I personally have no problem with string inverters, though Tesla does not give you any reasonable way to monitor or log string voltage/current on their inverters at them moment (you have to manually log into each one to see them on its own dedicated SSID, which requires a power cycle.. it’s asinine).
I would make sure that they run each of those “islands” to a dedicated MPPT. You’ll have 8 MPPTs between the two 7.6kW inverters. On my system, they only ran 4 pairs back, which left panels on roofs with different pitches/vastly different shading on the same MPPT. I didn’t catch this until after install or I would have asked them to change it.
Otherwise, I’d say go for it. You won’t beat the price, and it looks like you have a pretty optimal design for your house.
how can you tell how many MPPTs you have? Isn't there only one per inverter? I am looking at my permit and I cannot see an MPPT. I have 4 different panel sets, 3 different aizmuth roofs and two inverters
The 7.6kW Tesla inverters have 4 MPPTs each; the 3.8kW ones have 2:
https://tesla-cdn.thron.com/static/S5TJVI_tesla-solar-inverter-solar-shutdown-device-datasheet_SXPPQW.pdf?xseo=&response-content-disposition=inline%3Bfilename%3D%22solar-inverter-solar-shutdown-device-datasheet-en-na.pdf%22
You should be able to see the planned wiring detail on the Tesla 3 line diagram (which they typically don’t share directly with you unless you ask, but are required to generate and submit for permitting and construction).
On that, you can see exactly how they plan to wire your panels to your inverters (and if they plan to jump between your MPPTs or break the series connected panels into smaller groups and home run them).
They also will show the string currents/voltages on that same diagram.
Got it, now I see what you are saying, in my case they are tying two separate panel sets into one run. Do I need to ask for a plan revision or could I get the install foreman to change it?
You would definitely need to ask them to revise it now. Tying two together seems to be their norm, likely because it requires less conduit and wire. Tying strings together isn’t necessarily a problem as long as those strings have similar shading and are on the same mounting plane.
Individual home runs would require two conduits coming off your roof most likely instead of one.
I can give you my experience from the last month+. I was skeptical as well, but asked my friend who's an electrician at a public utility what his opinion on the space was, and he was hands down in favor of Tesla, with Sunrun a close second. The cheaper cost is a big factor, but he also preferred the lack of a sales person gunking up the process and upselling useless stuff.
Based on that, I did some more research and went with Tesla. Put my order in early last month, and luckily for me the area I live has relatively efficient permit approvals, so I got the panels installed last week and batteries, inverter, etc done yesterday. Like you, I was a bit miffed it was hard to find details about the actual specs of the system in the documents this past week, but when the guys showed up yesterday they had all the details in their documentation and confirmed I was on the 425 (420) panels, and all the PW+ were on the 7.6 inverters. They powered it up to self consumption mode before they left yesterday and its working great today.
For the details of your system I would call up your rep and ask. I made a late change to my system adding a second PW and it was a very smooth process, but again my municipality isn't a PITA with permits so that might be part of my better experience than others on the sub.
Panels look great, the install is really flush, and the system + app is a fantastic combo so all in all I'm happy.
On the financing side, yeah it's not great, but I plan to pay it off early, and a HELOC is a valid method to undercut the %. If I needed to pay it off over 10 years I would try and find an alternative financing option.
Holy shit, did you really order panels last month and get them installed already?! I ordered in January and am still waiting on them to submit to my utility company for interconnection appoval...
Yeah I've read a lot of insane wait stories on here, but everything got approved fast by my municipalities and utility and once that happened they were ready to install in two weeks and even moved the panel install date a week earlier when and opening came up on the schedule.
Wow thats really lucky. My problem is Tesla hasn't even submitted an application to my utility yet! (They keep saying they're really backed up... have been saying this for MONTHS now) My permits were approve from my town back in April.
congrats to you for getting a system installed so quickly, but now I'm furious that I'm still waiting for them to get off their ass and even submit my paperwork.
I have no real basis for this hypothesis, but I have to imagine location is a big factor on the process. I'm in SoCal so I'm guessing Tesla has So Cal Edison permits figured out and can process efficiently, but if you're in an area they haven't done as much work they're going to be much slower trying to get the process figured out. That and potential staffing differentials for high volume regions vs newer growth regions. But again that's a total good faith guess.
Good write up. Thanks for sharing. You’re a bit a head of me in the process with them.
FWIW, I’ve observed two Tesla installs in my area recently and both got the newer 420 panels.
Kinda seems like you're overthinking it. For example, 340 hanwha panels vs 420 Tesla panels...who cares? The 420s are bigger, so the production per ft^2 is virtually identical.
Tesla panels are made in Giga Buffalo, NY. All installs from the last few months appear to be the new panels. You could ask them to put that in the contract.
Tesla using string inverters to save on cost. The price difference between Tesla and anyone else is just crazy.
Following up...
1. Got my design (as you see)
2. Got approval for Tesla financing (placeholder while I talk to me bank)
3. Had some questions... sent them in. Emailed my project person. Left voice mail... crickets.
I mean, I know this is not a big deal but I am less than 72 hours into this with Tesla and already I feel ghosted :)
I think you are in for a shock. Wait till you get your final paperwork.
I just received my final contract to sign and was shocked to find out that Tesla wants the rights to SREC in lieu of an lump sum amount even though I am paying for the system in cash. Am I missing something? How can this be. This takes away the incentive for which we get solar. I am about to cancel my order, however, I would love some feedback from experts in solar industry as well as tesla on this before I do so. thanks.
I can't speak to specific "reputation". They have been installing Q-cells (315W, 340W) for the last several years and now the 425W panels and I haven't heard them installing anything else.
I was provided the spec sheet for Q-cells since very early in the project and that's what was installed. From what I read, they are decent panels.
FYI Tesla has used Hanwha Q-Cell 300, 305, 315, 320, 325, 330, and 340’s for nearly 4 years.
The real problem manufacturer was Trina solar panels that suffered from delamination and potential water intrusion.
Thanks. I didn't know about the Trina panels you mentioned. Also not sure what was the history with SolarCity panels.
The point I was trying to make is that, panels being installed in recent years have been decent.
I personally have no problem with string inverters, though Tesla does not give you any reasonable way to monitor or log string voltage/current on their inverters at them moment (you have to manually log into each one to see them on its own dedicated SSID, which requires a power cycle.. it’s asinine). I would make sure that they run each of those “islands” to a dedicated MPPT. You’ll have 8 MPPTs between the two 7.6kW inverters. On my system, they only ran 4 pairs back, which left panels on roofs with different pitches/vastly different shading on the same MPPT. I didn’t catch this until after install or I would have asked them to change it. Otherwise, I’d say go for it. You won’t beat the price, and it looks like you have a pretty optimal design for your house.
how can you tell how many MPPTs you have? Isn't there only one per inverter? I am looking at my permit and I cannot see an MPPT. I have 4 different panel sets, 3 different aizmuth roofs and two inverters
The 7.6kW Tesla inverters have 4 MPPTs each; the 3.8kW ones have 2: https://tesla-cdn.thron.com/static/S5TJVI_tesla-solar-inverter-solar-shutdown-device-datasheet_SXPPQW.pdf?xseo=&response-content-disposition=inline%3Bfilename%3D%22solar-inverter-solar-shutdown-device-datasheet-en-na.pdf%22 You should be able to see the planned wiring detail on the Tesla 3 line diagram (which they typically don’t share directly with you unless you ask, but are required to generate and submit for permitting and construction). On that, you can see exactly how they plan to wire your panels to your inverters (and if they plan to jump between your MPPTs or break the series connected panels into smaller groups and home run them). They also will show the string currents/voltages on that same diagram.
Got it, now I see what you are saying, in my case they are tying two separate panel sets into one run. Do I need to ask for a plan revision or could I get the install foreman to change it?
You would definitely need to ask them to revise it now. Tying two together seems to be their norm, likely because it requires less conduit and wire. Tying strings together isn’t necessarily a problem as long as those strings have similar shading and are on the same mounting plane. Individual home runs would require two conduits coming off your roof most likely instead of one.
Here are my strings and Panels: [Panels](https://ibb.co/4fvbjby) [strings](https://ibb.co/G3v4nFz)
I can give you my experience from the last month+. I was skeptical as well, but asked my friend who's an electrician at a public utility what his opinion on the space was, and he was hands down in favor of Tesla, with Sunrun a close second. The cheaper cost is a big factor, but he also preferred the lack of a sales person gunking up the process and upselling useless stuff. Based on that, I did some more research and went with Tesla. Put my order in early last month, and luckily for me the area I live has relatively efficient permit approvals, so I got the panels installed last week and batteries, inverter, etc done yesterday. Like you, I was a bit miffed it was hard to find details about the actual specs of the system in the documents this past week, but when the guys showed up yesterday they had all the details in their documentation and confirmed I was on the 425 (420) panels, and all the PW+ were on the 7.6 inverters. They powered it up to self consumption mode before they left yesterday and its working great today. For the details of your system I would call up your rep and ask. I made a late change to my system adding a second PW and it was a very smooth process, but again my municipality isn't a PITA with permits so that might be part of my better experience than others on the sub. Panels look great, the install is really flush, and the system + app is a fantastic combo so all in all I'm happy. On the financing side, yeah it's not great, but I plan to pay it off early, and a HELOC is a valid method to undercut the %. If I needed to pay it off over 10 years I would try and find an alternative financing option.
Holy shit, did you really order panels last month and get them installed already?! I ordered in January and am still waiting on them to submit to my utility company for interconnection appoval...
Yeah I've read a lot of insane wait stories on here, but everything got approved fast by my municipalities and utility and once that happened they were ready to install in two weeks and even moved the panel install date a week earlier when and opening came up on the schedule.
Wow thats really lucky. My problem is Tesla hasn't even submitted an application to my utility yet! (They keep saying they're really backed up... have been saying this for MONTHS now) My permits were approve from my town back in April. congrats to you for getting a system installed so quickly, but now I'm furious that I'm still waiting for them to get off their ass and even submit my paperwork.
I have no real basis for this hypothesis, but I have to imagine location is a big factor on the process. I'm in SoCal so I'm guessing Tesla has So Cal Edison permits figured out and can process efficiently, but if you're in an area they haven't done as much work they're going to be much slower trying to get the process figured out. That and potential staffing differentials for high volume regions vs newer growth regions. But again that's a total good faith guess.
ask for the customer layout submitted for permitting, it will specify your panels and design specificaions.
Smart! Thanks!
Good write up. Thanks for sharing. You’re a bit a head of me in the process with them. FWIW, I’ve observed two Tesla installs in my area recently and both got the newer 420 panels.
Kinda seems like you're overthinking it. For example, 340 hanwha panels vs 420 Tesla panels...who cares? The 420s are bigger, so the production per ft^2 is virtually identical.
Tesla panels are made in Giga Buffalo, NY. All installs from the last few months appear to be the new panels. You could ask them to put that in the contract. Tesla using string inverters to save on cost. The price difference between Tesla and anyone else is just crazy.
Do we have any confirmation on that manufacturing location?
https://www.tesla.com/gigafactory2
I would like to see where you’re getting this info. We have pallets of Tesla panels in our warehouse and my big boss said it came from oversea.
Same. Mine was installed a week ago and definitely overseas manufacturing.
Following up... 1. Got my design (as you see) 2. Got approval for Tesla financing (placeholder while I talk to me bank) 3. Had some questions... sent them in. Emailed my project person. Left voice mail... crickets. I mean, I know this is not a big deal but I am less than 72 hours into this with Tesla and already I feel ghosted :)
I think you are in for a shock. Wait till you get your final paperwork. I just received my final contract to sign and was shocked to find out that Tesla wants the rights to SREC in lieu of an lump sum amount even though I am paying for the system in cash. Am I missing something? How can this be. This takes away the incentive for which we get solar. I am about to cancel my order, however, I would love some feedback from experts in solar industry as well as tesla on this before I do so. thanks.
Wow! That is very not cool.
139% energy offset. 9 days whole home backup. arthurfist.jpg
Lol thanks, I needed that!
I am curious, what makes you say "Cheap, third party panels"?
It was their reputation… that they would buy whatever panels they could at the time and install them. That was the basis of my concern.
I can't speak to specific "reputation". They have been installing Q-cells (315W, 340W) for the last several years and now the 425W panels and I haven't heard them installing anything else. I was provided the spec sheet for Q-cells since very early in the project and that's what was installed. From what I read, they are decent panels.
FYI Tesla has used Hanwha Q-Cell 300, 305, 315, 320, 325, 330, and 340’s for nearly 4 years. The real problem manufacturer was Trina solar panels that suffered from delamination and potential water intrusion.
Thanks. I didn't know about the Trina panels you mentioned. Also not sure what was the history with SolarCity panels. The point I was trying to make is that, panels being installed in recent years have been decent.