Tesla Solar Panel Design issue (placement of panels)

[howardc888]

I am in SF Bay Area and due to the high electric cost ($.56 peak and $.27 off-peak), I am looking in to Tesla solar panel. Compared to a few other places and Tesla solar is cheaper by quite a bit.

My issue came after the site assessment. Tesla team decided that my roof of rafter sag so they changed the design from front roofs (south facing) to back roofs (north facing). The energy offset decreased from 120%+ to just 78%. I communicated with Tesla team and they say I will need professional engineering stamp to either state my front roof is ok to withstand 3psf or have the sag rafter repair before Tesla can do the install. After spending $1500 to hire a structural engineer (professional engineer), the SE/PE told me the minor sagging is normal for houses around that age. He did his calculation and provided me a letter with stamp stating the roof can take 3psf. I sent it to Tesla for review. And a few days later, the app shows my project changed back to design stage, and a few days later, it now showed the same back roof design of the 78% energy offset. I have scheduled another call with Tesla's project advisor to discuss. But this is frustrating as I already provided evidence showing the roof is ok for the installation but it seems that Tesla just want to avoid liability and won't proceed.

Anyone with similar experience and maybe suggest how you dealt with it (besides dropping Tesla)? I still want to go with Tesla as it is cheapest by a lot and ease of usage of Tesla app and the brand name (more trust worthy).

thanks

 

[jjrandorin]

The only recent thread I remember with a similar issue had Tesla Cancel the entire project:

Solar panels cancelled due to concern over my roof's strength - experiences with this?

Was primed to purchase Tesla solar panels for my 1913 craftsman style home, but after inspection Tesla cancelled. Aggravatingly, Tesla was very reluctant to say why - after much effort, a supervisor explained that there were concerns that the roof wouldn't be sturdy enough to support them. I...

teslamotorsclub.com

If you are not planning on battery storage along with your solar panels, I hope you have really really evaluated whether solar now works to actually reduce your costs in any sort of significant manner.

 

[howardc888]

Forgot to mention I will be get two powerwalls together with solar panels due to NEM3.

 

[karkrazy]

So… this is the typical Tesla experience unfortunately. You have to be the project manager and drive things. And you really, really need to know what you’re buying and what you’re signing up for. Tesla does not like projects with complications or special needs; thus the much lower price point.

If you’re not having much support now, imagine what it’s like post-PTO. Just search TMC for anecdotes. Not trying to convince you otherwise… I know Tesla is way cheaper by far, larger company, etc. But what you pay is what you get. YOU have to be the PM and educate yourself thoroughly.

FWIW, I went with a local company in the Bay Area and have had excellent service the last 3 years (knock on wood ). Email's replied to within the same business day, and they always follow-up with phone calls. Had a problem with an optimizer and a replacement was shipped to me with a week.

However you decide, good luck!

 

[kpanda17]

there are other installers that will install Tesla, there are options
Teslas direct sale, transparency, etc feels cleaner, better, less drama, but there cannot be any complicated install issues
you can also check out dedicated solar forums to find a trusted installer

 

[howardc888]

Just to update on my case (and share the info with people who may have exactly the same issue in the future). So I talked to the Tesla project advisor. (Their turn around time is always like 3-4 days, even for short questions). Apparently, the project advisors did not inform me that besides the 3psf requirement, the deflection of L/120 is also required. Deflection is essentially the degree of roof sag. They now told me that my roof is already over L/120 deflection limit and needs to be addressed before they can work. The deflection requirement was never mentioned initally, and the project advisor's first email to me actually stated that if I can find structural engineer to stamp a letter that my roof meets 3psf requirement, I don't need any repair work on the roof before solar panel installation. I was quite upset that Tesla team did not disclose this to me the first time, so I spent $1500 to get the structural engineer to stamp the letter just to prove my roof is ok. I think this is not going anywhere at this point. The thing is that the structural engineer did his calculation already and said my roof is ok to install solar panels; roof sag may or may not get a bit worse after installation, but it is not a safety concern.

So I have these questions (options) if anyone can help answer:
1. find another solar company to do the south facing roofs - Can anyone share the local solar panel company you used?
2. Even with the reduced energy offset at 78%, the cost is still slightly cheaper than the the two solar panel companies I had. My concern will be that there are 3 redwood trees in neighbor's house blocking the sun in the back roofs. I wonder how accurate is the 78% energy offset. If it produces less, then it does not make sense.
4. The Tesla batteries is also much cheaper. I can prob just do 4.5kW solar panel in the backside + 2 PW (initial design is 9.72kW + 2PW). And in the future, find someone else to add more solar panels on the front roof (south facing) to the Tesla panels on the back roofs (north facing). My concern is if new solar panels can be added on and what are the caveats?

thanks!!

 

[howardc888]

So… this is the typical Tesla experience unfortunately. You have to be the project manager and drive things. And you really, really need to know what you’re buying and what you’re signing up for. Tesla does not like projects with complications or special needs; thus the much lower price point.

If you’re not having much support now, imagine what it’s like post-PTO. Just search TMC for anecdotes. Not trying to convince you otherwise… I know Tesla is way cheaper by far, larger company, etc. But what you pay is what you get. YOU have to be the PM and educate yourself thoroughly.

FWIW, I went with a local company in the Bay Area and have had excellent service the last 3 years (knock on wood ). Email's replied to within the same business day, and they always follow-up with phone calls. Had a problem with an optimizer and a replacement was shipped to me with a week.

However you decide, good luck!

Can you please let me know which one you used? thanks!!

 

[karkrazy]

Did Tesla tell you that the ideal direction for modules (panels) to face is South (#1), East or West (#2), and lastly North. You can try going to PVWatts to estimate your production.

Solar modules (panels) are like Tesla car batteries; they degrade over time and are most efficient at optimal operating temperatures. I was advised last time to get as much as what you want the first time, instead of looking to the future. For one thing, many installers loathe touching another installer’s work. And whether you go with inverters or micro-inverters affects your future options (also your NEM/PTO status).

I’ll DM you about the local installers.

 

[sunwarriors]

Only thing I will add is that I wouldn't expect to add stuff later as most installers won't touch anyone else's system and you will need a totally new, separate system which seems a pain due to more/another ugly box taking up space on your wall, also higher cost, if anyone even wants to bother since it's a smaller job (= less profits).

As suggested, you can simulate an estimate pretty close with PVWatts. You can also get a ton more quotes and see what they say. I assume installers aren't that busy now. I've used Energysage in the past as well and contacted literally every local vendor and got like 15 quotes.

If cost is a major concern for you, I'd even drop to 1 PW and max panels instead first since adding a PW is probably easier, but the PW3 has a diff inverter and your utility may limit what you can do/upgrade so you might be stuck with 1. Since you're on NEM3.0, if you don't have enough panels, you may have trouble charging the PWs up since 4.x seems small. More panels help with cloudy days. Cost for me wasn't much higher not using Tesla, but you have to get much more quotes. I see postings on reddit and don't see insane prices neither ($2-$3/W) even recently.

Also note that there is a proposed $24.95 or something monthly fee on top no matter what you choose to do (get solar or not). I assume "some" monthly fixed fee is coming to CA, how much is still under debate.

Not sure the issue with your roof, but with crazy storms all over the US now, can you fix/replace your roof? If you're open to other solutions, biased me also much prefers the Enphase eco-system as I've never felt Tesla solar home solution was ever better (just cheaper).

 

[jjrandorin]

For one thing, many installers loathe touching another installer’s work.

Only thing I will add is that I wouldn't expect to add stuff later as most installers won't touch anyone else's system and you will need a totally new, separate system which seems a pain due to more/another ugly box taking up space on your wall, also higher cost, if anyone even wants to bother since it's a smaller job (= less profits).

Yeah its pretty much " wont touch ". Maybe some small, hungry solar installer "might" add some panels to another install, but I have never seen anyone have any success at all at getting any installer to add panels to an existing installation. They tend to not even want to do that on their own installs, let alone touch another companies install.

They all want to sell a new system (panels, inverters, etc) that they can then warrant themselves without taking on liability for work they didnt do.

 

[h2ofun]

Yeah its pretty much " wont touch ". Maybe some small, hungry solar installer "might" add some panels to another install, but I have never seen anyone have any success at all at getting any installer to add panels to an existing installation. They tend to not even want to do that on their own installs, let alone touch another companies install.

They all want to sell a new system (panels, inverters, etc) that they can then warrant themselves without taking on liability for work they didnt do.

I had a different installer add another inverter and 45 panels. I guess getting lots of PWs from them helped also.
But, I cannot get them to modify my system for a better solution, even though I would pay whatever it costs.
So bottom line I tell folks, assume whatever you do, max it out, since going back for upgrades is just about impossible!!!

 

[Vines]

Yeah its pretty much " wont touch ". Maybe some small, hungry solar installer "might" add some panels to another install, but I have never seen anyone have any success at all at getting any installer to add panels to an existing installation. They tend to not even want to do that on their own installs, let alone touch another companies install.

They all want to sell a new system (panels, inverters, etc) that they can then warrant themselves without taking on liability for work they didnt do.

This is very true, and also when there is plenty of work, why take on jobs with more risk if you don't have to.

We have just modified our policy on this and will now add PV or ESS to an existing system that was not installed by our company within reason. We will add exclusions to these contracts and also we will do a system health check so that we get a baseline and understand what is on the roof already.

It is definitely a challenge to expand on other systems as not all installers do a great job. There will be cases where a PV system that was 10 years old might only be found to have issues, because the new Powerwall system showed the PV production so easily. The inverter might have been dropping out every day at noon for months, and this was only really realized when the customer started looking at the new fancy Tesla purchase.

 

[h2ofun]

This is very true, and also when there is plenty of work, why take on jobs with more risk if you don't have to.

We have just modified our policy on this and will now add PV or ESS to an existing system that was not installed by our company within reason. We will add exclusions to these contracts and also we will do a system health check so that we get a baseline and understand what is on the roof already.

It is definitely a challenge to expand on other systems as not all installers do a great job. There will be cases where a PV system that was 10 years old might only be found to have issues, because the new Powerwall system showed the PV production so easily. The inverter might have been dropping out every day at noon for months, and this was only really realized when the customer started looking at the new fancy Tesla purchase.

If v3 ever went belly up, since they will not modify my setup for any amount of money, I would hire you and your company in an instant to get my setup to have all the PW's together.

 

[howardc888]

Thanks to everyone who has responded. It really helped me on knowledge building on solar panel purchase. Tesla solar made sense for me initially because the break even time was about just 6-7 years. The process was actually pretty good until I got hit with the roof sag issue. In the Tesla app, Tesla will provide the solar panel design layout, energy produced based on layout (initially there were two to choose from). The app would also show the difference of energy produced on the different roofs ( colored heat map). I did not get solar panel a few years ago because the break even point was 10 year plus. If Tesla would do the north facing roof only, then the break even point is again 10 years +. I think at this point, I should just put the money in stocks instead of in solar panels.