Powerwall - storm watch and car charging

[Fat Wolfie]

We had our Powerwall and solar installed in late January this year, and are very happy indeed.

We are able to charge the Powerwall and car (Model Y) off peak at the same time - ie - the grid feeds both the Powerwall and car simultaneously (as opposed to grid-battery-car)

Today we have had a Storm Watch warning, which has of course meant the Powerwall has topped itself up to 100% using peak rate electric (we got very little solar today). I am fine with this, we have a warning of a likely grid outage caused by the weather so we may or may not end up running off grid sometime in the next 24 hours.

I had the car plugged in, set at 30amps, scheduled to start to charge at 12.30. I don’t actually need to charge, but was planning to take the car from 50% to 80% tonight.

I have stopped the car charging from happening as I’m not sure what would happen in the event of a power outage and the Powerwall being full.

What I am curious to know is if we are in power outage conditions, would the car charger (a BP Pulse, acting as a dumb charger as there’s no internet in the garage) still charge the car and draw from the Powerwall until the Powerwall reserve is reached, or would the car not charge at all as there is no grid feed to the charger?

Be interested to learn for the future

 

[Burley]

How has your Powerwall been set up? Ours has been installed with the Zappi upstream of the PW so if there is a Grid outage, the charger doesn't draw from the PW, as its the Grid side of the backup gateway. Decided to go that way so we get the most time running the house from the PW if the grid is down for a while.

 

[MorrisonHiker]

Years ago, we were in a multi-day outage due to a blizzard and were concerned about the EVs draining the Powerwalls too much. We tweeted Tesla about the issue and they eventually added functionality to the app which allows you to configure how much of the Powerwall energy can be used for EV charging.

In the UK, do you have a setting for EV Charging in the app?

 

[Dilly]

Years ago, we were in a multi-day outage due to a blizzard and were concerned about the EVs draining the Powerwalls too much. We tweeted Tesla about the issue and they eventually added functionality to the app which allows you to configure how much of the Powerwall energy can be used for EV charging.

In the UK, do you have a setting for EV Charging in the app?
View attachment 915730

Yes, we have this in the U.K. The OP should be able to set his to suit his needs

 

[Fat Wolfie]

Thanks all for replies.

@MorrisonHiker @Dilly I’ve had a look in the app and can’t see the screen referred to. The car is currently plugged in (but not charging) so would I need to unplug to be able to access this setting? Or can you give me a steer, please as to where the screen is in the app. Thanks.

 

[KennethS]

Thanks all for replies.

@MorrisonHiker @Dilly I’ve had a look in the app and can’t see the screen referred to. The car is currently plugged in (but not charging) so would I need to unplug to be able to access this setting? Or can you give me a steer, please as to where the screen is in the app. Thanks.

In the iOS app it’s under Settings and then EV Charging.

 

[WannabeOwner]

I’ve had a look in the app and can’t see the screen referred to

From memory someone else reported that, they called Tesla and they had a fiddle and it fixed the problem.

 

[Dilly]

This is from my app V4.18.1 (the latest) though it’s been there for some while
hope you get it sorted
I use a Zappi charger so it’s not Tesla charger related

 

[Fat Wolfie]

@Dilly thanks for that. I don't have any updates available for the app, which is 4.18.0-1607 and the feature you e shown me doesn’t seem to be present.

@upgraded has suggested that I might need to call Tesla support to get it sorted, so I’ll get on with that tomorrow…

meantime here’s the screenshot of the Powerwall settings page, with EV Charging conspicuous by its absence..

 

[Dilly]

@Dilly thanks for that. I don't have any updates available for the app, which is 4.18.0-1607 and the feature you e shown me doesn’t seem to be present.

@upgraded has suggested that I might need to call Tesla support to get it sorted, so I’ll get on with that tomorrow…

meantime here’s the screenshot of the Powerwall settings page, with EV Charging conspicuous by its absence..

View attachment 916135

@Fat Wolfie I can’t understand why it’s not there. I can’t remember when the feature was added but it’s some while ago. Certainly in the version you have.
I’d go with the phone call.
Hope it’s not a delete and reinstall job!

 

[MorrisonHiker]

When you had your Powerwalls installed, did they set them up to backup loads such as EV charging? If not, that could be why you don't see the option. If you do a test and manually turn off the grid and try charging, is your Powerwall able to charge your vehicle?

 

[Dilly]

@Fat Wolfie is your charger included in the backup side of the PW gateway or is it excluded.
That May have a bearing.
Just clutching at straws…

 

[Fat Wolfie]

I’m not sure about how exactly the Powerwall was set up, I’ll get in touch with the installation co next week and see what they say.

 

[phil4]

Excuse the interruption... hoping get powerwalls installed this year. Is there some special wiring done to have the PW allow "10% EV charging"? I've got two chargers, a dumb Tesla one wired into the house CU, and a Zappi wired direct to the meter. I'd be quite happy with one powered by the PW, and one not. but Unsure how they "isolate" the charger usage. Any ideas? Or is this some magic the installer does?

 

[Dilly]

Excuse the interruption... hoping get powerwalls installed this year. Is there some special wiring done to have the PW allow "10% EV charging"? I've got two chargers, a dumb Tesla one wired into the house CU, and a Zappi wired direct to the meter. I'd be quite happy with one powered by the PW, and one not. but Unsure how they "isolate" the charger usage. Any ideas? Or is this some magic the installer does?

A charger and anything else for that matter, can be wired outside of the Powerwall backup. the installer can do that.
With everything on the backup side, If charging overnight on cheap rate, Powerwall settings will use the grid. Daytime, draw will be from the Powerwall.

 

[WannabeOwner]

Unsure how they "isolate" the charger usage

have you got [now or in future] any PV (that you would want to be able to into either one or both car chargers ... as well as the PowerWall

That would likely complicate things!

 

[phil4]

have you got [now or in future] any PV (that you would want to be able to into either one or both car chargers ... as well as the PowerWall

That would likely complicate things!

That'll be fun then... as at the moment, the PV goes into it's own CU, then to a henley block after the meter. The charger and house CU all feed from that henley block.

Thus at the moment, and PV provides power to house and car charger when it's generated. That's obviously both chargers.

The "seperate" charger is a Zappi, with numerous CT clamps and so uses the "is there grid excess" to charge like it did today.

I fully expect some fun, however as the installer of the PV and Zappi knew there would be a PW coming, and indeed has run all the leads, and fuses in that new CU for the PW... you'd hope it'd all work together in some fashion

 

[WannabeOwner]

you'd hope it'd all work together in some fashion

Unfortunately there are a lot of variabilities ...

If all the PV, PowerWalls and Chargers are "joined" then PV can fill up PowerWall and then Zappi can spill excess to the car. But that requires you've plugged the right car into the Zappi ...

... and it would mean that if you charge the car (daytime, or during storm) that will drain the PowerWall (there are some settings in APP that can help with that) ... or you can deliberately set the RESERVE on PowerWall to whatever its current SoC is - which will prevent further PowerWall drain. But that's maybe OK for charging during the day ... not so good for charging overnight when it happens that Storm Watch has activated and you are fast asleep.

Storm Mode becoming SET is pretty rare in my experience ... once or twice a year, and the weather forecast is wall-to-wall doom-and-gloom of course - you'd struggle to miss it! So you could deliberately disconnect and not charge the cars at that time without too much inconvenience - and you'd probably want to make sure that both cars were fully charged before then, in preparation for the storm ...

So Storm Mode discharge may not be that big of a deal in practice? Just disconnect the car during a storm.

If one charger is "outside" the CU then it will only charge from grid, it won't drain the PowerWall, but it cannot be used to dump excess PV to the car (that I know of). Maybe having the Zappi dump PV to car and the other charger not - is a suitable solution? Wouldn't work for me, at peak summer I have 15kW of PV so if I want to use it all I have to charge PowerWall and both cars simultaneously to avoid export ...

I've got a Zappi, bought specifically as second car charger to spill over excess PV to the car, but in practice I would never have the right car parked at the right charger so instead I have some lash-up code using API to detect when PowerWall is approaching full / at 100%, and PV is producing more than house is using, when that happens it starts one (or both) cars charging. Having everything "Tesla" makes that easier at present.

I reckon what is needed includes:

1. Charge car when excess PV available (Zappi Eco+ mode I think)

2. Charge the car overnight on Off Peak - I don't know if Eco+ is incompatible with that requirement, and whether it is necessary to use Schedule from Zappi rather than the car). Personally I prefer the car scheduler - it will start at the appropriate time regardless of internet connectivity etc.. I then use one (of the many) APPs available which will STOP the charge when Off Peak ends (which Tesla doesn't currently do).

3. Charge the car during the day "adhoc". If a mate rocks up and plugs in I expect it to start charging - not to have to use the Zappi APP to override. I reckon that will be incompatible with Eco+ (that needs confirmation).

4. Turn on car Climate shortly before departure - again I think that is going to want both Car APP and Zappi APP to enable that. For me having to do 2-apps is "too much". My way is to have both car chargers "always live" and leave it to the Car to say "Start Charge" or "Climate on" and draw power from the grid (which might be the PowerWall)

Others do not want the car to use grid during the day under any circumstances (e.g. for Climate prior to departure) because their Off Peak tariff makes it cheaper to use Car Battery (charged during Off Peak). If I'm on a 100% charge departure, for max range, I definitely want Grid Power for Climate before I set off ...

So, at that point, it is all getting way more complicated than "you'd hope it'd all work together in some fashion"

So "depends what you want" applies I think ...

 

[phil4]

Well I need something to occupy my spare time

And yes, I can see your point, it doesn't automatically do everything for everyone. Thank your for you explanation.

 

[Fat Wolfie]

I’ve now heard back from the installer.

he says that the way my system is set up with my dumb charger means that in the event of a power outage the car, if plugged in, will take from the Powerwall as it effectively sees the charger as part of the house load.

As my current set up works so well for me OTHER than in the event that there is a power outage AND I am charging the car at the same time, I’m happy enough with the way it’s all set up. I don’t plan on changing the charger for a Tesla or Zappi, and somehow getting internet connection to the garage.

It was more a case of knowing so I could take appropriate action (like unplugging the car under storm watch conditions) if needs be. I can live with the risk that an unplanned power outage could mean the Powerwall is down to reserve by the morning if I’m also charging the car.

Thanks all for the input