62.8 Hz at 92%?????

[sorka]

A week ago I tested my powerwalls off grid and let my solar charge them all the way up to 98% before the frequency went to 60.4 Hz and the inverter shut off. It cycled a few times as the battery drained to low 98% and the frequency went down to 60.1 or 60.2 and the inverter would come on again. This repeated several times.

I did this test to see what would happen with my extensive Insteon lighting system. Out of some 200 devices, only 2 didn't respond to an ALL query at this frequncy.

Well today, I decided to burn some power off my 92% charge because I didn't want it just sitting there at that state all day long until peak hit and I was just itching to test backup mode again, so I turned the main breaker off.

All my lights inside instantly started flickering. I took a glance at the Kill-A-Watt to se 62.8 Hz. WTF????? Why did it the frequency go so high at only 92%????

Killed two of my Insteon switches. They're dead and won't even turn on locally by hand. Even though all my network equipment is on a giant UPS and it switched over to the UPS, all my Unify equipment had to be rebooted to restore all my wifi APs to working order. Basically the frequency wrecked havoc with all of my sensitive equipment.

The only difference that I know if is that my power walls just updated from 1.50.1 to 1.50.2

 

[RKCRLR]

I've been having problems with my solar operation when the grid is down. My solar works fine if the grid is up. I had a power outage last Friday for a couple of hours. The SoC was down to 91% and the solar still wasn't on the last time I checked the app. When I looked at the history the solar didn't start charging again until the grid was back up. I have both an old string system and a rule 21 compliant (Enphase) system. It seems like it should have been operating at 91% SoC.

 

[BrettS]

That definitely seems odd and is certainly different than anything I saw during my off grid testing. However as far as I know Tesla doesn’t really publish any details about exactly how this works, so all that we know is just based on observation of how our systems behave.

I certainly can’t think of any reason for your system to increase the frequency at 92%

 

[tommax]

I'm seeing something sort of similar.

Details: Pre-PTO, two PW2, Solaredge SE3800H (no display).

This is what is happening:

1) Disconnect grid at TEG
2) Turn on inverter
3) Frequency at 59.6-59.7
4) Solar starts to be produced
5) Within seconds, frequency goes to 60.3-60.4
6) Inverter turns off
7) Cycle repeats every 5 or 10 minutes.

I've reset TEG and inverter multiple times.

At times solar will produce for an hour, then frequency increases. On other days, no solar production for an hour, then it works for 45 minutes, then the frequency keeps increasing, turning the inverter on and off again.

 

[sorka]

I'm seeing something sort of similar.

Details: Pre-PTO, two PW2, Solaredge SE3800H (no display).

This is what is happening:

1) Disconnect grid at TEG
2) Turn on inverter
3) Frequency at 59.6-59.7
4) Solar starts to be produced
5) Within seconds, frequency goes to 60.3-60.4
6) Inverter turns off
7) Cycle repeats every 5 or 10 minutes.

I've reset TEG and inverter multiple times.

At times solar will produce for an hour, then frequency increases. On other days, no solar production for an hour, then it works for 45 minutes, then the frequency keeps increasing, turning the inverter on and off again.

What was the charge level of your batteries?

 

[tommax]

What was the charge level of your batteries?

It doesn't seem to matter very much. One time the frequency increases started at 80%. I gave up and tried another day and it went to 86%. The next day it got to 92%. Today it went to 90%.

 

[jeep1979]

In my experience there are a couple of conditions that Tesla will shut down solar even if the batteries should be charging.

The first that seems more likely is that the solar produces more charge than the batteries can take. In my case my two batteries can receive about a maximum of 6.7 kw. So, if the solar is producing a higher amount and the grid is down, there is nowhere for the excess electricity production to go, so Tesla will shut down the solar production.

The other which I have experienced because my batteries are mounted outside is extreme cold. As the temperature approaches freezing and the grid is down, Tesla will also shutdown solar because of the cold, the batteries can only accept a very reduced charging rate. This may have been fixed in last April's software update. Until then, prewarming the batteries only occurred if the grid was up. The April software update may have changed that to include prewarming the batteries even if the grid was down. I have not been able to confirm this yet.

 

[sorka]

I have three poweralls and the temp was about 70F. The batteries were taking the full solar charge minus house usage when I went off grid. My solar output at the time was about 4 KW (partly cloudy all day yesterday). Even at maximum they don't come anywhere near close to exceeding the powerwall charge limit. The powerwalls continued to output 62.8 Hz even with the solar off until I restored the grid.

 

[RKCRLR]

I have a 4kW string system and a 6kW Panasonic/Enphase system that can be modulated, and 2 powerwalls. Friday's outage was on a partially cloudy day. The solar output prior to the outage was 5kW and 2.3kW once the outage was over. The temperature was about 50F (and the powerwalls are inside my shop). The outage lasted about an hour and a half and the solar was never commanded on the whole time. The powerwall charge level was down to 91% the last time I checked during the outage (I don't know how to check the charge level history to see the lowest point).

 

[sorka]

Testing again today. Disconnected grid this morning with 25% left after solar was passed the 2KW production mark. Minus what the house consumed, it's taken all day to charge back up to 91% with about an hour of sun left. Frequency if fluctuating between 60 and 60.1 Hz up from 59.7 to 59.9 throughout the day.

 

[sorka]

Drat. Not an hour of sunlight left after all. Don't think I'm going to even hit 92%.

 

[RKCRLR]

When I called Tesla they said it is normal to get down to 90% before commanding the solar back on. They said there is no fixed point. Seems strange.

 

[sorka]

When I called Tesla they said it is normal to get down to 90% before commanding the solar back on. They said there is no fixed point. Seems strange.

I'm fine with that as long as it doesn't go over 60.4 Hz.

 

[RKCRLR]

I'm fine with that as long as it doesn't go over 60.4 Hz.

Keeping the frequency above 60.4 Hz is how they keep the solar inverters from producing. Some have managed to have Tesla lower the maximum frequency from 65 Hz to something lower (62.5 Hz I think) but not as low as 60.4 Hz (that wouldn't work).

 

[sorka]

Keeping the frequency above 60.4 Hz is how they keep the solar inverters from producing. Some have managed to have Tesla lower the maximum frequency from 65 Hz to something lower (62.5 Hz I think) but not as low as 60.4 Hz (that wouldn't work).

That's how mine used to work. It would climb up to 60.4 Hz at 98% and the inverter would shut off.
Most of the things in my house won't run on 62.5 Hz and even destroyed Insteon switches. My replacements come today. That was with about 2 minutes of exposure with every light in the house randomly flickering on and off. I have no doubt had I let it go on or if this happened while I was away from home and couldn't kill power that the damage would have been far more severe.

 

[RKCRLR]

There is a long thread in this forum about the frequency issue, mainly related to UPS backups.
Utilities plan to use frequency shifting some time in the future to control solar production.

 

[BrettS]

There are two different scenarios where the frequency might be raised and the frequency that it winds up at is different in each scenario. Also, keep in mind that the only time the frequency can be changed is when there is an outage. So what I am discussing below assumes that the power is out.

In one scenario the powerwalls start at a lower SOC and as they approach 100% the frequency will slowly start to raise. It will go from 60.0 to 60.1 to 60.2, etc. When it gets to 6.5 the inverters will shut off and the powerwalls will power the house, so their SOC will lower again. In this case the frequency will never get above 60.5 because the inverters will shut off at that point.

In the second scenario the power fails while the powerwalls are at a high SOC. In this case the frequency doesn’t slowly raise, but instead will immediately jump to whatever is set as the max frequency. (65 by default or maybe 63 or 62.5 if tesla has lowered it).

In my experience these frequency changes all happened at a SOC of 98% or higher, so I still don’t know why you are seeing any frequency changes at 92%. But there are cases where the frequency will stay at or under 60.5, no matter what the max frequency is set to as well as cases where the frequency will go all the way up to the max.

 

[wjgjr]

There are two different scenarios where the frequency might be raised and the frequency that it winds up at is different in each scenario. Also, keep in mind that the only time the frequency can be changed is when there is an outage. So what I am discussing below assumes that the power is out.

In one scenario the powerwalls start at a lower SOC and as they approach 100% the frequency will slowly start to raise. It will go from 60.0 to 60.1 to 60.2, etc. When it gets to 6.5 the inverters will shut off and the powerwalls will power the house, so their SOC will lower again. In this case the frequency will never get above 60.5 because the inverters will shut off at that point.

In the second scenario the power fails while the powerwalls are at a high SOC. In this case the frequency doesn’t slowly raise, but instead will immediately jump to whatever is set as the max frequency. (65 by default or maybe 63 or 62.5 if tesla has lowered it).

In my experience these frequency changes all happened at a SOC of 98% or higher, so I still don’t know why you are seeing any frequency changes at 92%. But there are cases where the frequency will stay at or under 60.5, no matter what the max frequency is set to as well as cases where the frequency will go all the way up to the max.

In my experience (with a Delta inverter, so I know that may change things) when the powerwalls are at a lower charge and then approach full, the frequency does not stop at 60.5 - it continues to rise towards 65 Hz. It does not necessarily get that high (even if you did not request Tesla to lower it) but I saw numbers in the 63 Hz range. So, I would definitely advise any new installs to test and see the behavior. (Of course, I should probably test again some time given that some are now reporting the solar being shut down in the low 90s for the PW charge, rather than the 98% that I also found in my testing.)

 

[sorka]

There is a long thread in this forum about the frequency issue, mainly related to UPS backups.
Utilities plan to use frequency shifting some time in the future to control solar production.

Yea, none of the 3 UPSs I have stay connected to AC when the frequency is that high which means everything on them including my extensive Ubiquiti Unifi system and all of my home automation controllers, ISY, RPIs, etc all will shut down after the UPS runs out.

 

[sorka]

Disconnected grid at 82% today. Output went to 60.6 Hz and solar shut off so I'm on battery only and draining at 82% and falling.