Does Tesla honor Silevo panel warranties?

[Steeler.Fan]

I previously described my system in my "How much variation in panel output is normal?" post. Basically, it consists of 24 panels (13 Silevo 305w and 11 Panasonic 325w) with SE6000A inverter and p400 optimizers. I have observed a fair amount of variation between the panels within each brand. One reason why I was interested in the normal amount of variation was because it appeared that the Silevo panels were underperforming compared to the Panasonic. Without radiation data, it appeared to be impossible to know whether my Silevo panels were performing below their warranty level of performance. I recently learned of a site called Solcast which offers estimates of solar radiation as well as power predictions.

https://solcast.com.au/solar-data-api/forecasts-vs-estimated-actuals/

https://www.solarquotes.com.au/blog/how-to-use-solcast/?utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A+SolarPowerPanels+%28Solar+Power+Blog%29

They "use images of clouds taken by weather satellites and a series of modelling steps to produce estimates of the available solar radiation at any given location. These values are updated by Solcast with each new satellite scan every 10 to 15 minutes. Solcast continually calibrates and improves estimated actuals against surface measurements."
They offer an API, which is free to hobbyists and solar enthusiasts, where one can enter your location, array capacity (DC kW), tilt, azimuth and longitude and latitude and it will generate a table of estimated power from your array. You can compare their estimates with your outputs from your inverter to estimate your system's degredation and add &loss_factor= to your API request to refine your estimates. Alternately, I could divide my reported energy by my expected energy output to determine and compare the relative degredations of my 2 brands of panels.

Since I have 2 types of panels, I would need to perform the calculations for each sets of panel. My SE monitoring site provides production data for each panel so I can calculate the reported production from each panel (of known brand) per day and compare it to the Solcast estimates.

Can I use this data to evaluate the performance of my Silevo panels?
If they appear to be performing below the warrantied level, will Tesla (who bought SolarCity who bought Silevo) honor a warranty claim for Silevo panels?

I look forward to your expert feed back and comments.

[bcroe]

In my experience clouds are so variable in both predictions and in actual operation, no
very accurate numbers can be measured. I would say you would need to have an accurate
gauge of the radiation hitting the panel, and even that is harder because the clouds want
to change while you are making the measurements.

What does work here, is to have panels in identical setups, comparing their outputs at any
instant. Alternately compare their energy collected over time, if no shading interferes.

Bruce Roe

[J.P.M.]

That SOLCAST site looks a little scammy prone to me and short on particulars. Why not compare an array's output/STC kW to that of similar orientation/location outputs from PVOutput. ?

FWIW, I've been comparing my array's actual (inverter monitored) output at 5 min. intervals for the last 5 + years, adjusted it for cell temps. and for irradiance from a Davis Pro II+ with a pyranometer. The goal is to monitor array fouling as f(time, weather variables). Once the GHI from the Davis is converted to POA irradiance, and the array's theoretical temp. and irradiance adjusted output are calc'ed, that output can be compared to actual. If you're serious about cell/panel/array performance, an on site pyranometer is the best way to get the actual irradiance.

[darren_solcast]

Hi J.P.M,

I can assure you Solcast isn't a scam (disclaimer, I'm a developer at Solcast). Details about our method are documented on our site and also papers published with our data from the ANU (Australian National University).

We use a combination of numeric weather models and live satellite updates to track clouds and most importantly their thickness.

The resolution of most locations around the world are between 1-3km so results for satellite based historicals are pretty good. We model radiation (GHI, DNI, DHI etc) hitting the surface and then model the conversion to power.

Feel free to check our front page demo. It is using live 30 minute data globally which updates between every 10-15 minutes.

Hope that helps.

[J.P.M.]

Hi J.P.M,

I can assure you Solcast isn't a scam (disclaimer, I'm a developer at Solcast). Details about our method are documented on our site and also papers published with our data from the ANU (Australian National University).

We use a combination of numeric weather models and live satellite updates to track clouds and most importantly their thickness.

The resolution of most locations around the world are between 1-3km so results for satellite based historicals are pretty good. We model radiation (GHI, DNI, DHI etc) hitting the surface and then model the conversion to power.

Feel free to check our front page demo. It is using live 30 minute data globally which updates between every 10-15 minutes.

Hope that helps.

So, what can you do for me or anyone that can't be done with a pyranometer and some verified model(s) except conform/refute locally acquired data ? Given the number of (local) variables you don't monitor seems a reliable/tested model and a weather station can do as well or better. Performance estimates and modeling of residential systems are not that complicated, nor do they need to be. I can do as well as you can or better without your stuff, as can anyone else.

[darren_solcast]

Hi J.P.M,

It depends what people need. The question "How much variation in panel output is normal?" from the OP can be done via our service via a browser or access to our API. To a lot of people we have found this to be quite a value add as the cost of entry/effort put in by the person doing the validation is a a LOT smaller than buying, calibrating, collecting data from their own pyranometer for analysis.

I would put forward that live performance modeling based on cloud movements/thickness is not a simple problem for lots of individuals to solve. I understand this service doesn't meet everyone's needs but many people have found it quite useful for a simple check if their panels are performing as expected. For example,

https://www.solarquotes.com.au/blog/how-to-use-solcast/

Loads of other uses for the services we provide used by companies all over the world but I agree there are going to be lots of use cases where this might not be applicable and a different solution would be needed.

[J.P.M.]

Hi J.P.M,

It depends what people need. The question "How much variation in panel output is normal?" from the OP can be done via our service via a browser or access to our API. To a lot of people we have found this to be quite a value add as the cost of entry/effort put in by the person doing the validation is a a LOT smaller than buying, calibrating, collecting data from their own pyranometer for analysis.

I would put forward that live performance modeling based on cloud movements/thickness is not a simple problem for lots of individuals to solve. I understand this service doesn't meet everyone's needs but many people have found it quite useful for a simple check if their panels are performing as expected. For example,

https://www.solarquotes.com.au/blog/how-to-use-solcast/

Loads of other uses for the services we provide used by companies all over the world but I agree there are going to be lots of use cases where this might not be applicable and a different solution would be needed.

After looking at your reference and your other stuff, I haven't seen anything that would change my opinion that your product is not worth the price - whatever it may be as I couldn't find any information about what it costs.

Furthermore, similar to giving a loaded handgun to a two year old, I am of the opinion that your stuff in the hands of most folks will have some probability of leading to bad endings, or at least send them off in less than optimum paths with what's likely to be false confidence that the information your product might supply is reliable in some sense.

I am further of the opinion your stuff is no better at performance estimates than commonly available (and free) products and commonly available methods.

But, tell you what, I've got 5 minute data on my system's output and also weather data including GHI in 1 min. increments since my array went live on 10/13/2013. I've got the system operating parameters dialed in quite well, and I have a boatload of other analysis on the array's performance as well. If you tell me via a post to this thread what you need to estimate what my array's daily output has been since startup, I'll post that information and you can test your product. You can then post what your product came up with for an estimate of my actual output for the period, or any sub periods. I'll then post my array's output for the same period and we can all compare. I'd suggest a total output in kWh since startup and maybe annual totals on a date of your choosing to keep the data size within reason.

Until then, I'd also respectfully suggest the mods consider deleting the link you include as it's little more than advertising a product that I believe to be not worth whatever it costs.

[Ampster]

After looking at your reference and your other stuff, I haven't seen anything that would change my opinion that your product is not worth the price - whatever it may be as I couldn't find any information about what it costs.
.........
...... not worth whatever it costs.

Here is a quote from that site, "Solcast is a super handy, FREE, quick and accurate way to check what your solar power system should have produced in the last 7 days." {Caps mine)

[J.P.M.]

Here is a quote from that site, "Solcast is a super handy, free, quick and accurate way to check what your solar power system should have produced in the last 7 days."

Yes Ampster, I've seen that and most of the other stuff associated with that outfit. The adjectives used to "check" output are, IMO, inaccurate and deceptive.

You continue to presume your input reveals some new and previously unknown information. I wish to assure you, it does not.

I need your input about as much as I need a rash.

Your grasp of the obvious is astounding.

[darren_solcast]

Hi J.P.M,

I can understand your skepticism, but feel follow the article and get access to the data yourself. We are improving the websites messaging around pricing, there are a lot of B2B services we currently do but are trying to make our services more easily accessible to hobbyists/researchers. Currently we have a number of hobbyists who manage their home batteries using our forecast data.

To use our API you'll need the following metadata about your own system.

- Location (latitude/longitude)
- Capacity of your panels (if your system is oversized, current publicly available endpoint doesn't cater for inverter clipping)
- Direction (Azimuth) of your panels (180/-180 in our system usually for sites in North America (facing south)
- Tilt of your panels (degrees)
- Efficiency/loss factor of your system to adjust for age of system and other factors that might impact output efficiencies

Here is an example call to our API to get the last week of output (this is all described in the article link)

https://api.solcast.com.au/pv_power/estimated_actuals?longitude=-117.1&latitude=33.2&capacity=5000&azimuth=180&install_date=20131013

I don't know how big your system is so populated the above based on your profile information. Have attached our 30 minute average output (averaged to the period end) if that helps.

We also provide radiation if you want to compare raw GHI or other radiation outputs.

https://api.solcast.com.au/radiation/estimated_actuals?longitude=-117.1&latitude=33.2

I've attached results of these calls above for your convenience but live data is available any time and updates every 15 minutes over the US thanks to the GOES-16 satellite.

The approach of using satellite data to derive surface radiation allows a much wider use of forecasting solar power production into large electricity networks. This would be prohibitively expensive if done with thousands of pyranometers installed. This data won't be as precise good quality, well maintained hardware on the ground but has proven to be useful in a lot of situations to lot of people.

I probably won't post here again. Feel free to delete my posts, was trying to look for places our data would help hobbyists/researchers who can make use of our data for free as there is no shortage of work in the renewables space and solar is becoming more and more important. All the best.

[J.P.M.]

I probably won't post here again. Feel free to delete my posts, was trying to look for places our data would help hobbyists/researchers who can make use of our data for free as there is no shortage of work in the renewables space and solar is becoming more and more important. All the best.

Feel free to post/not as you wish. I have no say in such things and glad of it.

Also, since you seem to have declined my offer of comparison of prior data, similar in concept anyway, to the way Clean Power Research collaborates with GroundWork Renewables, I take it you won't be phishing around here for leads any more.

(See the 2014 American Solar Energy Conference proceedings : "REDUCING PROJECT UNCERTAINTY WITH AN OPTIMIZED RESOURCE ASSESSMENT TUNING TECHNOLOGY".)

FWIW, your outfit looks to me like it's a rehash of outfits like Clean Power Resaerch (Dick Perez's outfit that brought us the SolarAnywhere satellite data concept), or others peddling repackaged satellite data. How many more such outfits are necessary ?

I don't know your true motives for posting here, but feel you are here to drum up business and self promote rather than help anyone.

As for the future of solar or other non fossil fuel energy sources - and I hope it's a bright and helpful one to the planet as much or more than anyone hopes - I feel it'll be a better and more successful future if it doesn't have to drag with it the anchor of opportunists of the type I feel you and your outfit seem to exemplify.

Just my opinions.

Respectfully and sincerely,

J.P.M.

[Ampster]

.......
Your grasp of the obvious is astounding.

Obvious? To be clear, I was merely trying to respond to your comment that you could not find any information about pricing. The quote I provided showed that it was free.

[J.P.M.]

Obvious? To be clear, I was merely trying to respond to your comment that you could not find any information about pricing. The quote I provided showed that it was free.

That's B.S. Looks to me like you're not using your head. The quote you provided showed that the Solcast website stated it was free. I saw the same statement. Do you believe everything you read ? If you believe meaningful, useful and complete information is free from Solcast to folks who know how to make use of it (and I'm pretty sure you ain't one of them BTW), then I've got bridges for sale. Besides, my guess is you're clueless about what their product actually proports to provide, or that such information already exists from other sources, some of which are (or seem to be) free under some circumstances. See the SolarAnywhere/NREL links. Same stuff.

The trial or example Solcast offers may be no cost moneywise, at least at the beginning. But I've seen too much similar stuff as has most everyone else, except maybe you it seems. Solcast is not a pro bono outfit. And that's not a knock on them for attempting to drum up business from the ignorant - it's just business - even if that's what they're doing.

The reality: Find me what you get for free from Solcast in a clear and unambiguous way without divulging to them who you are. Whether you know it, or believe it, or not, such free offers as they cryptically without details offer are most likely come-ons and hooks to trap fools. Do the "Call for pricing", or "free trial", etc. and you'll never get any peace. Contact them, and you, and your information, become a fungible lead for anything/anyone dealing with or peddling alternate energy products - scam or not. That's another reason, separate from money, why it ain't free.

As for my post to you, I was referring to what I see as your inability to grasp - as most anyone who read my posts would probably infer - that I had already read through the Solcast website and other linked information supplied therein as would (hopefully) be obvious to anyone who bothered to read my post : My statement "After looking at your reference and other stuff..." might be a giveaway (besides, where/how else would I have gotten the information contained in my reply to Darren_Solcast ?) Then you come along and tell me what I've already read. Use your head.

As for Solcasts bill of goods, you may be one of those who see what they want to see in whatever way(s) make their lives easier, or conforms to what they've already made up their minds fits their notion of reality. Or, you may have a need to input something here to get attention or some other reasons I know nothing about and care less.

I've found that free is a tempting proposition that people want to believe in because it makes for an easier vision of reality, but like the tooth fairy and Santa Claus, doesn't exist in the world I live in.

[Ampster]

That's B.S. Looks to me like you're not using your head.

No need to make this personal. My comment was addressed to the hundreds of lurkers who never post. I have no interest in this product and only read the description out of curiosity. Ironically the unintended consequence of your rants might be that those lurkers may also have had their interest piqued.

As for my post to you, I was referring to what I see as your inability to grasp - as most anyone who read my posts would probably infer - that I had already read through the Solcast website and other linked information supplied therein as would (hopefully) be obvious to anyone who bothered to read my post : My statement "After looking at your reference and other stuff..." might be a giveaway (besides, where/how else would I have gotten the information contained in my reply to Darren_Solcast ?) Then you come along and tell me what I've already read. Use your head.

Again, this is not about you and I am sorry that you took this so personally.

As for Solcasts bill of goods, you may be one of those who see what they want to see in whatever way(s) make their lives easier, or conforms to what they've already made up their minds fits their notion of reality. Or, you may have a need to input something here to get attention or some other reasons I know nothing about and care less.

Care less? Good advice that I would agree we should all follow.

[Mike90250]

OK, settle down. Everyone's a tad touchy here, and we've been warned about "free" stuff.