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Tesla switched inverter to Delta (no optimizers) from promised solaredge (with optimizers)

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Wait, I shut my inverter off and use my Raytek ST-80 on a hot sunny day, I don't see any difference in panel temperatures. I've tried. What do you do exactly?

The only reason I've ever seen a panel fail for is a blown diode. This is what that looks like. The section is hotter because the diode causes that cell group to short into itself. I don't think you can use a IR thermometer... the difference is too subtle. You need an image.

Screen Shot 2021-06-20 at 12.27.34 AM.png
 
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In your tesla solar account, you have a document titled "customer layout" that you e-signed that says exactly what you're getting. Did they update this document for the delta inverter and have you sign it? If not, then I wouldn't pay them until they install what they sold you.
hi sorka. I have the customer layout saved, it shows SE inverter. I re-downloaded it just now from my account, half expecting to see it mysteriously changed. It hasnt. I havent agreed to (verbally or esigned) anything since late 2020 (when it was suppsoedly SE). The gory details are in posts above, but short of it is Tesla installed on 2/19/21 with a different (*delta) inverter, then "covertly" sent updated plans a few days later to my city inspectors office for approval (changing SE to delta and removing the 36xP400 optimizers; and without telling me, i learned it from the city). I suppose tesla figured i wouldn't notice. I did notice the day of install, asked the installer about it at end of install day as i was walking through checking (("whats this inverter brand?" ... "its a delta, its the same thing. we done?" um, no, why is it changed?.. etc etc."), which started an annoyingly long chain of complaint attempts to tesla for near 4 mos now. I refused the inspector when he showed up later too. Tesla have been telling me its not possible to get SE inverters now, by the way. (Dont think I believe them about that part at this point).
 
Part of the sleight of hand re the agreement, layout, and inverter change is that the purchase agreement and layout are separate documents. They try to be generic in the agreement, which they try to get you to sign before knowing what theyll actually do. I didnt sign that agreement first. i wanted a plan first (and got it and the less detailed "layout").
Interestingly the inverter hardware is listed in the agreement as about $3400 but included "and balance of system" next to it, so i guess they can say they didnt really charge me $3400 for a delta (pretty sure delta inverter is less than half that price even for retail). I dont really see what "balance of the system" would be here, as panels, gateway, powerwalls, mounting hardware, installation, permitting, fees, are all separate line items from it. Retail on the SE 10000 with 36 P400 is about $5000, so i suspect this $3400 line item is in line with what they can get that hardware for.
 
My system went through 2 revisions that required submitting plan revisions to my county. My county wouldn't have accepted them had I not signed off on them. Tesla made me sign each one.
My city accepts and approves plans from tesla /without/ my agreement unfortunately. City did notify me when a new plan was submitted (I have an account with them). When the inspector came (tesla arranged that) and i explained to him what happened, he marked it "not ready." So its still dangling.
 
Had to reply to this as I have had exactly the same experience. I had my 12.2kW system installed by Tesla in Feb 21, where they installed the Delta M10 inverter when my approved plans showed the Solar Edge setup. It has had the same struggling production issues and never been able to generate more than 7.6kW at a time.

I have contacted Tesla multiple times to get resolution and have been ignored just the same. Asked about the deviation from the approved plans and had had no answer. They have also told me everything is working perfectly and I should expect peak output of 60-70% of the rated array size.

I have also logged into the M Professional tool and found multiple "Inverter Over Current (HW) faults.

I'm going to re engage them this week. I am beyond frustrated.

Please keep us posted on if you get to a resolution. I'll do the same.

Thanks, Eric
 
I have contacted Tesla multiple times to get resolution and have been ignored just the same. Asked about the deviation from the approved plans and had had no answer. They have also told me everything is working perfectly and I should expect peak output of 60-70% of the rated array size.

Based on what? Panel orientation? Are the all facing north with lots of shading?

Mid spring I was hitting 7.8 kW every on my 8.16 kW system which was maximum for my inverter. There were a few days with obvious clipping for a 30 minutes or so but most of the time it was knocking the door at the maximum inverter output. In the middle of the summer with 100F+ temps every day, I'm maxing out at 6.4 to 6.5 kW which is about 80% of max rated if you compare max as DC to what I'm actually getting in AC.
 
Based on what? Panel orientation? Are the all facing north with lots of shading?

Mid spring I was hitting 7.8 kW every on my 8.16 kW system which was maximum for my inverter. There were a few days with obvious clipping for a 30 minutes or so but most of the time it was knocking the door at the maximum inverter output. In the middle of the summer with 100F+ temps every day, I'm maxing out at 6.4 to 6.5 kW which is about 80% of max rated if you compare max as DC to what I'm actually getting in AC.
This is the reply their support technician sent me following my repeated inquires.

"Greetings,

Thank you for contacting Tesla. Your system is healthy and producing as expected. Currently, there are no issues or alerts showing via remote access system review. Now, let me explain peak production for solar.

The difference between the system size and the peak production is a very common question. For additional information you may search Google as some websites show testing of most modules to show the manufacturer rating versus testing to show the difference. Overall, the approximate peak level is 60-70% of your actual system size. This is something the sales agent should have explained .The peak output or the size of system is designed under Standard Operating Conditions (Laboratory conditions) and the system may never peak at that value depending on the location, orientation of panels, season, weather, temperature, shade, soiling (all of these real time conditions affect solar performance).

For example a 5.1 kW system would produce a peak level of no more than 3.5 kW. If you have any other concerns, please call Customer Support at 888-765-2489.

Please keep in mind you should receive your gateway 6/18/2021. This will allow us to receive consistent readings on your system.

Regards,"

My system is a flat roof with all panels oriented in the same direction. No significant shading issues (minor chimney shading in the morning).

Image below is my I stalled system.
PXL_20210219_220405018.jpg
PXL_20210219_220401254.jpg


Similar results to others showing significant drop outs during the day, where you can see the entire string shutting down. Also posted one of my best days that seem to show the peak output of the system as only ~7.5kW. it also seems to have distinct shutdowns of an entire string which kills half of the production at a time.
Screenshot_20210706-201815.png
Screenshot_20210706-201712.png

I assume this isn't working properly, but Tesla insisted this was normal.

Last but not least is the error log from the M Professional tool with multiple over current errors.

Screenshot_20210706-202314.png


Any ideas on if this is normal operation? I would have expected much more than the peak of 7.5kW that this has averaged on the best days over the last month and a half. Is there more data I can gather to present to Tesla to have them troubleshoot?

At this rate they are on track to an annual production of ~ 14,000kWh, but my contract estimated 20,692kWh per year.

Eric
 
nocashvalue,
OK, I ran some numbers on your system assuming a 5 degree tilt and location Phoenix. The flat roof is atypical and so your solar production will be somewhat different in character compared to most of us. For your installation, the assertion of 60-70% in the email is sorta, kinda correct, as you'll see in the following. In summer, when the panels are losing 0.36%/C, their output will be down by perhaps 7% relative to standard 25C conditions, where the 12.2kW rating is taken. Maybe the loss is greater than 7%; I don't know the effect of a flat roof on air cooling of the panels. When the panels are freshly installed and clean, you should expect close to 95% base efficiency, but after they've accumulated some dust it may be closer to 92% at 25C. So in June/July when the panels are probably at 40C or more, the expected total efficiency is around 85% or so. The peak insolation taking into account the maximum solar elevation of 79 degrees is about 990W/m^2 in Phoenix.

Multiplying this all together, the system should produce at solar noon about 10.2kW. So the good news is that the Delta M10 inverter is big enough, and will almost never significantly clip. Note that many of us will see max power in March/April and September/October when the air is cooler and the sky is clearer. Your flat roof works against you and as the solar elevation dips lower, the solar panels will drop in power output much more than folks with, say, a 30 degree roof pitch. Near December 21, the expected peak output for your installation, even assuming pretty cold temperatures, won't be above 7kW.

So expected power output is variable from 57% to 84% of nameplate rating (just an estimate of course). But your system is clearly not producing as expected.

The email response from Tesla is, I think, typical and is mostly just taken from a template. I wrote in post #30 in this thread how I would go about getting them to recognize that it is not performing correctly. The key is reaching someone sufficiently technical to understand that 7.6kW peak power in AZ at this time of year is abnormal. If you can show the jaggy performance of your first screen shot when the sky is for sure not subject to occasional clouds, that's also good. Email them pictures (I don't think they can see the string current and voltage from the inverter), but again the sufficiently technical person needs to see the pictures, and I ended up getting the email address of the technical person so that they had access to the pictures.
 
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nocashvalue,
OK, I ran some numbers on your system assuming a 5 degree tilt and location Phoenix. The flat roof is atypical and so your solar production will be somewhat different in character compared to most of us. For your installation, the assertion of 60-70% in the email is sorta, kinda correct, as you'll see in the following. In summer, when the panels are losing 0.36%/C, their output will be down by perhaps 7% relative to standard 25C conditions, where the 12.2kW rating is taken. Maybe the loss is greater than 7%; I don't know the effect of a flat roof on air cooling of the panels. When the panels are freshly installed and clean, you should expect close to 95% base efficiency, but after they've accumulated some dust it may be closer to 92% at 25C. So in June/July when the panels are probably at 40C or more, the expected total efficiency is around 85% or so. The peak insolation taking into account the maximum solar elevation of 79 degrees is about 990W/m^2 in Phoenix.

Multiplying this all together, the system should produce at solar noon about 10.2kW. So the good news is that the Delta M10 inverter is big enough, and will almost never significantly clip. Note that many of us will see max power in March/April and September/October when the air is cooler and the sky is clearer. Your flat roof works against you and as the solar elevation dips lower, the solar panels will drop in power output much more than folks with, say, a 30 degree roof pitch. Near December 21, the expected peak output for your installation, even assuming pretty cold temperatures, won't be above 7kW.

So expected power output is variable from 57% to 84% of nameplate rating (just an estimate of course). But your system is clearly not producing as expected.

The email response from Tesla is, I think, typical and is mostly just taken from a template. I wrote in post #30 in this thread how I would go about getting them to recognize that it is not performing correctly. The key is reaching someone sufficiently technical to understand that 7.6kW peak power in AZ at this time of year is abnormal. If you can show the jaggy performance of your first screen shot when the sky is for sure not subject to occasional clouds, that's also good. Email them pictures (I don't think they can see the string current and voltage from the inverter), but again the sufficiently technical person needs to see the pictures, and I ended up getting the email address of the technical person so that they had access to the pictures.

5 degrees better than 20 degrees for June. 20 degrees nets 2095 kwh for this system in Phoenix in June on pvwatts which takes into account weather and temperature.

5 degrees nets 2214 kwh.

Also, these panels are far off the roof with a roof that is going to cool because it is so light.

Tesla can't tell you the system is functioning normally if the inverter keeps cutting off and you have the graphs to prove it. That's what you need to focus on.

Also, this installation is ideal for adjustable tilt rack mounts. The arrays are far apart so you can tilt them to the optimal tilt for the season. You could even install motorized fixed azimuth adjustable longitude mounts that can adjust the angle throughout the day netting you about 30% more total production.
 
This is the reply their support technician sent me following my repeated inquires.

"Greetings,

Thank you for contacting Tesla. Your system is healthy and producing as expected. Currently, there are no issues or alerts showing via remote access system review. Now, let me explain peak production for solar.

The difference between the system size and the peak production is a very common question. For additional information you may search Google as some websites show testing of most modules to show the manufacturer rating versus testing to show the difference. Overall, the approximate peak level is 60-70% of your actual system size. This is something the sales agent should have explained .The peak output or the size of system is designed under Standard Operating Conditions (Laboratory conditions) and the system may never peak at that value depending on the location, orientation of panels, season, weather, temperature, shade, soiling (all of these real time conditions affect solar performance).

For example a 5.1 kW system would produce a peak level of no more than 3.5 kW. If you have any other concerns, please call Customer Support at 888-765-2489.

Please keep in mind you should receive your gateway 6/18/2021. This will allow us to receive consistent readings on your system.

Regards,"

My system is a flat roof with all panels oriented in the same direction. No significant shading issues (minor chimney shading in the morning).

Image below is my I stalled system.
View attachment 682138View attachment 682139

Similar results to others showing significant drop outs during the day, where you can see the entire string shutting down. Also posted one of my best days that seem to show the peak output of the system as only ~7.5kW. it also seems to have distinct shutdowns of an entire string which kills half of the production at a time.
View attachment 682140View attachment 682141
I assume this isn't working properly, but Tesla insisted this was normal.

Last but not least is the error log from the M Professional tool with multiple over current errors.

View attachment 682142

Any ideas on if this is normal operation? I would have expected much more than the peak of 7.5kW that this has averaged on the best days over the last month and a half. Is there more data I can gather to present to Tesla to have them troubleshoot?

At this rate they are on track to an annual production of ~ 14,000kWh, but my contract estimated 20,692kWh per year.

Eric
My graph has never looked as good as that June 6th you posted, nor have I ever hit a total kwh daily that is that high. The "yesterday" graph is more like most of my days. It looks like your array is not putting out as much as mine, but it's angled lower too. Mine is at the roof angle which is a bit under 20deg. I think for yours I would consider raising the angle up, as it looks like it's pointed too high, assuming it's roughly southish. I bet the June 6 graph is good. It's smooth, the clip point looks a bit low, but the smoothness up to that clip point suggests no issues on that day with the inverter dropping out, and how narrow/small the clip at the top is suggests it was near the max string output(but see below) . What was the sky like on these 2 days? Your error log has far fewer problems than mine shows, which is arc fault error about every day. Maybe you have a lot less shading than I do.
I am curious, what Inverter firmware version(s) does your m10 currently show in the m prof app? On the date of "yesterday" What do the voltage graphs look Like for pv1 and pv2? Do they bounce between about 10 volts and 400 but nothing between? That's what mine does, when there is any disturbance like a wispy cloud, or when the shade starts touching it.
How many panels are on each of your strings? And what do the amp outputs of pv1 and pv2 in m prof look like? Weird string sizes might explain Why you get clipping at only 7.8.
Overall I am betting tipping your panels up would gain you something. It looks like you have that option there. Then figure out why you have that choppy output day(s). If that hardly ever happens, then maybe you just need to tip your panels toward sun angle more.
 
My system is a flat roof with all panels oriented in the same direction. No significant shading issues (minor chimney shading in the morning).

Image below is my I stalled system.
View attachment 682138
in that top image your panels look like they are pointed pretty high, even for summer.
try a solar angle calculator, heres one link: Solar Angle Calculator
put in your location to the calculator to get the angles. I think you would want to put your panels closer to the spring/fall angle if you dont want winter output to suffer badly.
 
@dareed1 and @nwdiver

Here is my attempt to get yesterday’s (6/15) history of volt/amp graphs out of my delta M10-TL-US with one of versions of delta's mobile app (Mtool itself on the apple store or android was hardly helpful, i was able to find via a archive site mtool prof (M professional). and how to activate it (act code dareed gave actually). Firmware version seems to be 2.2.13.
The set of graphs are: volts/amps for one 24 hr window (06/15) PV1, PV2, (and PV3 :?)
PV1 (volt, amp, 24 hour window, dies off when the left 12 panels get shaded, so probaly tied to those)
View attachment 674265View attachment 674264
PV2 (maybe the MPPT with 2 strings tied to it? amperages are near double PV1, and its output drops at the time the right 24 panels in upper pisture start seeing shade. )
View attachment 674266View attachment 674267
PV3 ??? RE PV3: maybe just the firmware or software has the variables in it but no terminals to it. The app thinks there are 3x PV, or at least some layers of the software/firmware do. My "checkup" installer was pretty sure there was nothing in there to hook a third input up to, and it looked that way to me when we were poking around in there together ( i was an electronics tech for a number of years an age ago, so i am not totally new to this stuff, just new to solar.)
View attachment 674268View attachment 674269

NOTE the error log top page, I am not familiar with what "arc faults" mean in solar-speak, but sounds suspiciously like some wire, connector, or panel is loose and voltage is arcing across a gap. Please correct me if that is not the right idea. Looseness could be INSIDE the inverter too I guess, even bad solder joint, faulty circuitry. How would the firmware be trying to detect that? Maybe voltage drops faster than a threshold? Or maybe its just crappy firmware?
View attachment 674270

IN NEXT POST: AC active power, reactive pwr, current, freq, volts; plus the tesla apps Solar CT leg info for the same time window.
Hello @Heretic. I have also used the M Professional tool (iOS), but I have never been able to get it to display the historical Pv graphs like these. It draws the graph box/grid for each Pv, but doesn’t draw the graph lines. Do you have any thoughts on how I can get it to work? Otherwise M Prof seems to work fine for me.
 
Hi folks, sorry to drag this from the depths of yesteryear, but I'm curious if anyone has gotten sufficient resolution yet?

I also have a Delta M10-TL-US, also sprung on me what it was supposed to be SolarEdge. I never made over 8700 watts. And have Arc Fault Self Test Failure showing up in the log multiple times a day.

I gave up on Tesla support, threw my warranty in the bin, and installed Tigo optimizers and added another inverter myself, and now I make all the power I expect, but I still see the arc fault self test failures...
I finally reached out to Delta solar support directly, but they told me they can't do anything without a case being opened by Tesla. Based on my description they agreed there was a problem with the inverter, but Tesla won't ever do anything for it.
 
Hi folks, sorry to drag this from the depths of yesteryear, but I'm curious if anyone has gotten sufficient resolution yet?

I also have a Delta M10-TL-US, also sprung on me what it was supposed to be SolarEdge. I never made over 8700 watts. And have Arc Fault Self Test Failure showing up in the log multiple times a day.

I gave up on Tesla support, threw my warranty in the bin, and installed Tigo optimizers and added another inverter myself, and now I make all the power I expect, but I still see the arc fault self test failures...
I finally reached out to Delta solar support directly, but they told me they can't do anything without a case being opened by Tesla. Based on my description they agreed there was a problem with the inverter, but Tesla won't ever do anything for it.
This is just seems illegal to me, but at least poor customer support. Contrast this with Fronius, which I have two of installed by two different organizations. When I call Fronius for support (have 3 times) they treat me with respect and are very accommodating. And their support is great and helpful too, mixing direct phone calls, call backs and same day emails.

The one time I did have a Delta issue I had to prove to Tesla there was a problem by hacking the inverter UI and taking pictures. They did fix it fairly quickly with a FW update, but still ...