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Powerwall 2 + UPS Connundrum - and solution

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Well, keeping the line frequency at 63Hz or below is fine. And non-ECM motors are run cooler at their design frequency. So will power supplies that use a line frequency transformer. But any computer supply made in the last couple of decades is an AC to DC converter with a transformer that runs at >20kHz. AC to DC converters that incorporate power factor correction circuits have in principle a limited frequency range, but the range is broad compared to 60Hz or 65Hz. Converters that are small enough to not need PFC will operate even with a DC input. The Intel paper is describing the minimum input frequency range needed for ATX compliance; actual power supplies built today significantly exceed the range.
Thank you sir.
 
Well, keeping the line frequency at 63Hz or below is fine. And non-ECM motors are run cooler at their design frequency. So will power supplies that use a line frequency transformer. But any computer supply made in the last couple of decades is an AC to DC converter with a transformer that runs at >20kHz. AC to DC converters that incorporate power factor correction circuits have in principle a limited frequency range, but the range is broad compared to 60Hz or 65Hz. Converters that are small enough to not need PFC will operate even with a DC input. The Intel paper is describing the minimum input frequency range needed for ATX compliance; actual power supplies built today significantly exceed the range.

Curious if you an example of a power supply that is spec'd higher than the ATX range max of 63hz. Both EVGA and Corsair publish their "AC Frequency Input Range" as 50-60hz.
 
@wbhokie and @thegdgteer I can't stress this enough: do not use the Eaton UPSes without asking Tesla to lower your maximum frequency.

Tesla does not change the min/max frequencies with firmware updates. This is a one-and-done exercise.

Thanks for the feedback and info @gpez. I'll try to give Tesla a call soon to see about reducing the maximum frequency. Sounds like requesting 62Hz is the suggested request with them coming back at something between 62 and 63, and the number is 877 961 7652. Any other tips or corrections would be appreciated, thx.
 
Any other tips or corrections would be appreciated, thx.
Always have something you tested and does not work at the higher frequency. Best to tell them x device needs y frequency or lower.

They won't adjust something just because you want it that way. And even then there were some lighting devices that they basically blew off on my lowering demands. It will be so infrequent that I decided I could live without the lights or find another way to turn them on if need. So I got to 90% of my issues and called it a win.
 
Always have something you tested and does not work at the higher frequency. Best to tell them x device needs y frequency or lower.

They won't adjust something just because you want it that way. And even then there were some lighting devices that they basically blew off on my lowering demands. It will be so infrequent that I decided I could live without the lights or find another way to turn them on if need. So I got to 90% of my issues and called it a win.
They changed for me just because I wanted it that way. They changed to 62.5
 
Thanks for the feedback and info @gpez. I'll try to give Tesla a call soon to see about reducing the maximum frequency. Sounds like requesting 62Hz is the suggested request with them coming back at something between 62 and 63, and the number is 877 961 7652. Any other tips or corrections would be appreciated, thx.

Happy to help!

If you can check what your inverters are configured to shut down at and go just a bit (0.1hz - 0.5hz) above that, that'd be optimal. My inverters are configured to operate normally from 60.0hz - 60.2hz, ramp down from 60.2hz - 61.4hz, and turn off at 61.4hz+. Powerwall is set to 62.0hz max.

Always have something you tested and does not work at the higher frequency. Best to tell them x device needs y frequency or lower.

They won't adjust something just because you want it that way. And even then there were some lighting devices that they basically blew off on my lowering demands. It will be so infrequent that I decided I could live without the lights or find another way to turn them on if need. So I got to 90% of my issues and called it a win.

+1 to this. Induction cooktops, microwaves, LED lights, UPSes are all good candidates.

They changed for me just because I wanted it that way. They changed to 62.5

They didn't really ask me either, but having a couple of devices ready to go in case they do is good :)
 
If you can check what your inverters are configured to shut down at and go just a bit (0.1hz - 0.5hz) above that, that'd be optimal. My inverters are configured to operate normally from 60.0hz - 60.2hz, ramp down from 60.2hz - 61.4hz, and turn off at 61.4hz+. Powerwall is set to 62.0hz max.

Sounds like 62.5 is a common change value but any suggestion on how to find this info about the inverters? Seems unusual they lowered to 62.0hz max?
 
Sounds like 62.5 is a common change value but any suggestion on how to find this info about the inverters?
You can check the specs on-line for every inverter. But newer ones actually trip out between 59.5 and 60.5 Hz. So even at 62 Hz Tesla is being super generous.

I sort of wish you could tune your inverters within a range. So for example I have three inverters and it would be great to have each one drop out .5 Hz over the next. This way I could incrementally have solar vs the all or nothing approach we have now. I could create some sort of table based on kW and time of day that tripped various inverters off based on what the PWs and/or my home could absorb. A bit complex but doable. Maybe in 10 years.
 
You can check the specs on-line for every inverter. But newer ones actually trip out between 59.5 and 60.5 Hz. So even at 62 Hz Tesla is being super generous.

I sort of wish you could tune your inverters within a range. So for example I have three inverters and it would be great to have each one drop out .5 Hz over the next. This way I could incrementally have solar vs the all or nothing approach we have now. I could create some sort of table based on kW and time of day that tripped various inverters off based on what the PWs and/or my home could absorb. A bit complex but doable. Maybe in 10 years.

Many inverters support gradual production curtailment based on frequency. My Enphase IQ6s do. What inverters do you have?
 
Many inverters support gradual production curtailment based on frequency. My Enphase IQ6s do. What inverters do you have?
I have two Fronious which trip at 60.5. I have one Delta M but I have not checked what its trip frequency is.

How does the "gradual" production work? Does your inverter have multiple strings it can add and subtract? My two Fronious are one string each and my Delta has two "strings".

The Delta M manual states:
Frequency range 59.3 Hz to 60.5 Hz
Not sure if this is how you take advantage of what we are discussing.
Adjustable frequency range 50 Hz to 66 Hz
 
Many inverters support gradual production curtailment based on frequency. My Enphase IQ6s do. What inverters do you have?
I'm not poster this question was directed to, but...
I believe that nearly all grid-tied inverters sold in CA or HI since (I believe) sometime in 2019 must provide a "frequency-watt" capability as part of the 1741 SA rule. In California this requirement is included in Rule 21. Here's PG&E's graphical representation of the function. SCE's is very similar.
One can see why it isn't desirable to have the PW output less than 62Hz, and I guess 63Hz might be safer.

PGE_F-W.png
 
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I forget what the PW Gateway does as it starts to get full. Does anyone have a frequency capture over time as the PWs go from about 90% to 97% SoC?

Yes, I did this during my yearly outage simulation and back in 2019 when I tried the first time.

I found that the frequency that the Powerwall provides is likely a function primarily of battery charge ("state of charge" or "SoC") and to a lesser extent the load. As an example (your settings/setup may be different):

High SoC, low load = 62hz
Low SoC, low load = 60hz
High SoC, high load = 61hz
Low SoC, high load = 60hz

It's not super easy to show since there are 3 axis but the grey line is the frequency (as a % of 60hz), blue is the Powerwall SoC, and the Load Power is how much the house was pulling. Time series is in seconds, did about a 3.5 hour simulation.

1620142436357.png


This second chart shows the Frequency (hz), battery charge, and solar + load. You can see in the middle how the solar power stays pretty close to the load power and adjusts as the sun comes in and out.

1620143093756.png
 
How do you (the system?) define High Load? Would it be a percent of the solar capacity or the PW power?

No idea, which is why I was giving just a general example. Anecdotally I've seen my frequency go from 60hz at about 94% SoC and 62hz at 100% SoC, but then going from 500w to 1500w of load reduces frequency by about 0.1hz. I'm sure there's some algorithm or math involved but I haven't been able to figure it out.
 
Curious if you an example of a power supply that is spec'd higher than the ATX range max of 63hz. Both EVGA and Corsair publish their "AC Frequency Input Range" as 50-60hz.

Corsair support stated that if the Eaton UPS supports 65hz and is in front of their PSU, then it is completely safe to use their power supply in the 63-65Hz range.

As far as the ATX Spec, that only requires that a power supply must operate in the 47-63 range.

I do agree with you that it is better to stay within the normal ranges for optimal operating conditions. At the same time, we aren't really talking long term here. Even in the rare occurrence when an outage takes place, the frequency spike doesn't last very long. Either way, a phone call is much easier than changing your UPS units to be sure, and is all around safer for all of your home electronics. You can't put a UPS in front of everything.

It certainly is annoying that Tesla insists in using such a high frequency as their default setting. They could set it a bit lower and save us all a lot of trouble.
 
Just got off the phone with Tesla Energy support. They asked for my UPS model so I gave them my Cyberpower CP1000AVRLCD. I didn't ask for a specific frequency but I would expect it would be somewhere 63Hz or lower given that's the max on that UPS. They said it needs to be escalated to Level 2 support for the change and they'll get back to me to confirm in a couple days. I'll confirm what they come back with.
 
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Just got off the phone with Tesla Energy support. They asked for my UPS model so I gave them my Cyberpower CP1000AVRLCD. I didn't ask for a specific frequency but I would expect it would be somewhere 63Hz or lower given that's the max on that UPS. They said it needs to be escalated to Level 2 support for the change and they'll get back to me to confirm in a couple days. I'll confirm what they come back with.
I guess I got lucky since I did not have to provide any devices to prove I needed the change.