Time to cut over after grid is lost

[Moonwick]

Those of you who have Powerwall 2s, can you give me an idea of how long it takes for them to start providing backup power after grid power is lost? I realize that it isn't instantaneous since there's time required to flip the ATS, but I'm wondering if it's under a second or if it's more on the order of multiple seconds.

Thank you!

 

[aesculus]

From my huge 2 event experience I would say it's on the order of a second or less. For sensitive devices like computers you may need a UPS but most devices will never sense the cut over.

EDIT: The return to grid power did take a number of seconds (minutes) from my experience but this should not be a big deal.

 

[patrick40363]

It is very fast. I got rid of my UPS backups as they were no longer needed.

 

[reddy]

Both of our power failures occurred during daylight hours when solar was producing, so we couldn’t even tell the grid was down.

 

[jjrandorin]

Those of you who have Powerwall 2s, can you give me an idea of how long it takes for them to start providing backup power after grid power is lost? I realize that it isn't instantaneous since there's time required to flip the ATS, but I'm wondering if it's under a second or if it's more on the order of multiple seconds.

Thank you!

Grid off to powerwall providing power is under a second. Its not long enough for lights to go off... but as said sensitive electronics may see a hiccup and reboot. When grid comes back up, it can take around 5 minutes for the powerwall to sync back to the grid but that is seamless to you because there is no interruption in power.

Its really very fast, and basically automatic. Not quite instant but very close to that.

 

[bmah]

There are a couple of different scenarios. If your Powerwalls are already providing power to your house and you lose your grid connection, there's no interruption in power at all.

If your house is only drawing power from the grid, there will be a very short interruption in electricity (less than a second), where your lights might blink. Computers or other electronics will likely reboot. It's this situation where UPSs are still useful in your house...but they only need to power your computers, network equipment, etc. for a fraction of a second until the Powerwall batteries take over.

Bruce.

 

[Moonwick]

It is very fast. I got rid of my UPS backups as they were no longer needed.

Wow! I wasn't expecting anything quite as good as UPS response time, but even close to that is impressive.

There are a couple of different scenarios. If your Powerwalls are already providing power to your house and you lose your grid connection, there's no interruption in power at all.

If your house is only drawing power from the grid, there will be a very short interruption in electricity (less than a second), where your lights might blink. Computers or other electronics will likely reboot. It's this situation where UPSs are still useful in your house...but they only need to power your computers, network equipment, etc. for a fraction of a second until the Powerwall batteries take over.

Thank you! That's an interesting detail, I suppose it takes it briefly longer for the inverter to 'wake up' when it's gone into standby.

I'm comparing the Powerwall against other energy storage systems, and the Powerwall sounds like it compares very, very favorably. Thank you everyone for your replies!

 

[boaterva]

Electric devices that usually react like stove clocks and microwaves don’t know the power was out, it is that quick. I had one day a month ago when for some reason we had four five minute outages over several hours and the only reason I know about it was the record on the Tesla app.

I didn’t even notice lights blinking or any transition; only knew because the app on my phone in front of my changed to its orange outline.

Also, as noted you do (still) want UPS backup on your computers and the like but it’s great that when the batteries next need replacing for your UPSes you can instead get a less expensive new UPS that runs for say 10 minutes and not replacement batteries for the current ones.

I have a large one with extended battery pack in my home office that will run my PC, monitors, routers, wifi, etc, for over an hour. No longer needed with PWs! One advantage I hadn’t thought of.

 

[bob_p]

After running several off-grid tests, will be making a pass through our house to replace most of our UPS with surge protected power strips.

We do have a couple of large battery UPS systems, and as noted above, when those batteries need replacement will shift to smaller batteries, since we should only need power for processor-based devices for a few seconds.

 

[jrweiss98020]

As someone mentioned above, a good UPS will protect against undervoltage as well as spikes, and has a response time on the order of 10 ms (1/100 second). While the Powerwall is quick, it is probably 10x that of a UPS. I am keeping my UPSes on my computers.

 

[gpez]

In my experiences, both tests and actual grid outages, I've seen everything from milliseconds to 2+ seconds to switch over. Like @jrweiss98020 I still have my UPSs for my PC, home server, and Xbox. If you've ever had a power blip you'll know that lights will flicker and most UPSs make an audible "click" as they react to the very short power interruption. It's almost the exact same experience when the grid drops and the Powerwall takes over - my UPSs all "click" and the lights flicker just a little bit. It's enough for me to keep the UPSs.

One other reason for me to keep the UPSs is that I had issues in the past with breakers tripping when the Powerwall takes over. Found out that this was likely due to the sensitive AFCI/GFCI circuitry in the breakers not being happy with the high Powerwall frequency. After fixing the frequency I haven't had any issues with the breakers however if there is an outage and a breaker does trip I don't want my sensitive electronics to drop. If that happens I just need a few minutes so a small UPS is plenty.

 

[cwied]

One thing to note is that real power outages aren't necessarily like flipping a switch. There may be periods of unreliable power before the Powerwalls decide to isolate from the grid. In the one real power outage I've had since getting the Powerwalls this was the case. All the clocks in the house needed to be reset after the outage. Note that for several days before the outage, my solar inverters had been shutting down intermittently due to issues with the power.

 

[schrodarkian]

You would be wise to have UPS’s for sensitive electronics. I’ve had multiple outages with Powerwalls, and the iMac usually reboots. Otherwise, you might not even notice the interruptions.

 

[jboy210]

One thing to note is that real power outages aren't necessarily like flipping a switch. There may be periods of unreliable power before the Powerwalls decide to isolate from the grid. In the one real power outage I've had since getting the Powerwalls this was the case. All the clocks in the house needed to be reset after the outage. Note that for several days before the outage, my solar inverters had been shutting down intermittently due to issues with the power.

That is a concern of mine. We just had another power outage (approx 4,000 PG&E customers) this week. It was sort of a rolling affair with a slight flicker, and then perfect for 10 seconds, then another flicker, and then perfect for 10 seconds, and final a loud thud in the distance and no power. Lasted about 3 hours for us, and 12 hours for people in next neighborhood 200 feet away.

So I am keeping UPS units on my NAS, comm gear, and computers even with PW. I see it as belt and suspenders insurance.

 

[jjrandorin]

That is a concern of mine. We just had another power outage (approx 4,000 PG&E customers) this week. It was sort of a rolling affair with a slight flicker, and then perfect for 10 seconds, then another flicker, and then perfect for 10 seconds, and final a loud thud in the distance and no power. Lasted about 3 hours for us, and 12 hours for people in next neighborhood 200 feet away.

So I am keeping UPS units on my NAS, comm gear, and computers even with PW. I see it as belt and suspenders insurance.

boy, I am betting your install cant get here soon enough for you and your family... what a mess up there!

 

[jboy210]

boy, I am betting your install cant get here soon enough for you and your family... what a mess up there!

Supposed to start March 1. PW install March 3. We can hardly wait. Like kids at Christmas. Except we have to play Santa to Elon and send him a big check.

 

[dortor4ev]

response time is immediate or fractional seconds - you'd be hard pressed to notice.

 

[Chuq]

There are a couple of different scenarios.

That explains something that had confused me...

On a recent episode of Fully Charged, Robert had just had his Powerwall installed at his house and they did a live demonstration of the grid being cut off. The lights went out, and then 5 seconds later they came back on.

On another recent episode of Tesla Time News, Zac and Jesse were recording an episode, and at one point they both paused, said that they heard a noise from outside - it seems that a nearby tree had fallen over, taken out a powerline, Zac's 4x Powerwalls had kicked in and all the studio equipment (lights, cameras) continued going as normal. Zero interruptions apart from the fact that obviously they wanted to talk about the Powerwalls and how awesome they are

I thought it may have been related to UK vs USA regulations but it could also have been the different scenarios as you suggested.

 

[jrweiss98020]

response time is immediate or fractional seconds - you'd be hard pressed to notice.

But your computer will!

 

[dortor4ev]

But your computer will!

if it's a lap top - not so much it will just use it's battery - and even my desktop's don't notice too much - it's pretty quick.