How many panels are actually generating solar power?

[SolarBob]

I have 42 340W (I think they are 340 W) Tesla HE Solar Panels on my roof, powered with 2 inverters. It is midday here in Northern California, and my Solar Production is 7.5 kW.

The solar panels are in different locations on the roof facing different directions based on my roof.

So 42x340 watts = 14.3 kW

Does that mean that only half of my panels are producing power?

Does this seem like perhaps something might be wrong.

Comments?

 

[jjrandorin]

I have 42 340W (I think they are 340 W) Tesla HE Solar Panels on my roof, powered with 2 inverters. It is midday here in Northern California, and my Solar Production is 7.5 kW.

The solar panels are in different locations on the roof facing different directions based on my roof.

So 42x340 watts = 14.3 kW

Does that mean that only half of my panels are producing power?

Does this seem like perhaps something might be wrong.

Comments?

Since you ask for comments... it doesnt work that way (you dont simply add up the rating of your panels and think that your system will produce that amount of electricity.

There isnt enough information for anyone to take a guess on whether something might be wrong or not, but my gut feeling says no. For one thing, forget about the size / capacity of your panels. What is your inverter size(s)?

Second, go to PVwatts, put in as much information as you can on your system, and see what it estimates your production will be. It wont be the sum total of your panel capacity though, unless all of your panels are facing south, at the perfect angle, which you said they arent.

 

[h2ofun]

I have 42 340W (I think they are 340 W) Tesla HE Solar Panels on my roof, powered with 2 inverters. It is midday here in Northern California, and my Solar Production is 7.5 kW.

The solar panels are in different locations on the roof facing different directions based on my roof.

So 42x340 watts = 14.3 kW

Does that mean that only half of my panels are producing power?

Does this seem like perhaps something might be wrong.

Comments?

Depends on direction, shading,etc!. I never get near the "spec" because of these issues

 

[MXLRplus]

A clean panel on a cloudless day at noon in the summer with zero shade the day it's sold will hit the advertised number if you have aimed it right.
For 3 months out of the year, I hit >80% of my advertised rating, the rest of the year is less, but I aimed them specifically for summer output.
Today I reached 17.99 kW of a 24.2 kW (advertised watts, 4 years old) or 74% of advertised.
But mine are mounted on a flat roof at 11° aimed at the southwest for late day production in the summer.

 

[charlesj]

I have 42 340W (I think they are 340 W) Tesla HE Solar Panels on my roof, powered with 2 inverters. It is midday here in Northern California, and my Solar Production is 7.5 kW.

The solar panels are in different locations on the roof facing different directions based on my roof.

So 42x340 watts = 14.3 kW

Does that mean that only half of my panels are producing power?

Does this seem like perhaps something might be wrong.

Comments?

As indicated, insufficient information.
But, to start with, the data is your advertised DC power under lab test conditions, not real world condition. I have read someplace that it is a flash test.

Then, the inverter is your main restriction point. It will not produce beyond its rated continuous output.
Then comes time of year, panel orientation and tilt. Then comes shading and when that happens how much that will matter. No shading at peak sun angle, no effect on power at that point, that comes when it is shading.

 

[SolarBob]

Thanks to all for the input. Talked to Tesla, and there is no way for them to determine if you have a couple of panels not working.

They say it is something you probably would not notice. I have SolarEdge inverters installed in Dec, without the display so there is no way for me to log in to the unit.

To me it is important if some of my panels are not working to spec. Tesla should do something about this.

Thank you,

It appears I am getting good Solar Energy but who knows.

 

[jjrandorin]

Thanks to all for the input. Talked to Tesla, and there is no way for them to determine if you have a couple of panels not working.

They say it is something you probably would not notice. I have SolarEdge inverters installed in Dec, without the display so there is no way for me to log in to the unit.

To me it is important if some of my panels are not working to spec. Tesla should do something about this.

Thank you,

It appears I am getting good Solar Energy but who knows.

You should be looking at your system compared to information you put into PVwatts (or estimated yearly production) over months time, not days. You should have a document somewhere with estimated YEARLY production from tesla. Know that your system will generate a lot more energy from march - october than it will nov - Feb.

Looking at a snapshot of your daily production isnt going to give you much information, unless you already had data on what that should look like (as in it was installed last year, and april of last year was X production, and now its X-30% this year, with similar weather).

 

[holeydonut]

IMO, this thread helps reinforce one of the benefits that Enphase microinverters offers instead of big azzz wave inverters (with optimizers) and string inverters. I can look at a panel by panel ramp up and detect any anomalies that don't pass the sniff test. Naturally if one panel + inverter combo is underperforming another that sits next to it, then there's a strong chance something is amiss.

The downside is with dozens of microinverters, is the chance of one or more dying during the lifetime of the system is high. I guess it's a trade-off between a very high chance of a failure... but with nominal impact compared to a lower chance of individual failure... but with lots of uncertainty if there is a problem.

FWIW, I'm achieving my nameplate maximum on a per-panel basis at high noon in East Bay Norcal. I would assume my neighbors would do the same with panels that face mostly South now.

 

[fragchild]

Thanks to all for the input. Talked to Tesla, and there is no way for them to determine if you have a couple of panels not working.

They say it is something you probably would not notice. I have SolarEdge inverters installed in Dec, without the display so there is no way for me to log in to the unit.

To me it is important if some of my panels are not working to spec. Tesla should do something about this.

Thank you,

It appears I am getting good Solar Energy but who knows.

There are ton of threads here on how to get a SolarEdge account and see your individual panel data.

 

[jjrandorin]

There are ton of threads here on how to get a SolarEdge account and see your individual panel data.

Thats only relevant if the inverter is a solar edge, which tesla isnt installing right now.

 

[dareed1]

The OP said he has SolarEdge.
@SolarBob: PVWatts is an excellent program, but it uses a weather model that varies daily to estimate solar production over time. That's great for planning annual output, but what you need now is an estimate of clear day production at peak. That way you can quickly tell if your system is up to snuff. I can make that estimate (so can others, I believe), but to do so, we need to know the pitch of your roof, the direction each of your arrays face, and the number of panels in each array. The layout Tesla sends to homeowners has the angle of the roof (for example, ours is 27 degrees), and the directions the panels face also in degrees. Just saying South or West isn't enough unless the house really is aligned with these directions. A ZIP code would be good also. Finally, we need the sizes of your inverter.

 

[jjrandorin]

The OP said he has SolarEdge.
@SolarBob: PVWatts is an excellent program, but it uses a weather model that varies daily to estimate solar production over time. That's great for planning annual output, but what you need now is an estimate of clear day production at peak. That way you can quickly tell if your system is up to snuff. I can make that estimate (so can others, I believe), but to do so, we need to know the pitch of your roof, the direction each of your arrays face, and the number of panels in each array. The layout Tesla sends to homeowners has the angle of the roof (for example, ours is 27 degrees), and the directions the panels face also in degrees. Just saying South or West isn't enough unless the house really is aligned with these directions. A ZIP code would be good also. Finally, we need the sizes of your inverter.

You are right, I missed that. Since its solar edge inverters the OP can work through the "solar edge access" process in a few of the threads here, to see their production

 

[charlesj]

...

The downside is with dozens of microinverters, is the chance of one or more dying during the lifetime of the system is high. ...

I had one of 17 go out in 9 years not that long ago. Now the replacement inverter is the best producer.

 

[bob_p]

Our 3rd party Tesla-approved installers used Chilicon Power microinverters (one inverter per two panels). The system came with a monitoring panel installed in our garage next to the PowerWalls. On that panel, we can view the power output from each pair of panels.

During the day - the panels getting full sun are lit red with other colors showing lesser amount of solar. There is also a web interface that can be used to display graphs showing the power output for all of the microinverters (you can select which ones to display).

So it's easy to watch the panels activate, generate power, and then start losing power during the day as the sun moves across the sky.

And if we are having problems with any microinverters or panels, we'll be able to see that on the display and then use the web interface to get more detail - before contacting our installers to have them come out and investigate.

 

[charlesj]

Our 3rd party Tesla-approved installers used Chilicon Power microinverters (one inverter per two panels). The system came with a monitoring panel installed in our garage next to the PowerWalls. On that panel, we can view the power output from each pair of panels.

During the day - the panels getting full sun are lit red with other colors showing lesser amount of solar. There is also a web interface that can be used to display graphs showing the power output for all of the microinverters (you can select which ones to display).

So it's easy to watch the panels activate, generate power, and then start losing power during the day as the sun moves across the sky.

And if we are having problems with any microinverters or panels, we'll be able to see that on the display and then use the web interface to get more detail - before contacting our installers to have them come out and investigate.

Can you monitor it on a computer or phone app?

 

[5150Code3]

Thanks to all for the input. Talked to Tesla, and there is no way for them to determine if you have a couple of panels not working.

They say it is something you probably would not notice. I have SolarEdge inverters installed in Dec, without the display so there is no way for me to log in to the unit.

To me it is important if some of my panels are not working to spec. Tesla should do something about this.

Thank you,

It appears I am getting good Solar Energy but who knows.

Since you have a SolarEdge inverter, contact Tesla and ask them to contact SolarEdge and request SE to set up an account for you. I did this and 3 days later had an account with panel level generation data. Note that Tesla will not provide support for SE account issues.

 

[bob_p]

Can you monitor it on a computer or phone app?

Last time I checked, they don't have an app.

I can check it using a web browser at home and via VPN or remote desktop (to a computer at home) when away from home.

 

[sorka]

Thanks to all for the input. Talked to Tesla, and there is no way for them to determine if you have a couple of panels not working.

They say it is something you probably would not notice. I have SolarEdge inverters installed in Dec, without the display so there is no way for me to log in to the unit.

To me it is important if some of my panels are not working to spec. Tesla should do something about this.

Thank you,

It appears I am getting good Solar Energy but who knows.

Log into your SE monitoring portal and look at your panel level production.

 

[sorka]

IMO, this thread helps reinforce one of the benefits that Enphase microinverters offers instead of big azzz wave inverters (with optimizers) and string inverters. I can look at a panel by panel ramp up and detect any anomalies that don't pass the sniff test. Naturally if one panel + inverter combo is underperforming another that sits next to it, then there's a strong chance something is amiss.

The downside is with dozens of microinverters, is the chance of one or more dying during the lifetime of the system is high. I guess it's a trade-off between a very high chance of a failure... but with nominal impact compared to a lower chance of individual failure... but with lots of uncertainty if there is a problem.

FWIW, I'm achieving my nameplate maximum on a per-panel basis at high noon in East Bay Norcal. I would assume my neighbors would do the same with panels that face mostly South now.

As long as you have optimizers, which you will if your SE system was installed by Tesla, then you'll still see panel level production. I'd take microinverters over a single inverter in a heartbeat. Yes, a single microinverter could go down but most of your system will never fail. Imagine having your main inverter going down and waiting on Tesla 12 weeks to fix it. Imagine this is the highest producing time of year in the summer. Because of my NEM rate and it's much higher summer peak rate, more than half of the $ amount generated from my system is in just 3 out of 12 months. Going down at just the wrong time for 3 months could cost me nearly $3K.

I'm contemplating buying a second hand SE 7600 on ebay for $1000 as insurance against waiting for months for Tesla to fix a failed inverter should mine go down.

 

[charlesj]

...

I'm contemplating buying a second hand SE 7600 on ebay for $1000 as insurance against waiting for months for Tesla to fix a failed inverter should mine go down.

Will you be able to check to make sure it is operational before a return timeframe runs out? Otherwise you may have a dud on the shelf.