Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Delta M-4, String drops out to zero for 2 hrs ? [delta inverter issues]

This site may earn commission on affiliate links.
I dropped today between 11-11:15. Same time?

I called in yesterday. About a 10min wait, he said he would send it to diagnostics team. A week typically for them to respond.

Do you see overcurrent errors in your error log?
 

Attachments

  • Screenshot_20210408-145516_Tesla.jpg
    Screenshot_20210408-145516_Tesla.jpg
    72.1 KB · Views: 57
No official word from their support team as of today (+8 days from original contact). Meanwhile, I'm losing out on ~2kW of production during the sunniest portion (from 11AM to 4PM) of a very sunny past two days. That works out to about 10kWh of lost production per day. Not happy.

1617998133688.png

1617998162888.png
 
8 days and still nothing from Tesla. I hope to hear from them soon.
I read these with interest. So much bashing of solaredge. But, I have had a few issues, and lots of questions. SE technical support has been nothing but amazing! Always call back within an hour or two. Every issue has been dealing with in real time. Sure glad I did not go with a tesla inverter
 
I read these with interest. So much bashing of solaredge. But, I have had a few issues, and lots of questions. SE technical support has been nothing but amazing! Always call back within an hour or two. Every issue has been dealing with in real time. Sure glad I did not go with a tesla inverter

Congratulations? Not sure what that adds to the conversation... No one here is talking about a Tesla inverter.
 
I emailed the CS agent I'd been in contact with by replying, and received the following:

Thank you for your email. The process typically only takes a few days though I think, in this case, they are being more thorough to make sure all the proper steps have been and are being taken.

According to the most recent notes, they have updated the firmware on the inverter, and will continue to monitor the inverter's performance to help determine how much of the production is due to actual inverter issues versus Colorado weather patterns. The Systems Diagnostic team will continue to monitor and reassess the week of 04/19 to determine the next steps. I will follow up with you at that time.

I'm doubting the firmware update did anything (unless they did it in the past day or so), since I last noticed the string shunting (or whatever you want to call it) at midday on 4/9, which was our last day of full sun:

1618511586197.png

1618511607913.png
 
On perfectly clear blue-sky no shadow days our solar roof Delta M8 inverter persistently faults with "Inverter Over Current(HW)" messages in the history log of the M Professional App, the same app the Tesla installer used to comm with the inverter at final inspection.

This leads to the very spikey no power/ max power graphs depicted in many other threads, the inverter sounds like a drum machine as it faults then resets every 60-90 seconds, household lights persistently flickering or pulsing, inverter circuitry resonating in a pulsing fashion, and suboptimal system energy production since it's in persistent oscillation between no or max power for a good portion of the day.

System = 9.4kW peak capable solar roof separated into 3 strings, Delta M8 single phase inverter. PTO 01FEB2021.

Tesla first line support offered no answers, other than to "escalate" by scheduling an onsite service call 1 month from today. Gee thanks.

So i called Delta directly. They asked for the historical maximum current recorded for each of the 3 strings. In our case 12.5A for each, and peaking at that often 10:00-14:00 for several days this month as the sun rides higher in the sky.

The Delta8 spec sheet clearly specifies "Maximum input current (per MPPT) - 12A". So Delta concluded this is a system design issue such that each string is frequently supplying current over the inverter max spec per string.

Anyone else having similar issues? Would you agree the system design likely undersized the inverter?
 
On perfectly clear blue-sky no shadow days our solar roof Delta M8 inverter persistently faults with "Inverter Over Current(HW)" messages in the history log of the M Professional App, the same app the Tesla installer used to comm with the inverter at final inspection.

This leads to the very spikey no power/ max power graphs depicted in many other threads, the inverter sounds like a drum machine as it faults then resets every 60-90 seconds, household lights persistently flickering or pulsing, inverter circuitry resonating in a pulsing fashion, and suboptimal system energy production since it's in persistent oscillation between no or max power for a good portion of the day.

System = 9.4kW peak capable solar roof separated into 3 strings, Delta M8 single phase inverter. PTO 01FEB2021.

Tesla first line support offered no answers, other than to "escalate" by scheduling an onsite service call 1 month from today. Gee thanks.

So i called Delta directly. They asked for the historical maximum current recorded for each of the 3 strings. In our case 12.5A for each, and peaking at that often 10:00-14:00 for several days this month as the sun rides higher in the sky.

The Delta8 spec sheet clearly specifies "Maximum input current (per MPPT) - 12A". So Delta concluded this is a system design issue such that each string is frequently supplying current over the inverter max spec per string.

Anyone else having similar issues? Would you agree the system design likely undersized the inverter?

It's fine. I have 10.7kW on a 8kW inverter.

Array Oversizing
 
i did. you oversimplify and clearly didn't read our situation. oh well ... here goes more flippant sound bites from "experts".

You have a problem but an undersized inverter isn't it. Solar arrays don't 'push' power into the inverter, the inverter harvests the energy. If 20A is available on a MPP channel but the inverter can only take 12.5A it's only going to take 12.5A.
 
  • Informative
Reactions: MorrisonHiker
On perfectly clear blue-sky no shadow days our solar roof Delta M8 inverter persistently faults with "Inverter Over Current(HW)" messages in the history log of the M Professional App, the same app the Tesla installer used to comm with the inverter at final inspection.

This leads to the very spikey no power/ max power graphs depicted in many other threads, the inverter sounds like a drum machine as it faults then resets every 60-90 seconds, household lights persistently flickering or pulsing, inverter circuitry resonating in a pulsing fashion, and suboptimal system energy production since it's in persistent oscillation between no or max power for a good portion of the day.

System = 9.4kW peak capable solar roof separated into 3 strings, Delta M8 single phase inverter. PTO 01FEB2021.

Tesla first line support offered no answers, other than to "escalate" by scheduling an onsite service call 1 month from today. Gee thanks.

So i called Delta directly. They asked for the historical maximum current recorded for each of the 3 strings. In our case 12.5A for each, and peaking at that often 10:00-14:00 for several days this month as the sun rides higher in the sky.

The Delta8 spec sheet clearly specifies "Maximum input current (per MPPT) - 12A". So Delta concluded this is a system design issue such that each string is frequently supplying current over the inverter max spec per string.

Anyone else having similar issues? Would you agree the system design likely undersized the inverter?

(moderator note: moved the thread you created into this one, which describes issues some people are having with delta inverters)
 
  • Like
Reactions: nwdiver
You have a problem but an undersized inverter isn't it. Solar arrays don't 'push' power into the inverter, the inverter harvests the energy. If 20A is available on a MPP channel but the inverter can only take 12.5A it's only going to take 12.5A.
ok. so you have a system designed by Tesla/Solar City where 3 PV strings output greater than 12A per string persistently for up to 4hrs recently (to be precise 12.5A), and an 8kW inverter that accepts no more than 12A per input string and persitently faults and resets in an oscillatory fashion when >12A (as designed for safety purposes), and very little power gets produced. Hmmm ... please enlighten me further thanks.
 
ok. so you have a system designed by Tesla/Solar City where 3 PV strings output greater than 12A per string persistently for up to 4hrs recently (to be precise 12.5A), and an 8kW inverter that accepts no more than 12A per input string and persitently faults and resets in an oscillatory fashion when >12A (as designed for safety purposes), and very little power gets produced. Hmmm ... please enlighten me further thanks.

No... but I understand how PV systems operate. The current output of a solar panel is based on insolation of 1000w/m^2 but that number can easily be exceeded by something called 'cloud edge effect' so if the inverter allowed the PV array to push current it would trip on a partly cloudy day everytime there's a break in the clouds. Inverters are designed with this in mind. The critical threshold isn't the max DC input the inverter can use (12A) .... but the max DC input it can handle under a fault condition. Which is 15A in your case. But that's only if there's a fault. You could have 4MW of panels connected to the inverter and it's only going to take 12A. The 15A is just to make sure the inverter doesn't vanish in a puff of blue smoke if there's a short...

Bottom line is the only way too many panels can CAUSE a problem is if they exceed 600v. A good analogy would be a dam. You can't damage a dam by increasing the area or volume of the reservoir. Only by increasing the height. The height of the reservoir is analogous to the voltage of the PV system.

Screen Shot 2021-04-20 at 3.25.36 PM.png
 
Last edited: