Strange restarts

[RobbL]

We are in the fire zone in Northern California so our power was turned off as scheduled last night, 10/25. Powerwall took over quickly and all seemed right. I was surprised and disappointed to learn that my Comcast Internet does not work during a power outage despite my cable modem continuing to operate. And unfortunately, because we live in the Oakland Hills, our cell phone connection is weak. I’m using it now through Bluetooth, but it is slow.

in any case, I was satisfied overall, the battery went down to around 50% and started recharging this morning through solar, and is now back to 100%. So everything else worked as planned. However, around Noon and then twice again in the next hour, the power went off and immediately came back on. I don’t think this was PGE. My Comcast Internet connection never came back and there was no change in the schedule of power from PGE not being restored until tonight. So why did the power recycle? Should I call Tesla? Did this happen to anyone else?

 

[BrettS]

When you say the power went off and immediately came back on exactly what do you mean? The lights and such in your house went out and then came back on? How quickly was immediately? Was it just a flicker or were they off for a few seconds?

You certainly shouldn’t experience any power flickering or fluctuation or anything while the powerwalls are powering your house. What do your power graphs in the Tesla app look like during that time period?

 

[RobbL]

When you say the power went off and immediately came back on exactly what do you mean? The lights and such in your house went out and then came back on? How quickly was immediately? Was it just a flicker or were they off for a few seconds?

You certainly shouldn’t experience any power flickering or fluctuation or anything while the powerwalls are powering your house. What do your power graphs in the Tesla app look like during that time period?

The power to the house went off completely and immediately came back on. My old laser printer makes a noise when it restarts and I heard that noise each time. The powerwall graph and the solar graph both show several very close increase and decrease around that time.

 

[jjrandorin]

We are in the fire zone in Northern California so our power was turned off as scheduled last night, 10/25. Powerwall took over quickly and all seemed right. I was surprised and disappointed to learn that my Comcast Internet does not work during a power outage despite my cable modem continuing to operate. And unfortunately, because we live in the Oakland Hills, our cell phone connection is weak. I’m using it now through Bluetooth, but it is slow.

in any case, I was satisfied overall, the battery went down to around 50% and started recharging this morning through solar, and is now back to 100%. So everything else worked as planned. However, around Noon and then twice again in the next hour, the power went off and immediately came back on. I don’t think this was PGE. My Comcast Internet connection never came back and there was no change in the schedule of power from PGE not being restored until tonight. So why did the power recycle? Should I call Tesla? Did this happen to anyone else?

Your internet being out (or not) has to do with how widespread the internet outage is. If the depot in your neighborhood has no power, then even though you have power to your modem, the equipment at the depot doesnt so, no internet. It depends on if they (your ISP) has that backed up with a UPS, and if so, how much battery etc.

Just explaining why you might or might not have internet during a power outage.

As to "why did the power cycle" in addition to what @BrettS said, it also could depend on how many powerwalls you have, and what tried to start up during that time. its possible that something tried to start up that needed more power than your powerwall(s) could provide (like some sort of pump, pool heater, AC, Electric oven, etc.

Based on the description, thats what it sounds like to me anyway.. that something tried to start up, and the powerwall couldnt quite provide power for the surge. Just guessing since thats all we can do at this point. There isnt a reason powerwall power itself should drop out while powering your home.

 

[jjrandorin]

The power to the house went off completely and immediately came back on. My old laser printer makes a noise when it restarts and I heard that noise each time. The powerwall graph and the solar graph both show several very close increase and decrease around that time.

Maybe you should check the startup power needs of that old laser printer, for example.

 

[BrettS]

The power to the house went off completely and immediately came back on. My old laser printer makes a noise when it restarts and I heard that noise each time. The powerwall graph and the solar graph both show several very close increase and decrease around that time.

Again, immediately can mean different things to different people. Can you try to quantify what you mean? Was it just a flicker or was the power actually out for a couple of seconds?

@jjrandorin might be into something. I think that if you actually overload the powerwalls they will shut off for safety, but if that’s what happened I feel like they may be off for more than a a few seconds. They may even need to be manually restarted.

But it could still be something with a large startup power demand that might be causing a short sag as it starts up. Was your air conditioner on at the time? It’s possible that when it’s compressor started that might be enough to do it.

 

[boaterva]

If things are working properly the only time you know you are on Powerwall power is by looking at your Tesla app. You shouldn’t have ‘flickering’ or an outage or anything unless you have too high a load for them. And unless you have a ten year old laser printer, that’s not it. We have a home Brother laser printer that has no issues at all.

 

[bob_p]

We haven't seen any power fluctuation when running our TEG when the grid is down. If the OP's system is experiencing brief outages while operating off-grid, the system should be checked.

We have Comcast in the Houston area. When we've had extended outages after hurricanes, we've lost grid power - but our Comcast phone, internet and TV service continued. Comcast evidently has separate power to operate their network (at least in our area) even if the grid power is out.

Sometimes Comcast will install a signal booster to increase the signal strength inside a house. This booster requires power. If Comcast signal is lost during a power outage, it might be worthwhile to look at where the Comcast cable is coming in and check if there's a booster - and where it's being powered (if it's connected to a circuit that's not powered by the TEG).

 

[RKCRLR]

When the grid goes down or comes back I see a split second blink of my LED lights. It isn't enough to cause my clocks to start blinking or anything. When I see that I know to check the power status.

My AC is in the backup and most of the time the Powerwalls can't start it. It is a "smart" system and immediately errors out for a period of time if the power goes down. If the AC tries to start while running off the Powerwalls the power will go of for a second or two but then comes back on.

 

[JPP]

I live in the SF Bay Area in the east bay (east of you). No PSPS for me today but one about 1 mile west (day 2 of 3). I have 2 PWs and 16kW solar 9afterlast year's 2 October events). With Comcast, I lose my internet in a few hours once their local switches and hubs run out of power. Cell service (AT&T) is spotty here and goes down in about 1 day. I lose telephone (Comcast VoIP) and cell, as well as internet. Black hole. Last December I installed HughesNet satellite internet. Bog ugly dish on the roof. Speed about 20 megs down/5 up. Limited data cap. $70/month. I use this as a crash & burn backup for minimal internet and phone. Waiting for Starlink (more $$ but likely faster with a smaller dish).

 

[RobbL]

I don't think the issue was my old laser printer. I believe it only happened three times, and all within about 60 to 90 minutes. I only knew because of the sound the printer makes when it starts up. It was around noon, so no lights were on. I called it in to the company that did the install. They will consult with Tesla and are scheduled to come out a week from Friday. I will update the thread if they can isolate a cause.

 

[jjrandorin]

I don't think the issue was my old laser printer. I believe it only happened three times, and all within about 60 to 90 minutes. I only knew because of the sound the printer makes when it starts up. It was around noon, so no lights were on. I called it in to the company that did the install. They will consult with Tesla and are scheduled to come out a week from Friday. I will update the thread if they can isolate a cause.

Thanks for keeping us in the loop, let us know.

 

[Vines]

We are in the fire zone in Northern California so our power was turned off as scheduled last night, 10/25. Powerwall took over quickly and all seemed right. I was surprised and disappointed to learn that my Comcast Internet does not work during a power outage despite my cable modem continuing to operate. And unfortunately, because we live in the Oakland Hills, our cell phone connection is weak. I’m using it now through Bluetooth, but it is slow.

in any case, I was satisfied overall, the battery went down to around 50% and started recharging this morning through solar, and is now back to 100%. So everything else worked as planned. However, around Noon and then twice again in the next hour, the power went off and immediately came back on. I don’t think this was PGE. My Comcast Internet connection never came back and there was no change in the schedule of power from PGE not being restored until tonight. So why did the power recycle? Should I call Tesla? Did this happen to anyone else?

What was the SoC of the Powerwalls when the outages occurred?

 

[jboy210]

Are you aware of the frequency issue for cutting off inverters when the grid is down and Powerwalls are full (or close to full)? The way it works is that the Gateway increases frequency until the inverters cut off since it cannot ship excess power to the dead grid. This frequency increase can cause devices such as UPS, computers, printers, etc. to shut down.

The fix is to contact Tesla and have them reset your Gateway to not raise the frequency any higher than necessary to take the inverters offline when the Powerwalls are full.

This long thread goes into all the details.

 

[Vines]

Are you aware of the frequency issue for cutting off inverters when the grid is down and Powerwalls are full (or close to full)? The way it works is that the Gateway increases frequency until the inverters cut off since it cannot ship excess power to the dead grid. This frequency increase can cause devices such as UPS, computers, printers, etc. to shut down.

The fix is to contact Tesla and have them reset your Gateway to not raise the frequency any higher than necessary to take the inverters offline when the Powerwalls are full.

This long thread goes into all the details.

This is what I suspect is the problem as well.

 

[jjrandorin]

I didnt think of "power outage" as the frequency issue, but yeah I can see that now (good catch @jboy210 ). That issue can cause lights to flash, microwaves to not run properly (and yeah I could see an old laser printer not liking 65 hz).

@RobbL

A high level summary of the issue is, when the following happens:

1. House running in microgrid format because there is a power outage.
2. Powerwall state of charge is full or almost full
3. PV panels on and generating power

The powerwall gateway will raise the frequency of the power from a standard 60Hz to "a higher frequency" to shut off the solar panels, because the PV power has no place to go if the powerwalls are full and there is no grid. The default frequency is 65Hz (in the US, not sure what it is in other countries but the effect is the same). 65hz is "out of spec" for many (many many) electrical items in the US, and can cause random issues like lights flickering, microwaves not working properly, plug in UPS devices behaving like there is no power when there is power, things with motors running faster, or not at all etc.

The powerwall outputs this higher frequency until it drains enough to accept more power from the powerwalls, then lowers the frequency (which allows the inverters to come back on and solar to generate), and will repeat this process if the powerwall gets full.

The fix for this is to ask tesla to lower the frequency that turns off the solar panels to a lower one that still turns them off. The thread that @jboy210 linked to likely has a lot more details, but thats a summary. You can test the frequency yourself with a kill a watt type device that shows frequency when plugged in, and having your powerwalls full, while the sun is shining and you are producing power, then turning your main home breaker off to simulate a power outage.

I would recommend looking at this situation before having tesla come out in person. I agree with both @Vines and @jboy210 that its likely that this caused your lights to flicker and the laser printer to reboot.

 

[jboy210]

I agree with both @Vines and @jboy210 that its likely that this caused your lights to flicker and the laser printer to reboot.

I KNOW it will cause the lights to flicker and printer to cycle (and refrigerators to make strange noises). I tried it before calling Tesla.

In hindsight that was a pretty stupid thing to do on my part because I could have trashed my UPS units or something else.

I suggest just calling Tesla and seeing how far they can lower the frequency. And THEN trying a test to make sure everything survives the PW full inverter shutdown at the lowered AC frequency.

 

[MorrisonHiker]

We haven't seen any power fluctuation when running our TEG when the grid is down. If the OP's system is experiencing brief outages while operating off-grid, the system should be checked.

We have Comcast in the Houston area. When we've had extended outages after hurricanes, we've lost grid power - but our Comcast phone, internet and TV service continued. Comcast evidently has separate power to operate their network (at least in our area) even if the grid power is out.

Sometimes Comcast will install a signal booster to increase the signal strength inside a house. This booster requires power. If Comcast signal is lost during a power outage, it might be worthwhile to look at where the Comcast cable is coming in and check if there's a booster - and where it's being powered (if it's connected to a circuit that's not powered by the TEG).

When a derecho knocked down nearly all the power poles in our neighborhood back in June, surprisingly the internet stayed up for several hours.

A couple weeks back, they came and installed 3 Powerwall-like devices on one of the power poles in our neighborhood. Hopefully that means the internet will stay up even if the rest of the neighborhood is without power. They also installed a wrap under the batteries and transformers to help prevent squirrels and other wildlife from climbing the poles and making their home there.

 

[jboy210]

When a derecho knocked down nearly all the power poles in our neighborhood back in June, surprisingly the internet stayed up for several hours.

A couple weeks back, they came and installed 3 Powerwall-like devices on one of the power poles in our neighborhood. Hopefully that means the internet will stay up even if the rest of the neighborhood is without power. They also installed a wrap under the batteries and transformers to help prevent squirrels and other wildlife from climbing the poles and making their home there.

Cable systems usually have battery backups at various amp locations along their runs including the local heads which conditions the signal sent the last bit. According to @bmah the fiber optics systems have less of a need for this conditioning.

 

[RobbL]

In terms of the frequency issue, thanks to the forums, I became aware of that issue and at my request Tesla lowered it, I believe to 62.5 a number of months back.

The restarts happened around noon. The Powerall went down to about 50% overnight. By noon there had been recharging from solar, but only to about 70% by that point, so it was not nearly full. It took several more hours to fully recharge.