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Powerwall 2 + UPS Connundrum - and solution
- Thread starter NinjaVece
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- ups 65 hertz
jrweiss98020
Tessa's Tesla
I don't think so...
My PV panels and microinverters supply power to the house and/or to recharge the PWs when the grid is disconnected. There is no 5-minute delay on solar production that I am aware of. When I inquired of my installer, he told me it is the Gateway is the automatic transfer switch that samples the grid power and disconnects/reconnects.
I think he means the 5 minute delay is when the grid is back up, that there Is a delay before the Gateway reconnects the PV to the system.
NathanielHrnblwr
Member
Can you ELI5? This sounds interesting to learn about but I don’t know what that exactly means.
AC power is a 60Hz sine wave (in North America). If the power on the disconnected micro-grid is exactly synchronized to the same voltage and phase, then there is actually no difference whether the automatic disconnect switch in the Gateway is open or closed. When the switch is closed in the synchronized state, there is no discontinuity in the power waveform, so connected loads can't tell there was any transition from the islanded to the grid-tied operation state.
If there is any interruption when the grid failed and the Powerwalls took over supplying the loads, the solar will stop producing and the 5 minute timeout will also apply. Solar production will be delayed until that time passes. I have seen this every time I looked at the intraday chart for a day that had an outage. The Gateway is only disconnecting the grid when it's outside the pre-set parameters. When the grid goes back to normal after the solar and Powerwalls have been running for some time, the PV should not notice, as explained in the section above.
HankLloydRight
No Roads
Just to chime in, the 5 minute delay happens even without solar. We have no solar, and with one PW, when there's even a short grid outage, it still takes 5 minutes for the gateway to switch back to grid power.
jrweiss98020
Tessa's Tesla
The PV is always connected to the PWs and house circuits, unless you manually open the PV disconnect switch. The Gateway's transfer switch disconnects the grid from the house system. The house system - PV and PWs - operate independently of the grid when the grid is disconnected, and there is no delay for the PV operation.
There is if the PV is forced off because the PWs are full. If that happens, then there is a delay before the PV will turn back on again.
I hadn't worried too much lately about the 65 Hz problem as we have been through several reasonably short power failures in the last few months and no problem as perhaps the PW2s were not at 100% SOC. Since we were expecting a storm to hit, yesterday I upped my reserve in TBC to 70% just in case, and this morning at 8:38 indeed there was a local power failure. My 2 PWs were at 66% and no solar yet that morning as the panels were still covered in snow. When the PW2s took over the lights started blinking and UPSs beeping even though the SOC was 66%. The frequency was 65.2 Hz.
Now 50 minutes later the frequency is still at 65 Hz and the SOC has dropped to 60%. The snow is largely melted and it sure would be nice if the PW2 would let the solar do its thing. Then as I was typing this, I heard the fan on the fireplace come on and the refrigerators start to hum, and indeed, the frequency was now 60 Hz as the grid came back on. This extended 65 Hz time seems to be a new and not very nice behavior. I guess I will have to call and get them to lower my solar turnoff frequency after all. Anyone else seen this?
Now 50 minutes later the frequency is still at 65 Hz and the SOC has dropped to 60%. The snow is largely melted and it sure would be nice if the PW2 would let the solar do its thing. Then as I was typing this, I heard the fan on the fireplace come on and the refrigerators start to hum, and indeed, the frequency was now 60 Hz as the grid came back on. This extended 65 Hz time seems to be a new and not very nice behavior. I guess I will have to call and get them to lower my solar turnoff frequency after all. Anyone else seen this?
aesculus
Still Trying to Figure This All Out
I would call them but it is interesting that the frequency was set to 65 Hz when the PWs were not fully (or nearly) fully charged and solar COULD have been available.
Interesting. That makes me believe that this is intentional to prevent charging when the batteries are cold. However, it would still be good for you to get the high frequency lowered to just what your inverter needs so lights don't flicker and UPS don't run down.
Agreed. Thanks. 34° F is not THAT cold. The car at least allows slow charging at that temperature and in this case the charging from solar that early in the AM with partial snow on the panels should have been OK. Perhaps the PW2 should try solar charging and if it gets to fast, then raise the frequency and at least one of my inverters would have shut down perhaps allowing the solar charging to continue from the other.
I wonder if some of this is the reserve a Powerwall sets aside for Precondition and cold weather operation. The information says it will effect the displayed percentages, but not how it effects it. It is at the bottom of this page, Additional Powerwall Modes | Tesla
From the link provided it seems that preconditioning uses either grid or solar power to heat the PW2 rather than charge them. But during a power failure and a cold battery, it would seem wise to use some internal energy for preconditioning so that (solar) charging might be facilitated. This is certainly the way the cars work.
I just called the 18885183752 support number and the 2 3 3 options, and a nice an knowledgeable rep discussed my situation. He understood what was needed, but said that he could only elevate this to tier 2 support after he received an email from my installer listing the make, model and hard trip frequency for my inverter(s). It seems that this can no longer be done by phone call only or by the customer only.
Relative to my specific issue today, he said that as the PW2 discharged to the house it would have eventually warmed enough and lowered the frequency. But obviously 50 minutes was not enough.
Relative to my specific issue today, he said that as the PW2 discharged to the house it would have eventually warmed enough and lowered the frequency. But obviously 50 minutes was not enough.
That is not what I get from reading it. It says several things to make be believe that impacts the battery capacity temporarily and uses internal power, like the car. And hopefully not as soon as the cars. My X seems to draw when the temps go below 50F.
During winter months, a small amount of your Powerwall capacity is reserved to improve performance in cold weather. This may change your visible total capacity in the Tesla app. Rest assured, your total capacity has not changed – this small reserve is just set aside to improve performance.
And it is going to use it's power to heat itself.
To heat itself, Powerwall draws a small amount of energy, which then allows high-power charging. During a cold night, your Powerwall automatically preheats before sunrise so that maximum solar energy can be captured during the day.
Since the powerwall cannot pull from the grid when attached to a solar system, except in Stormwatch, and it preheats before sunrise, so no solar, it use its own internal power charge to do the preheat.
I wonder if this is different if Tesla is the installer. We just had our Solarglass roof installed and the Telsa lead said we needed to call tier two support and have them make the change to the gateway if we needed the inverter frequency lower. Our Delta inverters cut out at 60.5 Hz. So I was going to ask for 61.5 or 62 Hz max which is within the operating range for our UPS units.
I believe it may pull from the grid for heating, but not for charging. Any power consumed that doesn't go into charging the battery is okay.
It would be nice if Tesla were more clear about how this works, and what the temperature point is that allows solar charging.
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