Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register
  • We just completed a significant update, but we still have some fixes and adjustments to make. Please see this thread for more details and to find out how to revert to the old design. Cheers!

No generation in the morning till about 10am. Error 18x86: Isolation

Cherd

Member
Feb 25, 2020
6
1
San Jose
I noticed an odd behavior with my power system recently. In the past 1 week, 5 out of 7 days, there was no generation in the morning till 15-30 minutes before 10am. The graph short sudden start of generation right from 5kW or so. But 2 of those days, they work normally gradually increased from 0. The weather has been clear for the whole week. I am in San Jose and. Normally generation would start before 8am.

When I look at my Tesla app, similar thing has happened, but less frequently in the month of July.

I have tried restarting the inverter twice earlier in the week and by chance I think the first time generation started shortly after that but both around 9:30am. One of those time while chatting with Tesla support. And they simply said "looks like problem is solved, is there anything else we can help" and wanted to hang up. After I insisted it's not normal, they said they would look into it but today I got an email saying my generation looks normal.

I tried restarting the inverter on a 3rd day earlier in the morning and saw that the MySolarEdge app is telling "P_OK: 35 of 36 Optimizers Communication". That number increased from 1 slowly until it reached 35 and stuck. Also under Error Log it shows "Error 18x86: Isolation".

This morning, without restart the inverter, I logged on to MySolarEdge app and saw the same thing again, 35 of 36, and another Error 18x86: Isolation, and no generation.

While waiting for a call back from Tesla, and writing this, generation started at around 9:35am.

Could this be a bad cable (caused by squirrels, broken solar panels which I have a few by golf balls) or is there anything else I could check?
 

Attachments

  • IMG_2567.png
    IMG_2567.png
    132.5 KB · Views: 11
Upvote 0
By the way, my system has 36 panels with 3 Powerwalls. Installed the Summer of 2020.
I had a similar problem awhile back with isolation errors, it turns out squirrels had eaten away at some of the cable insulation (not the actual wiring) which would allow water to enter, when things were dry everything worked well, but after rains the system would be down. So I had a product called Solartrim installed around the solar array so squirrels couldn't get underneath the panels. No problems since then
20201016_163501976_iOS.jpg
 
Upvote 0

wwhitney

Active Member
Nov 2, 2017
1,018
1,384
Berkeley, CA
So, have you googled "Error 18x86: Isolation"? There are various troubleshooting PDFs. Most of them involve things that only a qualified installer should do, like Tesla, not a homeowner.

This video, the first 5 minutes may be of interest; ignore the rest of it, which has various errors (I didn't watch the whole thing). Also, the presenter misspeaks when he refers to the 50% vs 99.5% as being related to resistance; that is showing that in the correctly working system, the AC side ground potential is half way between the DC + and DC - potential, as it should be for any modern transformerless inverter. Whereas the faulted system shows that the AC side ground potential is close to DC - (i.e the fault is on the DC- lead).


Your newer inverter may not have the physical buttons, but hopefully you could pull up the same diagnostics screen on your Solaredge app (I'm not familiar with the app myself, I have the older style with buttons).

The upshot is that most likely, somewhere in the system one of the DC leads is close to a grounded object (e.g. the array racking), and the insulation separation is marginal, and when it gets wet overnight with dew, you have an isolation fault. Then when it dries out you have the proper isolation and the fault clears.

Cheers, Wayne
 
  • Helpful
Reactions: BGbreeder
Upvote 0

Cherd

Member
Feb 25, 2020
6
1
San Jose
I had a similar problem awhile back with isolation errors, it turns out squirrels had eaten away at some of the cable insulation (not the actual wiring) which would allow water to enter, when things were dry everything worked well, but after rains the system would be down. So I had a product called Solartrim installed around the solar array so squirrels couldn't get underneath the panels. No problems since thenView attachment 694860
Thanks for the Solartrim recommendation. I think I will need it. There's a lot of squirrels going up my roof.
 
  • Like
Reactions: darhall993
Upvote 0

Cherd

Member
Feb 25, 2020
6
1
San Jose
So, have you googled "Error 18x86: Isolation"? There are various troubleshooting PDFs. Most of them involve things that only a qualified installer should do, like Tesla, not a homeowner.

This video, the first 5 minutes may be of interest; ignore the rest of it, which has various errors (I didn't watch the whole thing). Also, the presenter misspeaks when he refers to the 50% vs 99.5% as being related to resistance; that is showing that in the correctly working system, the AC side ground potential is half way between the DC + and DC - potential, as it should be for any modern transformerless inverter. Whereas the faulted system shows that the AC side ground potential is close to DC - (i.e the fault is on the DC- lead).


Your newer inverter may not have the physical buttons, but hopefully you could pull up the same diagnostics screen on your Solaredge app (I'm not familiar with the app myself, I have the older style with buttons).

The upshot is that most likely, somewhere in the system one of the DC leads is close to a grounded object (e.g. the array racking), and the insulation separation is marginal, and when it gets wet overnight with dew, you have an isolation fault. Then when it dries out you have the proper isolation and the fault clears.

Cheers, Wayne
Thanks for sharing the video. Sounds like a very tough to troubleshoot issue unless Tesla come onsite when it is not working. My inverter doesn't have a LCD screen. The MySolarEdge app is readonly, and have very limited information, not as shown in the video. There is another app called SetApp but it says I don't have permission to log on. It worked fine for 3 consecutive days after I posted, but again gave problem yesterday and today. Will have to get hold of Tesla again when during the 1-1.5 hour window when it happens again. I have not been able to someone on Tesla customer support. The wait time has been over 30 minutes, and ended up with call getting dropped. Hopefully I will have better luck next week.
 
Upvote 0

SMAlset

Well-Known Member
Mar 4, 2017
9,251
10,124
SF Bay Area
@Cherd Appreciate the image. We have a late model SE inverter without display screen and if we ever see a graph like that in our Tesla app I will remember your post.

We had metal bird abatement mesh installed at time of our solar array install, as even Tesla’s Q-Cell panel skirts leave some room underneath and the back roof ridge side is not skirted at all so fully open. Definitely want to keep ventilation for the panels just not provide access for the animals. Definitely good for birds, squirrels or roof rats that are prevalent in the SF Bay area with all the fruit trees around.
 
Upvote 0

Products we're discussing on TMC...

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


SUPPORT TMC
Top