Powerwall 1.0kw maximum output

[Don_Singer]

Starting in July during peak grid energy cost from 2pm to 8pm my Powerwall outputs at most 1.0kw and any shortfall from solar comes from the grid. In the afternoon this can be as high as 6.0kw demand. During this time the Powerwall has from 50 to 100% charge. There is plenty of stored energy to use the Powerwall instead of the grid. Often at 8pm when the energy cost rate drops there is still 80% charge on the Powerwall. I’ve been waiting for Tesla Customer Service for 6 weeks now. Tier-2 said it is working normally. Once I got an agent that said he only saw a program fo Nov-June and it was a software issue, their time for that is another 3 weeks. In June from 2pm to 8pm the Powerwall would exhaust 100% charge to the minimum 10% I have set, which is what I expect it to do. Waiting for Tesla has cost me most of the summer paying max rates. Do you have any thoughts why the Powerwall does not put out more than 1.0kw.

Thanks.

 

[Don_Singer]

 

[sorka]

What happens of you disconnect from the grid?

 

[Don_Singer]

What happens of you disconnect from the grid?

I haven't been brave enough to do that. I don't want to damage any of my HVAC equipment during the hot Phoenix summer.

 

[sorka]

I haven't been brave enough to do that. I don't want to damage any of my HVAC equipment during the hot Phoenix summer.

Unlikely, but turn off your air conditioning, turn off main breaker or go off grid, and then add load until the PWs shut off. Note the wattage when they powered.

 

[Don_Singer]

I tried your recommendation, it did not go well.

I switched off both HVAC units, house drawing 0.5kw and went Off Grid. Turned on one HVAC that normally draws 2.7kw and the PowerWall was unable to start the unit and caused a brown out which took out my wifi internet. The system cannot go back On Grid without the internet. I wasn't sure if the brown out ruined my router or it was just taking a long time to boot but there were some very tense moments in the heat of summer where my house did not have access to enough power to run the AC.

Since Tesla support is only available M-F from 7am to 2pm, if someone is going to try Off Grid I recommended doing it during these times or you are on your own with no power.

 

[Don_Singer]

I put the Powewall in Self-Powered mode and was able to get it to output more than 1.0kw to partially offset grid use. So maybe the Powerwall itself if physically OK, but the Tesla control algorithms are terrible.

 

[Don_Singer]

I have four seasons created in my utility rate plan based on the utility on-peak/off-peak price structure, particularly through the summer when rates are three times higher than other seasons. My Powerwall is not outputting more than 1.0kw during peak time so most of the power for my house is coming from the grid even though my Powerwall has plenty of charge.

The Tesla agent I was finally able to get hold of said he only saw two seasons on his end, from Nov-Apr and May-Jun, with no season for July which is why the Powerwall is not working correctly.

It was alarming that the settings in the app are not used by the system as I am under the impression the app is used to control the system. This seems like a serious problem, but Tesla is in no hurry to fix it. I wonder how many other people think their system is using Time-Based Control when it actually isn't.

 

[sorka]

Interesting. There are clearly other failures going on here.

First using the "off grid" mode enabled from the app is not truly off grid. It's merely a simulation. You are not actually off grid. As long as the simulation doesn't fail, the Powerwall(s) will provide enough energy to prevent you from using the grid. The simulation will end if the TEG detects a PW malfunction or the charge level goes too low. The simulation doesn't actually physically disconnect the breaker in the TEG so if there's even an undetected failure and the PWs can't keep up, then the balance comes from the grid. The simulation also can't test forcing solar off when the PWs fill up because the way that works is the PWs change their line frequency to signal the inverters to shut down but in the simulation, the line frequency is still the grid.

A brownout isn't even possible unless the utility experienced a brownout at the same time since you are not actually disconnected from the grid.

If you disconnected by using the main service breaker, then of course anything is possible if the Powerwalls are truly malfunctioning.

Secondly, the TEG has a backup cellular modem. I was at first confused why the app still all worked for the tesla energy functions whenever my Comcast went out and turns out it's because there's an AT&T modem. Thirdly, you don't even need that to reconnect. To even enable the off-grid simulation button, you had to pair your phone to the PWs which allows you to access certain functionality like off-grid even if there's no internet connection, but you need to be close enough to the TEG for that.

Lastly, you didn't quite do what I intended. The idea was to turn everything off in the house, go off-grid, and then add load back until you exceeded 1.0 kw to see if you could get your PWs to do that. In off grid simulation mode, the simulation would end if the PWs decided they'd hit their max. In true off grid mode, with the main breaker off, the PWs would at some point reset. If just over 1.0 kw worked, continue adding load to test it. I certainly didn't mean add one huge load all at once and an AC that runs 2.5 kw continuous will pull WAY more than that at startup even with a slow start capacitor installed.

When you first had the system installed, one of the first things to test before you pay for anything is to throw the main service breaker and start up all HVACs that are backed up by the system to make sure they start without resetting the PWs.

 

[Don_Singer]

I appreciate you explanation of how Tesla says it should work, this is just one example how that is not the case. The simulated off-grid did not reach out to the grid when the PW couldn't handle it. The house brown out'ed every time the HVAC motor tried to start. It did not go out to AT&T when the wifi went down, it just error'ed out staying it failed to go On-Grid. It did ask about using mobile data but didn't actually do it.

Also, I did exactly what you intended, when I added a load the PW couldn't provide enough energy to start the HVAC motor which was my means to "add load back", there aren't enough lights in my house to ramp up to 3.0kw as a capacity test.

The PW used to be able to run my AC units just fine without the grid back in June, so I agree with you there is something else going on here.

 

[sorka]

I appreciate you explanation of how Tesla says it should work, this is just one example how that is not the case. The simulated off-grid did not reach out to the grid when the PW couldn't handle it. The house brown out'ed every time the HVAC motor tried to start. It did not go out to AT&T when the wifi went down, it just error'ed out staying it failed to go On-Grid. It did ask about using mobile data but didn't actually do it.

Also, I did exactly what you intended, when I added a load the PW couldn't provide enough energy to start the HVAC motor which was my means to "add load back", there aren't enough lights in my house to ramp up to 3.0kw as a capacity test.

The PW used to be able to run my AC units just fine without the grid back in June, so I agree with you there is something else going on here.

You’re still not understanding how it works. The TEG has no physical disconnect from your utility other than breakers you manually have to turn off. If the TEG dies or the PWs fail, you still have your utility connection. The only thing grid-mode does is control the charge or discharge rate of the PWs so that you net 0 to or from the grid. It’s literally a change to the algorithm, not any sort of physical connection disconnect. If the algorithm is wrong, the worst that can happen is you export or import energy instead of staying neutral.

 

[power.saver]

You’re still not understanding how it works. The TEG has no physical disconnect from your utility other than breakers you manually have to turn off. If the TEG dies or the PWs fail, you still have your utility connection. The only thing grid-mode does is control the charge or discharge rate of the PWs so that you net 0 to or from the grid. It’s literally a change to the algorithm, not any sort of physical connection disconnect. If the algorithm is wrong, the worst that can happen is you export or import energy instead of staying neutral.

There is a contactor in the TEG that physically opens when the grid fails, or when you go off grid.

 

[Redhill_qik]

There is a contactor in the TEG that physically opens when the grid fails, or when you go off grid.

Right, that's the whole purpose of the Gateway to prevent any electricity from going to the grid when the grid is down.

 

[sorka]

Go Off-Grid | Tesla Support

Go Off-Grid allows you to disconnect your Powerwall from your utility grid to simulate the experience of being off the electrical grid. With the ability to disconnect using the Tesla app, your Powerwall puts you in direct control of your home energy ecosystem, improving your energy independence...

www.tesla.com

A bit more detail. Interestingly, when tried this today, there is no relay sound coming from my TEG.

To the op, if you're not already out of off grid mode, try bringing your phone near the TEG. Also, if your phone is not paired, you can do so following gthe instructions in the app. Again the internet is not needed.

 

[sorka]

The results of your test should be proof enough to Tesla that you have a serious malfunction that needs an on site visit. If you're still not able to communicate with the TEG, then your cellular backup is not working or the TEG is just fried.

Have you tried resetting the PW and TEG? Have you tried their troubleshooting workflow?

Troubleshooting Your Powerwall | Tesla Support

Your Powerwall may require some basic troubleshooting from time to time. If you receive an alert, identify your issue and follow the applicable troubleshooting instructions.

www.tesla.com

 

[sorka]

Any update?

 

[Don_Singer]

I live in Phoenix and purchased Tesla solar and a single Powerwall with the intention that the Powerwall energy would be used during on-peak times when the solar is not generating enough energy. On-peak energy cost in Phoenix is three times higher than off-peak in the summer so the biggest savings is to not use grid power during on-peak. This was all working as expected up until July 1st when the Powerwall started limiting output to 1.0KW.

After seven weeks of delays and multiple calls where the initial assessment was a software error and there was not a TBC plan for July, to the wrong TBC setting (since set to Tesla recommended values) to now, "the Powerwall is getting hot and needs to limit output", which sounds plausible EXCEPT it worked fine in June when it was just as hot.

With that latest assessment Tesla is walking away from the problem. So, my summer energy bills are just at high as before I installed solar.

If you are thinking of buying a Powerwall and you live where summers are hot be aware it will not be able to provide the power you think it will.

 

[GWord]

The data sheet specifies 50C max operating range. If the installation is in the sun in Phx I wouldn't be surprised to exceed that. I suspect some sort of sun shade would probably fix your problem. I have 4 powerwalls in Houston facing south, but are somewhat shaded by some vegitation. When the sun does directly shine on one, its temp can increase by 5 to 10degC over the ones that are still shaded.

 

[jgleigh]

I've got four Powerwalls in Tucson. Mine are installed in the garage, but it still gets quite warm in there during the summer.

@Don_Singer are you sure your cooling loop and fan are working correctly? If you install something like Powerwall Dashboard you can monitor the Powerwall temps. My units were between 32-40C even during the heat of July.

GitHub - jasonacox/Powerwall-Dashboard: Grafana Monitoring Dashboard for Tesla Solar and Powerwall Systems

Grafana Monitoring Dashboard for Tesla Solar and Powerwall Systems - jasonacox/Powerwall-Dashboard

github.com

 

[Redhill_qik]

I live in Phoenix and purchased Tesla solar and a single Powerwall with the intention that the Powerwall energy would be used during on-peak times when the solar is not generating enough energy. On-peak energy cost in Phoenix is three times higher than off-peak in the summer so the biggest savings is to not use grid power during on-peak. This was all working as expected up until July 1st when the Powerwall started limiting output to 1.0KW.

After seven weeks of delays and multiple calls where the initial assessment was a software error and there was not a TBC plan for July, to the wrong TBC setting (since set to Tesla recommended values) to now, "the Powerwall is getting hot and needs to limit output", which sounds plausible EXCEPT it worked fine in June when it was just as hot.

With that latest assessment Tesla is walking away from the problem. So, my summer energy bills are just at high as before I installed solar.

If you are thinking of buying a Powerwall and you live where summers are hot be aware it will not be able to provide the power you think it will.

I would not be giving up on getting this fixed and your posts are the first that I have seen here reporting export limitation in this way. AS @GWord pointed out, the Powerwall datasheet lists 50C (122F) as the maximum operating temperature. Looking at the historical weather for Phoenix, AZ on 8/13/2023 when you first posted the max was 108F which is below the rated specification. Your Powerwall may be outside and in full sun and therefor in a hotter environment, but there isn't any data that confirms this:

There have been issues with Powerwall coolant leaks and maybe that is what is happening, maybe the internal temp sensors are off and that is what is happening, but either of this should be fixed under warranty.

I think that you need to verify that you can get the full 5kW out of the Powerwall in a cool environment. You tried going off grid and turning on the HVAC, but that didn't work as the HVAC startup is too much for the Powerwall to handle. I am very surprised that your AC unit is backed up load with only a single Powerwall. So, instead in the cool morning with your HVAC off, go off grid and just start turning on lights and electric appliances (oven, stove, microwave, etc) to ramp your load from the 0.5kW base up to 3+kW. If the Powerwall can't handle that then there is a serious problem.