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Gateway power switching?
- Thread starter Regnad
- Start date
The Powerwall 2 Backup Gateway has a simple 200A disconnect switch. When the Gateway computer detects that the grid parameters are out of the acceptable range, it isolates the backed up side of the switch from the grid by opening the contacts. It is that simple. At that point, the Powerwall(s) become the micro-grid master and they do what they can to keep the power stable without the grid.
When our solar/PowerWall installation is completed (today), I'm assuming there will be a small delay (as reported on the forums) before the PowerWalls begin providing power when the grid goes offline - and that we'll still need UPS for devices that need continuous power (computers, DVRs, routers, … - which reboot after even a brief power outage).
My experiences with a grid down situation, whether simulated or actual, has been seamless in all cases.
Well...... in one simulation I was stupid and switched the gateway breaker too soft and slow which caused a power wink.
No clocks need to be reset. I cannot speak for computers, NAS, routers, modems, DVR, etc as I have them on sine wave UPS backups.
I don't think I'd ever remove them from UPS. In an extended outage where the PV panels and powerwalls can't keep up with the house load and drain out, there's a delay before the ATS and generator take over.
I should also mention I run my powerwalls in "Backup-only 100%" mode.
Well...... in one simulation I was stupid and switched the gateway breaker too soft and slow which caused a power wink.
No clocks need to be reset. I cannot speak for computers, NAS, routers, modems, DVR, etc as I have them on sine wave UPS backups.
I don't think I'd ever remove them from UPS. In an extended outage where the PV panels and powerwalls can't keep up with the house load and drain out, there's a delay before the ATS and generator take over.
I should also mention I run my powerwalls in "Backup-only 100%" mode.
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Boatguy
Active Member
So the PW switching is not fast enough to prevent home electronics from seeing the drop?
There are a couple factors:
Until the gateway opens the circuit, your house and the grid are at the same level. If there is a sudden drop, that will impact devices (or if they are more sensitive to low voltages than the PW trip point).
The Powerwalls have a delay when switching modes from charging to discharging. So if they were charging when the grid dropped out, that would increase the time to start supplying power.
If there are super critical loads, then a small UPS will keep them happy during the switchover.
This matches my experience. The switch is as fast, or faster, than any other options that are within reach from a price & availability perspective, and most other options are way out of my price range (i.e. commercial solutions), or not available directly to consumers.
Also, when I've tested this with my Powerwalls (four of them), the results of the switch, and corresponding power "blip", seem to depend to some degree on the mode of the PW when the switch happens, but also the "depth" (not sure how else to describe this) of the momentary bounce can also be affected by the current home load. For instance, for one "off-grid" test the house was only using about 500watts, and solar was supplying the house and charging the Powerwall, and the switch to "off-grid" (manually induced at the home mains breaker) was not noticeable. For another test, I had both AC units running, and the house was pulling about 8kWs, the PW was in back-up mode and charging, and the switch over was very noticeable as I was in the garage and could hear the 200a contactor snap (fairly loudly) into off-grid mode, the garage ceiling lights flashed for a fraction of a second, but interestingly enough both AC units kept running.
So for me, as mentioned above, I do have my internet modem/routers/wifi and computer all on a UPS (which I had before the PW anyway, to protect from spikes and brown-outs) which will buffer this equipment from any potential switch-over related momentarily power "blip" - which will probably occur for any such solution powerful enough to power an entire home and it's AC while under load... as far as I'm aware.
Also worth mentioning, in some other threads there is some good info on using Eaton UPSs', can be small ones, as they handle frequency shifting better that most other brands, in some scenarios where the PWs are not configured ideally, and/or with some solar/inverter equipment. I've been wanting to get a couple more UPS to better configure my home network and computer power isolation and backup , so I'll probably be using the Eaton UPSs' as they seem more flexible and forgiving in Solar/Inverter environments where AC frequency shifting is in use to control loads and power routing (Grid/Home/PWs/etc), particularly in off-grid situations.
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Boatguy
Active Member
I have most of my computer equipment on UPSs and they switch very quickly. We have frequent power "blips" where the lights flash and the UPSs will briefly trigger. The problem has been with audio equipment where the power supplies in some expensive equipment have been damaged. I have PWs being installed this month and was hoping they would smooth things out, but it sounds like that is only the case if the load is low and the PWs are charging from the solar. So it looks like I'll still need small UPSs on the sensitive equipment.
Probably. The situation will still be less impact than grid level "blips" in most cases, but for sensitive equipment I still keep some UPS on them, but now they can be very small compared to the higher capacity units I used to use - I only need a minute or so of capacity (or less).
Powerwalls cannot smooth or clean grid power. You'll need either a line interactive or on-line UPS for that. Uninterruptible Power Supplies: A Guide for Average Joe's
Our solar/PowerWall installation should be completed today, waiting for PTO from the utility company to turn everything on.
I've already notified our installers I want to run some acceptance tests to verify the system will be able to operate at a full load (everything in our house running) when we switch from grid to PowerWall and PowerWall to grid, and that all of the UPS systems operate through those transitions keeping our computers/TiVo/cable modem/cable DVR/routers running without having to reboot.
I'm not expecting any problems - but want to validate this all works before giving them their final payment...
I've already notified our installers I want to run some acceptance tests to verify the system will be able to operate at a full load (everything in our house running) when we switch from grid to PowerWall and PowerWall to grid, and that all of the UPS systems operate through those transitions keeping our computers/TiVo/cable modem/cable DVR/routers running without having to reboot.
I'm not expecting any problems - but want to validate this all works before giving them their final payment...
I did the same, and the installation lead for my install called me out to the garage and we ran through the tests together while I had the app on my phone open and running, to make sure I could see everything that was happening, and to see for myself the switch over of the house load. I specifically cranked up the AC units before he flipped the switch just to make sure. Good luck!
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@bob_p be sure to run the test when solar production is high and house load is low when the Powerwalls are full as well. This is especially important if you have an oversized PV compared to your Powerwalls as if the PV is producing more than the Powerwalls can store (either because the PV has exceeded the PW inverter limits or the PW is full).
mikemillar
Member
If you want to test the backup response, just pull the main fuse in the gateway (mine is a Gateway 2). Alternatively switch off the switch on the side of the Powerwall. I'm not sure what the difference is. Pronbably fulling the fuse simulates a grid outage. Switching off the Powerwall means that the Gateway is still comnnected to and powered by the grid. Mine changes over seamlessly and even my NAS and computers don't shut down. You'll hear a clunk from the main contactor after a few seconds. When you put the fuse back it takes quite a while, maybe half a minute before the main contractor resets with another clunk, so don't be alarmed if nothing happens for a while.
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