HankLloydRight
No Roads
The only reason I ask is that I have a pretty old APC UPC for my computer, and it seems to have no problems when there's a power outage and the PW kicks in. So I don't know if I'm affected by this or I need to get a new UPC.
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Powerwall 2 + UPS Connundrum - and solution
- Thread starter NinjaVece
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- ups 65 hertz
We have a lot of UPS systems at our house protecting computers, DVR, smart TVs, ... - basically anything that has a processor or equipment that we wanted to run for a few minutes to a few hours during a power outage.
During testing, one UPS system died (which might only be a dead battery) and one UPS system that turns off whenever there is a grid/off-grid change by the TEG.
Now that we have the PowerWalls, the UPS systems are only needed to provide power for a few seconds, to avoid "rebooting" when there is a grid/off-grid change. We'll likely replace some of the UPS systems with surge protector strips. And for anything that we don't want to "reboot" during change, we'll have a UPS - but can probably get buy with much smaller systems, since we only need a few seconds of coverage - not minutes or hours.
For the two UPS systems that are having problems, I'll probably just take them out of service - and in the future, if we do need a new UPS, I'll go with the smallest UPS system and connect only equipment that want to run for a few seconds during the switchover.
During testing, one UPS system died (which might only be a dead battery) and one UPS system that turns off whenever there is a grid/off-grid change by the TEG.
Now that we have the PowerWalls, the UPS systems are only needed to provide power for a few seconds, to avoid "rebooting" when there is a grid/off-grid change. We'll likely replace some of the UPS systems with surge protector strips. And for anything that we don't want to "reboot" during change, we'll have a UPS - but can probably get buy with much smaller systems, since we only need a few seconds of coverage - not minutes or hours.
For the two UPS systems that are having problems, I'll probably just take them out of service - and in the future, if we do need a new UPS, I'll go with the smallest UPS system and connect only equipment that want to run for a few seconds during the switchover.
HankLloydRight
No Roads
Yeah, all of our computers are laptops, so their internal battery kicks in... except for my desktop "work" machine which is on the UPS to cover the switchover interruption. The only thing that isn't is the cable modem, so we get a reboot on that. I think I need to get or build a "mini-UPS" that cover a brief outages like this.
If your current UPS "seems to have no problems" and you have already had outages since getting your powerwall, then it sounds like you already know whether you are impacted by this?
From first-hand observation, yes it does. (Don't know about the case of a house without solar.)
This once led to the totally counter-intuitive act of charging my Model S from Powerwalls during a power outage (at night). I needed to soak up just enough energy to get them to go back to 60Hz so several UPSs in my house would stop beeping and we could go back to sleep.
Bruce.
From my testing the frequency the PW sets during off-grid operation is a function that takes battery SoC and load in to account (but not solar production), with the SoC seeming to be the primary component. Since Tesla can configure the maximum frequency I assume they can also change the formula's parameters a bit.
In this example normal frequency is 60hz, high is 62hz.
High SoC, low load = 62hz
Low SoC, low load = 60hz
High SoC, high load = 61hz
Low SoC, high load = 60hz
Utility outage simulation data dump
@bmah this would be why your "hack" worked
In this example normal frequency is 60hz, high is 62hz.
High SoC, low load = 62hz
Low SoC, low load = 60hz
High SoC, high load = 61hz
Low SoC, high load = 60hz
Utility outage simulation data dump
@bmah this would be why your "hack" worked
aesculus
Still Trying to Figure This All Out
Had you asked Tesla to set your high frequency to 62 hz or was this the default? Curious as others are reporting theirs gets set to 65 hz.
Interestingly enough I actually didn't request a specific frequency - I told Tesla support I was having issues with my LED lights and UPS, they asked me what the make/model of my inverters are and then they made the change on the back end. I found they set it to 62hz after my own testing.
JPP
Active Member
Well since even with my up front request to fix the frequency (...after reading this thread), my PW system was commissioned 'out of the box' with the PW2s switching (not ramping) up to 65Hz. I would doubt that Tesla does anything special for solar or 'non solar' customers. Me, I have now had 3 calls to Tesla Powerwall Support, and they insisted yesterday to have me run an 'off grid' test for them while they monitored my system in real time. The test was run, they wanted to observe for 5 minutes, and then thanked me and said that they would get back to me. Note that I had done this myself previously to see the 65Hz. And they said yesterday that tier 2 support insisted on this test observed by their support tech before they would accede to my request. So now I wait for them to review the data (and I had previously been asked to give them make and model of my UPS---FWIW I have APC and CyberPower UPS which I know from testing tolerate 62Hz).
Are you positive there was no ramp? As my testing showed there is clearly a ramp that is based primarily on SoC but also load.
JPP
Active Member
No, I am not sure. I don't have the data as you do. I was asked to test with PW battery fully charged and saw 65Hz. So, no, I don't know what it should do. But I do know that if my system goes 'off grid' with the PWs at 100%, my UPS go off line too.
HankLloydRight
No Roads
I asked because I don't know if there' something I'm missing. I see everyone ditching the APC UPSs for the Eaton ones, but don't really know if I need to do that. What are the symptoms of the APC UPSs not working?
Those changeovers seem to be because the Eaton UPS could tolerate 65 Hz. I am hoping that Tesla will turn my down to trigger frequency to 62 Hz or less from the beginning so I don't have to replace all of the APC UPS's we have.
JPP
Active Member
The issue is that the UPS should take over when the grid goes down and should let the grid provide power when the grid is up. If your PWs are operating and providing power, then the UPS should not be running on battery. But if the UPS see 65Hz as a 'bad grid' then the UPS will stay on internal battery until their batteries die, then your UPS shuts down and any attached equipment shuts down. We want the UPS to do their thing for the fraction of a second it takes for the PWs to take over, but to not run down their internal batteries if the PWS are providing 'good' power.
JPP
Active Member
With any luck you won't have to replace the UPS, but you will need to pester Tesla Powerwall Support as I have done in the hopes that they will make the change. iI should not be that difficult.....
aesculus
Still Trying to Figure This All Out
FWIW I did a test on my two powerwalls with Fronius inverters that trip outside of 59.5 - 60.5 Hz.
Before turning off grid power I was at 59.9 Hz and when turned off it slowly (1 minute) climbed to 64.5 Hz and stayed there. Of course the solar inverters went into error mode and turned off.
Restoring grid power took about 30 seconds for the PW to switch back to grid power and about a minute to set the frequency back down to 59.9 Hz. And then 5 minutes or so for the inverters to reboot and come back on line.
All this of course with the PWs at 100%.
Before turning off grid power I was at 59.9 Hz and when turned off it slowly (1 minute) climbed to 64.5 Hz and stayed there. Of course the solar inverters went into error mode and turned off.
Restoring grid power took about 30 seconds for the PW to switch back to grid power and about a minute to set the frequency back down to 59.9 Hz. And then 5 minutes or so for the inverters to reboot and come back on line.
All this of course with the PWs at 100%.
mspohr
Well-Known Member
Interesting that it took it a full minute to go up to 64.5 Hz. I'm sure the inverters shut off well before it got to that frequency. Don't know why they don't just stop increasing the frequency as soon as the inverters shut off. This would help keep the UPSs happy.
JPP
Active Member
FWIW with both of my 'grid disconnect' tests the PW2s went to 65Hz immediately--no ramp.
I think there are two "ramps" that could be confusing.
If the grid disconnects while the Powerwall is fully or close to fully charged then it will set the frequency to the max instantly. No "ramp". I'm not sure I understand the behavior @aesculus mentioned because my testing shows this to be instant.
If the grid disconnects while the Powerwall has the ability to charge then the frequency will stay below the max and slowly increase to max as the Powerwall charges. Once the frequency is too high for the PV then solar production will stop, the Powerwall will start to drain and the frequency will start to decrease back towards 60hz. This is a "ramp".
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