Read it more closely, you might be write about this. It says " During Preconditioning, the Power Flow screen may show energy flowing to your Powerwall from solar or the grid. This is normal behavior, and the energy is only being used to heat, not to charge."
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Powerwall 2 + UPS Connundrum - and solution
- Thread starter NinjaVece
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Read it more closely, you might be write about this. It says " During Preconditioning, the Power Flow screen may show energy flowing to your Powerwall from solar or the grid. This is normal behavior, and the energy is only being used to heat, not to charge."
woferry
Member
I've never seen my PW pull from the grid. If I dip below the reserve level before the sun comes up, what I see is that early solar goes only to the PW while the house continues to draw from the grid, then once the reserve is reached you get the more normal "PW gets what solar the house doesn't need" behavior. But in preparation for the morning charging I do hear the unit's pump running and it does draw itself below the reserve if it had previously stopped due to hitting it.
aesculus
Still Trying to Figure This All Out
Curious about this as I have seen this too. So my reserve is 60% and the night before I can see it stops at that level. The next morning when the sun is just shining and I am producing about 500 Watts of power I can see that the PW SoC is like 57%. The outside temp is within a few degrees of what it was the night before so I don't think it's the temperature change.
So are you stating that somehow the PW's know (expect?) that charging will take place and it will need to condition itself to accept the inbound current so it depletes it's own store to do this?
If so, why does it not just take this power from the grid like any other appliance?
woferry
Member
All I know is what I see/hear, in terms of policy reasons that would be more of a question for Tesla. But yeah, Sunday was a really overcast/rainy day and I wasn't able to fill my PW (only got up to 60%), so it didn't last overnight like it usually does, around 2am I heard it go silent as it hit my 0% reserve. But around 6am it started making noise again (my sleep schedule is totally hosed with this whole stay-at-home deal.. 
), the solar inverters weren't online for about another hour. I don't know if it might run afoul of some of the ITC/SGIP/whatever rules for it to draw directly from the grid for this, or maybe it's more of an assumption that they can't rely on the grid always being there, I don't know.
Honestly, I'd like to know more about just how much work the internal pump is doing, what sort of temperature range it's trying to regulate to, etc. I hear my PW a lot (it's not annoying, but it is noticeable), including times where the loads should be pretty low (<1kW) and the temperatures very moderate, so I really don't know if it's cooling itself, or warming itself, or what. It does occasionally go quiet, but usually not for more than a minute or two before you can hear it again. Without knowing any facts, it feels to me like it's working harder than it should have to, and probably costing some lost efficiency in the progress. I'd hope it's all for good reason, I'd just feel better if it was explained somewhere.
), the solar inverters weren't online for about another hour. I don't know if it might run afoul of some of the ITC/SGIP/whatever rules for it to draw directly from the grid for this, or maybe it's more of an assumption that they can't rely on the grid always being there, I don't know.Honestly, I'd like to know more about just how much work the internal pump is doing, what sort of temperature range it's trying to regulate to, etc. I hear my PW a lot (it's not annoying, but it is noticeable), including times where the loads should be pretty low (<1kW) and the temperatures very moderate, so I really don't know if it's cooling itself, or warming itself, or what. It does occasionally go quiet, but usually not for more than a minute or two before you can hear it again. Without knowing any facts, it feels to me like it's working harder than it should have to, and probably costing some lost efficiency in the progress. I'd hope it's all for good reason, I'd just feel better if it was explained somewhere.
All I know is what I see/hear, in terms of policy reasons that would be more of a question for Tesla. But yeah, Sunday was a really overcast/rainy day and I wasn't able to fill my PW (only got up to 60%), so it didn't last overnight like it usually does, around 2am I heard it go silent as it hit my 0% reserve. But around 6am it started making noise again (my sleep schedule is totally hosed with this whole stay-at-home deal..
Honestly, I'd like to know more about just how much work the internal pump is doing, what sort of temperature range it's trying to regulate to, etc. I hear my PW a lot (it's not annoying, but it is noticeable), including times where the loads should be pretty low (<1kW) and the temperatures very moderate, so I really don't know if it's cooling itself, or warming itself, or what. It does occasionally go quiet, but usually not for more than a minute or two before you can hear it again. Without knowing any facts, it feels to me like it's working harder than it should have to, and probably costing some lost efficiency in the progress. I'd hope it's all for good reason, I'd just feel better if it was explained somewhere.
I have the same questions about the PWs. Is there an API where we can get info on the heaters and the fans?
I put a USB temp recorder in the garage next to the PWs so I could record the ambient temp. So far it has only gone down to 45F, so I am hoping that means minimal heating. But this summer, our garage gets pretty warm, so perhaps the fans will be running a lot.
aesculus
Still Trying to Figure This All Out
Tesla came out and inspected/tested my PWs with full charge and solar. They were originally set to 65 Hz. They lowered them to 63Hz but my Insteon Hub and UPS would not operate at that frequency. So they lowered it to 62 Hz after a fair amount of discussion. The UPS now works correctly but the Insteon devices will not respond. Not sure if that is the Hub issue or that the devices themselves will not operate at that frequency. I did not try a device to device test.
I asked Tesla to try 61 or even 61.5 but they did not want to go any lower. At this point I will just live without the Insteon devices working in that rare time when the battery is full. It won't be more than a few hours after late afternoon during a power outage that the system will incented to turn off the inverters so it's not a big deal.
I asked Tesla to try 61 or even 61.5 but they did not want to go any lower. At this point I will just live without the Insteon devices working in that rare time when the battery is full. It won't be more than a few hours after late afternoon during a power outage that the system will incented to turn off the inverters so it's not a big deal.
I have this vague memory of Insteon powerline devices working up to around 62.5-63.0 Hz. I might have written that up in a forum post. (EDIT: That was post #213 in this very thread...Powerwall 2 + UPS Connundrum - and solution) Also note if you have dual-band Insteon gear, the wireless inter-device links might work better than powerline links (I've been slowly replacing old Insteon devices with their dual-band equivalents). I have a different controller (ISY-994i with a dual-band PLM), so that might behave differently than the Insteon Hub.
Bruce.
aesculus
Still Trying to Figure This All Out
I am in the processes of dumping the hub and have configured all my devices on the ISY too but have not made the switch yet lacking a good mobile UI. Don't really want to expose my credentials or my device to a 3rd party so I need to get busy and write up something specific to my needs.
Hopefully that will fix this issue if your analysis of it working at 62 Hz is correct.
There's a definite vacuum in the area of self-contained, mobile ISY front-ends. I liked the old Mobilinc (before they decided to go all cloud-based) or CtrlHome (before it stopped working for me) but I always felt to me like it was possible to do something "better".
(Sorry for the off-topic!)
Bruce.
NathanielHrnblwr
Member
Back on 3/13 I called Tesla to adjust the frequency down from 65 like others have done and they insisted on sending someone out. Soonest was this week.
Good news! They didn't forget about the appointment and Tesla guy was here right at 8am. He understood what I was asking, saw my UPS, saw the Kill-A-Watt and called the same # I did to get it adjusted. Got tier 2 on the line and they adjusted the frequency down. Tier 2 said it was dialed down to 62.2 but Kill-A-Watt reads 63. They wouldn't adjust it down further as my UPS's never stayed on battery long enough to beep during the simulated power outage. I was hoping to get a bit of a buffer as they have a +/- of 3 Hz and 63 is right at the top end, but none of the units seems to be cycling back on battery. Power outages here aren't frequent and this is a edge case scenario so all is good for now.
Good news! They didn't forget about the appointment and Tesla guy was here right at 8am. He understood what I was asking, saw my UPS, saw the Kill-A-Watt and called the same # I did to get it adjusted.
Got tier 2 on the line and they adjusted the frequency down. Tier 2 said it was dialed down to 62.2 but Kill-A-Watt reads 63. They wouldn't adjust it down further as my UPS's never stayed on battery long enough to beep during the simulated power outage. I was hoping to get a bit of a buffer as they have a +/- of 3 Hz and 63 is right at the top end, but none of the units seems to be cycling back on battery. Power outages here aren't frequent and this is a edge case scenario so all is good for now.Devices should operate at up to 63Hz. Our solar cutoff frequency was set to 61.5 (because our solar panels shut off above 60.5). And that appears to have fixed our issues.
Though for some reason, we have one Cyberpower UPS that refuses to work at all while we're running off-grid using PowerWall power - no matter what the frequency. When that UPS senses even a short break in the power, it goes offline and requires a manual reset to get it to power any devices. Didn't have that issue before we installed our solar/PowerWall system - could be that the UPS gets confused when it gets a short interruption of power (which could be a design flaw or a problem with that UPS) - and because we have less need for UPS now, it was easier to take that UPS out of service and not worry about it...
Though for some reason, we have one Cyberpower UPS that refuses to work at all while we're running off-grid using PowerWall power - no matter what the frequency. When that UPS senses even a short break in the power, it goes offline and requires a manual reset to get it to power any devices. Didn't have that issue before we installed our solar/PowerWall system - could be that the UPS gets confused when it gets a short interruption of power (which could be a design flaw or a problem with that UPS) - and because we have less need for UPS now, it was easier to take that UPS out of service and not worry about it...
Adding another mechanical device to the system creates another possible point of failure. If they would just look at the list of installed equipment and set the proper frequency limits when first provisioning the systems, it would not be a problem and we wouldn't have anything to talk about.
Because frequency control is a better solution. Newer inverters, and all off-grid inverters, use this method to curtail production as batteries get full. It also allows the inverters to operate at reduced output during periods when load is less than solar production. With a simple contactor, it's just an on-off switch, and the lag time in restarting inverters causes them to be off-line longer than necessary.
The problem is Tesla chose a frequency that is too high, and causing unintended problems with UPS and other electronic devices in the home. Since older inverters don't have the frequency control feature, they will simply turn off, but do so at a much lower frequency. They should look at the attached equipment, and run a test during commissioning, so it can be set appropriately.
Why is frequency a better solution? It seems like a recipe for problems as people can always add devices after installation that don't work with 65Hz, 62Hz, etc as there is no regulation that requires electronic devices to work with those frequencies. I understand grid tied inverters have traditionally used this mechanism but it doesn't mean it's a good idea to continue. It seems like a hack. An out of band mechanism would be much more robust.
It's not a hack, it's literally a standard. Every utility interconnect agreement in the United States require adherence to IEEE 1547 and certified by UL 1741. The standards have been defined and refined over the years as a partnership between industry and utilities, they're used all over the world.
1547-2018 - IEEE Standard for Interconnection and Interoperability of Distributed Energy Resources with Associated Electric Power Systems Interfaces
UL - 1741 Standard for Inverters, Converters, Controllers and Interconnection System Equipment for Use With Distributed Energy Resources | Standards Catalog
https://www.nrel.gov/docs/fy15osti/63157.pdf
The reason that frequency (and voltage) are used to trip connections to broader grids is to manage and respond to abnormal grid operations. At the end of things yes, a relay or switch is needed to physically island microgrids. That's what the Powerwall does.
I understand it's part of a standard to force grid tied inverters shutoff off the grid in case of abnormal conditions but the original intention is not to have electronic devices to continue to operate under the abnormal frequency which is what hybrid inverters including Powerwall is doing. Otherwise there would be additional standard/regulation to require electronic device manufacturers to make their products work with frequencies outside of the regulated grid frequency range that manufacturers follow. So, what I meant by hack is on the part of hybrid inverter manufacturers using the standard in a way it was not designed for in the first place.
I'm not following what point you're trying to make.
If you're trying to say that Tesla's decision to set the frequency max to 65hz by default is incorrect I agree - at that high of a frequency things start not working properly and grid tie inverters have long since used much lower frequencies as their cutoff.
If you're trying to say that Tesla's decision to use microgrid frequency at all to communicate with PV inverters is a "hack" then that's simply not correct.
I have my PV inverters set up to curtail production based on slight frequency increases between 60.2hz-61.4hz, a feature many inverters support. This allows the Powerwall to tell the inverters to scale up or down based on the house load and battery state of charge during a grid outage so that the inverters aren't flipping on and off constantly, allowing for smoother operation. Is that a "hack" too? Without frequency shifting there is no other way to universally communicate with PV inverters.
If you're trying to say that Tesla's decision to set the frequency max to 65hz by default is incorrect I agree - at that high of a frequency things start not working properly and grid tie inverters have long since used much lower frequencies as their cutoff.
If you're trying to say that Tesla's decision to use microgrid frequency at all to communicate with PV inverters is a "hack" then that's simply not correct.
I have my PV inverters set up to curtail production based on slight frequency increases between 60.2hz-61.4hz, a feature many inverters support. This allows the Powerwall to tell the inverters to scale up or down based on the house load and battery state of charge during a grid outage so that the inverters aren't flipping on and off constantly, allowing for smoother operation. Is that a "hack" too? Without frequency shifting there is no other way to universally communicate with PV inverters.
It's fine for Tesla and other hybrid inverter manufacturers to use frequency shifting if they just want to shutdown grid tied inverters just like the utilities would do. However, it's not fine to use frequency shifting to shutdown grid tied inverters AND expect other electronic devices in general to function with frequency shifting. Utilities have no expectation for electronic devices in general to function properly with frequency shifting.
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