESTION: Can major landscaping around the panels contribute to such a decrease?

2. I have been throttled and am no longer allowed to generate as much power as when it was first installed. To be clear the system has been turned on since Day 1 and I have been feeding back into the grid since day 1. It seems like it was not supposed to be turned on and feeding back into the grid before PTO but thats they way Tesla left it. I charged the car as much as possible to avoid giving power to PG&E for free. The PTO process took 3 months to sort out with much back and forth with both PG&E and Tesla. For some reason I had to send multiple recent PG&E bills to Tesla - probably their own disorganization.

QUESTION: Does Tesla / PG&E limit solar production before the PTO process so as to limit me in what I can generate before PTO? I have read about other people being throttled before the PTO process. I have also read that “the system will not generate as much as it can before PTO is received”. This makes me believe I was being throttled while waiting for the PTO which I just got 1 week ago.

3. The extreme heat spell we are going through is currently effecting how much I can produce. Earlier in the summer is was not as hot. Not its extremely hot which I understand effects the production from the system. I read yesterday that in extreme heat the system can product up to ~%25 less. Seems like this could be a real possibility BUT this morning it was not as hot as yesterday and I was producing a similar amount in the morning.

QUESTION: Are other people in CA seeing a large decrease in solar production during this extreme heat wave?

4. Something is wrong with my system. This seems less likely because the system is brand spanking new AND I can see a gradual decrease over the past month. If something broke in the system I would expect to see that clear drop off at that specific point in time.

QUESTION: Based on the symptoms outlined here does this sound like a system problem? IE something is not working as expected?

Thanks for any and all enlightenment. The timing of this is especially brutal because of the current heatwave. I am now having to pull more from The Grid because my system does not produce as much — which is just backwards.
54kWh —> 30 in one month this time of the year? Something is wrong…sure dirty panels will have an impact but there would have to be a thick layer of dirt to have that impact.

I too am in Nor Cal. My production a month ago was 63 kWh. Yesterday it was 54.8. And that is with 110 degree temps. The heat does have an impact but not a huge one. Last Saturday, an 80 degree day, I produced 59.7 kWh.

i can’t speak to being throttled. I have never been limited in what I can send back to the grid.

Clean your panels and see what happens the next day. Based on your 54kWh produced last month, if you get less than say 50kWh or the high 40’s on a sunny day call tesla or your installer, something isn’t right.
 
Last edited:
I was having my landscaping re-done the past two months with a lot of digging and dirt being moved around many days, causing half my array close to the work being caked in a fine layer of dirt. You cannot compare that to just normal "dirty" panels loss of 3-5%. I eventually was losing about 20-25% of my production, but didn't want to go up a clean them until most of the dirt moving was done, as they would get caked again.

The heat wave also definitely is causing a significant loss in production, which would compound with the dirt-caked panels.
 
  • Helpful
Reactions: BGbreeder

SMAlset

Well-Known Member
Mar 4, 2017
9,396
10,312
SF Bay Area
Could where your PWs are installed be affecting production due to overheating of the PWs (ie if outside in shade or sun). I know there’s a temperature operating range for the units but don’t know it off hand. The wall we had outside near our main panel unfortunately is stucco and sits in afternoon direct sun. Knew it would be blistering hot if installed there. We opted to install in our garage (which we were able to do back in 2020).
 

jboy210

Well-Known Member
Supporting Member
Dec 2, 2016
7,278
4,943
Northern California
Peak solar production for many installations around June 21, the summer solstice. We are now approaching 3 months past that and heading quickly for the lowest sun (shortest day) point Dec 21, the winter solstice. Add that to the heat wave sucking away production and most people's system production is down. And you have dust eating up more solar.
 
Thanks everyone for helping the n00b! I obviously have lots to learn but I think it is safe to say its a combination of all of these things and that the system is working as expected. We cleaned the panels and it made a small difference. The power-walls are on stucco and in direct sun light (literally no other place for them) which does not help. Ill try to shade them somehow.

I think the only factor that I have control of is three large oak trees on the south side of property which now probably cast more of a shadow on the roof. They look like they probably have never been trimmed so I will add that to the short list of things that needs to be done.

Thanks again for the enlightenment.
 
Autumn is the start of decline of solar production in our area, the heat in the last 10 days made it worse. I hope those trees are on your property and there are no restrictions in your county. There are several pine trees south and west just outside my fence that I wanted to nuke but told I would be fined even if they are hazardous as fallen branches had broken my fence before, more than one time.
 

jboy210

Well-Known Member
Supporting Member
Dec 2, 2016
7,278
4,943
Northern California
Thanks everyone for helping the n00b! I obviously have lots to learn but I think it is safe to say its a combination of all of these things and that the system is working as expected. We cleaned the panels and it made a small difference. The power-walls are on stucco and in direct sun light (literally no other place for them) which does not help. Ill try to shade them somehow.

I think the only factor that I have control of is three large oak trees on the south side of property which now probably cast more of a shadow on the roof. They look like they probably have never been trimmed so I will add that to the short list of things that needs to be done.

Thanks again for the enlightenment.
+1 for the trees. We have a very large (60 foot) valley oak in the South of our yard. It starts shading our roof starting about now. By November/December much the South roof will be in shade and the daily production number will be in the mid-teens to single digits. Luckily it drops it leaves in January, and we get a bit more the low sun. It is a great tree, but costs $5-6K every time we get it trimmed. But it is over 100 years old and I am not going to be the guy who kills it.
 
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Reactions: BGbreeder

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Moderator
Nov 28, 2018
16,667
21,947
Riverside Co. CA
Thanks everyone for helping the n00b! I obviously have lots to learn but I think it is safe to say its a combination of all of these things and that the system is working as expected. We cleaned the panels and it made a small difference. The power-walls are on stucco and in direct sun light (literally no other place for them) which does not help. Ill try to shade them somehow.

I think the only factor that I have control of is three large oak trees on the south side of property which now probably cast more of a shadow on the roof. They look like they probably have never been trimmed so I will add that to the short list of things that needs to be done.

Thanks again for the enlightenment.

Welcome to TMC Energy subforum, btw. Hope you choose to stick around with us :)
 
Could where your PWs are installed be affecting production due to overheating of the PWs (ie if outside in shade or sun). I know there’s a temperature operating range for the units but don’t know it off hand. The wall we had outside near our main panel unfortunately is stucco and sits in afternoon direct sun. Knew it would be blistering hot if installed there. We opted to install in our garage (which we were able to do back in 2020).
When it's hot, like it has been the last week or so, my power wall cooling fans make a terrible lot of noise trying to cool the batteries. Sounds like planes taking off. It's just too hot. But to the other question, older panels, dirt, heat, and shading (where you only need a LITTLE shade in one corner to kill the whole panel's production) will easily drop your production. My panels are old and were weak to begin with, and I'm getting only about 11 kwh these days from 66 panels. One of these days I'll have to upgrade, but my house uses only around 13 kwh for only part of the day.
 
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Reactions: SMAlset

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