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Yonki

Member
Supporting Member
Mar 31, 2015
629
1,815
Pacific Grove, CA
I got a 4kW Solar / 1 Powerwall system installed in my old house in 2018. SolarEdge inverter and optimizers, generic panels. I was overall pretty disappointed - 2 days after the install a fault in the gateway made me lose all power (PG&E and/or solar/battery) to my house, and I spent 2 hours with a Tesla tech tech who told me again and again that it simply can't possibly be Tesla's fault before he finally sent a tech over who fixed it (it was the Tesla gateway as I had said). Also, they switched me to the wrong rate plan, so I had a true-up BILL of $1,500 after the first year. And I tried to get access to SolarEdge's more detailed view on their app, but Tesla was not cooperative. But I did love having the Powerwall (we have minor power outages several times a year, plus PG&E's occasional intentional blackouts).

Well I'm in a new, bigger house now (thank you $TSLA) and looking at a 12kW/3 Powerwall system. After my previous experience, I'd at least be open to systems from other suppliers, but I figure the only way I'm getting 3 Powerwalls in early 2021 is through Tesla, so I'm going with them, despite being generally disappointed with Tesla Solar support & their general attitude. They seem determined to take the fun out of owning solar.

I'm trying not to repeat the same mistakes, so I inquired about getting SolarEdge access, figuring this is when I have the most leverage. They said they're not using SolarEdge inverters anymore, they're using Deltas. Fine, so I ask whose microinverters/power optimizers will they be using, and they replied
Tesla is no longer using optimizers or micro inverters. The individual panel monitoring is no longer available.

Like I said, Tesla wants to take all the fun out of it.

Since I don't think I'm going to get a useful answer from my solar "Project Advisor", I thought I'd ask here: How the **** do you build a solar system with standard 330W panels with no microinverters or optimizers? I don't see how it's possible without some kind of panel balancing and panel bypass/disconnect for bad panels, which as far as I can imagine requires some form of optimizers or micro inverters.

So has anyone here had a recent install that uses a Delta Mxx-TL-US inverter and can tell me how they work this magic or if they're just lying to me?

And if anyone has a solar advisor they actually enjoyed working with, I'd love it if you would PM me their contact info and I'll see if I can switch over (I won't tell them where I got their name unless you want me to).

Cheers.
 
We just did a 16KW system with 3 PWs through Tesla- install was 12/3-12/4. Each 340 watt panel had an optimizer and we have SolarEdge inverters. I'm in NY so I don't know if they are doing things differently on that coast. Our local team was great to work with and very responsive but the original guy who works wherever CS is based was not very responsive.
 
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CA 4.08kW/1PW system ordered 9/5, installed 12/10.

12 340W panels with a solaredge inverter and power optimizers on each.

From my recent browsing on the forum, I believe my advisor was much better than most. Probably not the MOST knowledgeable, but regularly responded to emails within 1 business day and reached out to others at Tesla to get answers if needed. PM if you want the contact information.
 
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There's a huge firmware issue with the Delta M series currently.

If there's a tiny bit of light fluctuation on a single panel the entire inverter will shutdown for 20 minutes. So say you have scattered clouds you inverter will basically not produce at all. This is a known issue but Delta hasn't fixed the firmware yet and Tesla is still installing this combo of inverters and MCIs.

Tell them you don't want the Delta unless they have a firmware fix.

More info: Inverter Shutting Down
 
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Thanks Lucas - I'll definitely let them know that I won't accept a Delta inverter until I hear from my friend Lucas that Tesla has ironed out all the issues with his system. (Maybe that will even help your situation a tiny bit.)

I haven't even bought it yet and I'm already starting to regret buying a new Tesla solar setup... As a big fan, shareholder, and a Model 3 owner (and soon a Model Y for my wife), it really pisses me off that Tesla's solar service and support can be so abysmal.

What's an MCI?
 
I got a 4kW Solar / 1 Powerwall system installed in my old house in 2018. SolarEdge inverter and optimizers, generic panels. I was overall pretty disappointed - 2 days after the install a fault in the gateway made me lose all power (PG&E and/or solar/battery) to my house, and I spent 2 hours with a Tesla tech tech who told me again and again that it simply can't possibly be Tesla's fault before he finally sent a tech over who fixed it (it was the Tesla gateway as I had said). Also, they switched me to the wrong rate plan, so I had a true-up BILL of $1,500 after the first year. And I tried to get access to SolarEdge's more detailed view on their app, but Tesla was not cooperative. But I did love having the Powerwall (we have minor power outages several times a year, plus PG&E's occasional intentional blackouts).

Well I'm in a new, bigger house now (thank you $TSLA) and looking at a 12kW/3 Powerwall system. After my previous experience, I'd at least be open to systems from other suppliers, but I figure the only way I'm getting 3 Powerwalls in early 2021 is through Tesla, so I'm going with them, despite being generally disappointed with Tesla Solar support & their general attitude. They seem determined to take the fun out of owning solar.

I'm trying not to repeat the same mistakes, so I inquired about getting SolarEdge access, figuring this is when I have the most leverage. They said they're not using SolarEdge inverters anymore, they're using Deltas. Fine, so I ask whose microinverters/power optimizers will they be using, and they replied

Like I said, Tesla wants to take all the fun out of it.

Since I don't think I'm going to get a useful answer from my solar "Project Advisor", I thought I'd ask here: How the **** do you build a solar system with standard 330W panels with no microinverters or optimizers? I don't see how it's possible without some kind of panel balancing and panel bypass/disconnect for bad panels, which as far as I can imagine requires some form of optimizers or micro inverters.

So has anyone here had a recent install that uses a Delta Mxx-TL-US inverter and can tell me how they work this magic or if they're just lying to me?

And if anyone has a solar advisor they actually enjoyed working with, I'd love it if you would PM me their contact info and I'll see if I can switch over (I won't tell them where I got their name unless you want me to).

Cheers.

If you order this month, I know some contractors like the one I work for are still offering installs in the first half of 2021. You're welcome to go through Tesla if that's your preference. PM me if you are interested.

You have little leverage to get your specifi needs met with Tesla but perhaps your needs are better served by another. Plus the Large Scale SGIP is available for 3-5 Powerwalls, so the price is similar to other installers who don't apply for it.
Don't let them ruin all the fun!
 
String inverters. We have 50x 350W panels on 5 strings. No microinverter/optmizers. This is a pole-mount though, so if needed it's possible to test panels from the back.
String inverters? Don't they have this problem:
string inverter.jpg

That's fine if all your panels see the same sun all the time, but in my case some of the panels will be shaded during different parts of the day, so if that's what they're proposing, it's a hard no for me.
 
Thanks Lucas - I'll definitely let them know that I won't accept a Delta inverter until I hear from my friend Lucas that Tesla has ironed out all the issues with his system. (Maybe that will even help your situation a tiny bit.)

I haven't even bought it yet and I'm already starting to regret buying a new Tesla solar setup... As a big fan, shareholder, and a Model 3 owner (and soon a Model Y for my wife), it really pisses me off that Tesla's solar service and support can be so abysmal.

What's an MCI?

It has something to do with the rapid shutdown system which is required in some states. If I have it correctly the MCI are little boxes that connect directly to a group of 4 panels and look for electrical faults. If they sense an issue they shutdown the inverter.
 
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String inverters? Don't they have this problem:
View attachment 619093
That's fine if all your panels see the same sun all the time, but in my case some of the panels will be shaded during different parts of the day, so if that's what they're proposing, it's a hard no for me.

Tesla never has done microinverters to my knowledge. people reported here them doing optimizers all during 2020 though but tesla changes stuff all the time.

There are plenty of us without optimizers / microinverters whose systems work just fine though so that is not a "mandatory" necessity for a functioning system. Depends on where you are, shading etc. You mention you have shading so maybe optimizers would be necessary for you.


Based on what you are saying, its likely you want to at least check out other suppliers.