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Can Powerwall be charged from grid in backup-only mode?

Dboy

Member
Mar 25, 2020
7
2
SF Bay Area
As I know Powerwall can not be charged from the grid when combining with solar. But it can be charged from the grid when you set to "storm watch" mode. I think the storm is a critical condition so that the utility allows Powerwall to be charged from the gird to keep people stay safe.
My question is whether Powerwall can be charged from the grid in "backup-only" mode.
Hope someone could give me some idea. I am going for solar with powerwall.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
10,892
12,617
Riverside Co. CA
OP, the *Key thing* here, related to your question, is this:

When you turn on storm watch mode in the app, you turn on the ABILITY for your powerwall to charge from the grid IF TESLA ACTIVATES IT IN YOUR AREA.

Thats it. Not just "when there is a storm" its "when tesla activates the feature on the powerwalls located in a geographic area. Also, once it activates, your powerwall will charge from the grid at "whatever rate you pay for electricity". If they activate stormwatch mode at 3pm, you will be charging from the grid at whatever rate you pay, at 3pm on that day.

I am sure the thinking from tesla is, "if they activated storm watch mode, and we activated this feature due to national weather report data for their area / zip, they wont care what the cost of electricity is, they will want their powerwalls filled".

Anyway, since you are asking questions about stormwatch mode and charging from the grid, its important to know that you dont get to choose when you charge with stormwatch, and it may not even activate when you think it should.
 

power.saver

Grid Specialist
Supporting Member
Mar 4, 2018
631
666
Arcadia, CA
My question is whether Powerwall can be charged from the grid in "backup-only" mode.
Hope someone could give me some idea. I am going for solar with powerwall.

No. If you have solar, you cannot charge from the grid (except during StormWatch). Being in backup mode does not change this.

If you don't have solar, then yes, charging from the grid is normal.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
10,892
12,617
Riverside Co. CA
No. If you have solar, you cannot charge from the grid (except during StormWatch). Being in backup mode does not change this.

If you don't have solar, then yes, charging from the grid is normal.

Somehow I missed this part of what OP was asking. Thanks for filling it in.

OP, as @power.saver says, with a solar install, there is no charging from grid except for storm watch, period. Mode you are operating in does not change this. If your plan is to work in backup only mode, then eventually your powerwall(s) will fill from solar. How long this takes depends on your solar install, the sun, etc.

Right now, for me (end of march), My two powerwalls fill from my 8.7 kW solar install from my normal reserve of 40% to 100% from sun up till about noon, on a typical sunny day.
 

Daniellane

Supporting Member
Supporting Member
Aug 13, 2017
2,576
3,365
Camas, Washington
As I know Powerwall can not be charged from the grid when combining with solar. But it can be charged from the grid when you set to "storm watch" mode. I think the storm is a critical condition so that the utility allows Powerwall to be charged from the gird to keep people stay safe.
My question is whether Powerwall can be charged from the grid in "backup-only" mode.
Hope someone could give me some idea. I am going for solar with powerwall.

Seems like you got your answer.
although this info may be available on Tesla’s website, I captured these screenshots from my app using the “learn more” links in settings... You may find this information useful.

AAB86F50-14C2-4DBD-80F6-2D17E63BBF8A.jpeg
47CBE5A1-4A6E-4EF9-9FC2-787BD953B0BA.jpeg
8D6965DE-2E3D-4928-AFCB-42E33C922483.jpeg
2D95B41B-747A-46F4-A2D6-2D4D8339D36D.jpeg
8D850D68-0B4B-460A-8959-6564DE31FC62.jpeg
9497403F-E0EC-4A42-B57C-240746785E1E.png
D595FEDB-35A1-4661-94AB-919008E92CE7.jpeg
23B2E8DE-12AD-464F-939F-57E793854289.png
60FA6C5B-6528-42C1-9382-07D64940951B.jpeg
24DCF7FF-2C46-435C-AC96-A580FA109EF5.jpeg
 

Dboy

Member
Mar 25, 2020
7
2
SF Bay Area
OP, the *Key thing* here, related to your question, is this:

When you turn on storm watch mode in the app, you turn on the ABILITY for your powerwall to charge from the grid IF TESLA ACTIVATES IT IN YOUR AREA.

Thats it. Not just "when there is a storm" its "when tesla activates the feature on the powerwalls located in a geographic area. Also, once it activates, your powerwall will charge from the grid at "whatever rate you pay for electricity". If they activate stormwatch mode at 3pm, you will be charging from the grid at whatever rate you pay, at 3pm on that day.

I am sure the thinking from tesla is, "if they activated storm watch mode, and we activated this feature due to national weather report data for their area / zip, they wont care what the cost of electricity is, they will want their powerwalls filled".

Anyway, since you are asking questions about stormwatch mode and charging from the grid, its important to know that you dont get to choose when you charge with stormwatch, and it may not even activate when you think it should.

Thanks for your information. It is somewhat surprising that Tesla "control" the storm-watch trigger. I thought the APP gets the storm information or alert from the third party weather provider through API, then triggers the powerwall to go into the storm-watch mode.
 

Dboy

Member
Mar 25, 2020
7
2
SF Bay Area
Seems like you got your answer.
although this info may be available on Tesla’s website, I captured these screenshots from my app using the “learn more” links in settings... You may find this information useful.

View attachment 528001 View attachment 528002 View attachment 528003 View attachment 528004 View attachment 528005 View attachment 528006 View attachment 528007 View attachment 528008 View attachment 528009 View attachment 528010
It is so detail. Thanks!
 
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gpez

Member
Apr 25, 2019
737
606
USA
Thanks for your information. It is somewhat surprising that Tesla "control" the storm-watch trigger. I thought the APP gets the storm information or alert from the third party weather provider through API, then triggers the powerwall to go into the storm-watch mode.

Tesla has be unimpressively vague on the details of how Storm Watch is triggered. Some here have speculated that it is based of NWS alerts and perhaps augmented by some manual action (say for an earthquake or the "public safety power shutoffs" in California over the summer). That makes a lot of sense but I'm always hesitant to assume something is built the way I would build it.

Personally I have never seen my Storm Watch triggered despite it being enabled and having multiple storms that have triggered it for others that are in the same county. Tesla T1 support insisted that everything was working fine and SW is only triggered for "severe" events - when pressed to define what "severe" was or wasn't the T1 agent couldn't. After the winter storm we got here in January knocked out power to tens of thousands of homes with nary a peep from SW I escalated to T2 (Powerwall worked great for us though and luckily was mostly charged). After nearly 8 weeks they finally got back to me and said there was a bug in the previous versions of the PW firmware and everything should be working now. I'm going to keep my eye out during the next storm.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
10,892
12,617
Riverside Co. CA
Tesla has be unimpressively vague on the details of how Storm Watch is triggered. Some here have speculated that it is based of NWS alerts and perhaps augmented by some manual action (say for an earthquake or the "public safety power shutoffs" in California over the summer). That makes a lot of sense but I'm always hesitant to assume something is built the way I would build it.

Personally I have never seen my Storm Watch triggered despite it being enabled and having multiple storms that have triggered it for others that are in the same county. Tesla T1 support insisted that everything was working fine and SW is only triggered for "severe" events - when pressed to define what "severe" was or wasn't the T1 agent couldn't. After the winter storm we got here in January knocked out power to tens of thousands of homes with nary a peep from SW I escalated to T2 (Powerwall worked great for us though and luckily was mostly charged). After nearly 8 weeks they finally got back to me and said there was a bug in the previous versions of the PW firmware and everything should be working now. I'm going to keep my eye out during the next storm.

Just for reference, I have had my stormwatch activate maybe 3-4 times since install in the beginning of january of this year, all for "wind" events for the county I am in. Kinda surprised me, actually, as I didnt know there were so many alerts for my area that were severe enough to trigger this. Each one was reported as a "severe wind" in the weather app I use for my phone (dark sky), so they were "official" alerts from somewhere, likely the NWS, but I dont follow the NWS closely directly.

I am a native southern californian, so in general, we dont pay that close attention to weather (lol) except for when the Power safety shutdown stuff started happening.
 
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Dboy

Member
Mar 25, 2020
7
2
SF Bay Area
Just for reference, I have had my stormwatch activate maybe 3-4 times since install in the beginning of january of this year, all for "wind" events for the county I am in. Kinda surprised me, actually, as I didnt know there were so many alerts for my area that were severe enough to trigger this. Each one was reported as a "severe wind" in the weather app I use for my phone (dark sky), so they were "official" alerts from somewhere, likely the NWS, but I dont follow the NWS closely directly.

I am a native southern californian, so in general, we dont pay that close attention to weather (lol) except for when the Power safety shutdown stuff started happening.

You are right! I am also curious whether PW will trigger the storm-watch mode when PSPS coming. We will see in this summer.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
10,892
12,617
Riverside Co. CA
You are right! I am also curious whether PW will trigger the storm-watch mode when PSPS coming. We will see in this summer.

If it doesnt (if tesla doesnt trigger stormwatch mode for users who are in PSPS areas) they are going to have a TON of very (very very very) upset people RIGHT in their back yard in Nor. Cal. I am fairly certain that if your house with a powerwall is in an area that PGE announces a PSPS for, your powerwall would trigger the stormwatch mode.

Now, keep in mind that, if they trigger it during the day before (which is normal), you could possibly be charging up at full price TOU rates. Also, I think if you stop it from charging during stormwatch mode to start it "later when its cheaper", I dont think it re starts back up charging from the grid at that later time... but someone who did that would have to verify.

I think @aesculus might have done that once but I may also be mis remembering it.
 

aesculus

Still Trying to Figure This All Out
May 31, 2015
4,533
2,601
Northern California
Also, I think if you stop it from charging during stormwatch mode to start it "later when its cheaper", I dont think it re starts back up charging from the grid at that later time... but someone who did that would have to verify.
Yeah. I did this twice and it worked great. But who knows if Tesla has not broken this. ;)
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
10,892
12,617
Riverside Co. CA
Yeah. I did this twice and it worked great. But who knows if Tesla has not broken this. ;)

Just to clarify, tesla triggered stormwatch mode on, so it was charging from the grid, it was charging during a time you did not want it to charge so you turned storm watch mode off to stop charging, then later when your electricity was cheaper you turned stormwatch mode back on, and it picked up charging from the grid again?

If thats what happened, thats very cool and not at all what I thought would happen.
 

aesculus

Still Trying to Figure This All Out
May 31, 2015
4,533
2,601
Northern California
Just to clarify, tesla triggered stormwatch mode on, so it was charging from the grid, it was charging during a time you did not want it to charge so you turned storm watch mode off to stop charging, then later when your electricity was cheaper you turned stormwatch mode back on, and it picked up charging from the grid again?

If thats what happened, thats very cool and not at all what I thought would happen.
Yep. As you stated it was charging at peak and I know the PSPS was not going to happen for at least two days so I turned it off. Then when we were a day out and in off peak I turned it back on and it charged to 100% and stayed there.

BTW we never got set with the PSPS (it got within a few miles) and once we were out of the woods I resumed normal operations even with the Storm Watch was still active. From my limited experience it seems to be set in blocks of days vs hours.
 
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EMF

Member
Dec 17, 2011
9
1
La Canada, CA
Going back to the beginning of this thread, I have to ask, why is it that "If you have solar, you cannot charge from the grid (except during StormWatch)"?

That restriction dramatically reduces the utility of Powerwalls for many of us. I live on the north side of a hill with trees to the south of the house. I have a 8 kW solar system that provides more than 50 kWh/day during 8 months of the year, but less 1.5 kWh/day from November through February. Because our Powerwalls cannot charge from the grid during these months, the system largely a waste of space and certainly a waste of money. It does not save money because we don't get enough solar power during the day to power the house through a peak rate period more than once a month. It is not a reliable backup system during the winter, when strong winds often knock out power, because it takes a month to recharge from solar after each outage. I am sure that there are others out there who have low solar power just when they need a backup system the most.

Why can't we switch from solar to the grid as the primary method for charging the Powerwalls except when a storm is coming? It seems unlikely that this is a true hardware or software design limitation, because the system can switch from solar to grid for Stormwatch. Is this a requirement imposed by some regulatory restrictions, or simply a very flawed engineering decision? Does anyone know the answer?
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
10,892
12,617
Riverside Co. CA
Going back to the beginning of this thread, I have to ask, why is it that "If you have solar, you cannot charge from the grid (except during StormWatch)"?

That restriction dramatically reduces the utility of Powerwalls for many of us. I live on the north side of a hill with trees to the south of the house. I have a 8 kW solar system that provides more than 50 kWh/day during 8 months of the year, but less 1.5 kWh/day from November through February. Because our Powerwalls cannot charge from the grid during these months, the system largely a waste of space and certainly a waste of money. It does not save money because we don't get enough solar power during the day to power the house through a peak rate period more than once a month. It is not a reliable backup system during the winter, when strong winds often knock out power, because it takes a month to recharge from solar after each outage. I am sure that there are others out there who have low solar power just when they need a backup system the most.

Why can't we switch from solar to the grid as the primary method for charging the Powerwalls except when a storm is coming? It seems unlikely that this is a true hardware or software design limitation, because the system can switch from solar to grid for Stormwatch. Is this a requirement imposed by some regulatory restrictions, or simply a very flawed engineering decision? Does anyone know the answer?

No, its not a hardware restriction, it seems to be imposed by tesla to retain the ability for people to take the income tax credit.
 

EMF

Member
Dec 17, 2011
9
1
La Canada, CA
@jjrandorin: Interesting. Do you know why being able to switch from solar to grid for 20 or 30 minutes each day to charge the powerwall would affect one's ability to get a income tax credit? If so, how does Stormwatch get around this restriction? There is probably a thread on this somewhere here, but I haven't found it. Thanks!
 

getakey

Active Member
Jan 28, 2020
1,452
475
95762
@jjrandorin: Interesting. Do you know why being able to switch from solar to grid for 20 or 30 minutes each day to charge the powerwall would affect one's ability to get a income tax credit? If so, how does Stormwatch get around this restriction? There is probably a thread on this somewhere here, but I haven't found it. Thanks!

It's the way the Credit law was written.
 

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