How does HA control the Powerwall?

[wyx087]

Can I ask a few questions whilst deciding on my home battery install?

Powerwall 3 looks like a great product, Tesla's expertise on BMS and its thermal management make it a great candidate for my install outdoors. However, looking into Tesla app -> Discover -> Powerwall demo there is so little configurable settings it doesn't feel like I'm buying a battery I can control and automate.

Here's a starter list of controls I need for my home battery, can I do this in HA via this Tesla custom integration?

1. Force battery to stop load balancing and go idle/inactive/hold.
2. Force battery to start charging on my command at power level of my choosing
3. Force battery to discharge on my command at power level of my choosing
4. Set overnight charge limit to leave space for solar excess.

The controls exposed by this Tesla custom integration is bizarre, I can't wrap my head around what each one does and how to achieve what I want to do.

My other cheaper battery candidate can easily do all those with local control (Tesla control is via cloud isn't it?). But it need some weather shielding and people report BMS isn't good at reporting SoC. So as a physical product it's worse.

Also, when you open the Tesla app to look at Powerwall, presumably it opens to your car and as a result the car will wake up?

Thanks very much

[skipishere]

I have a Powerwall 2 (so this may not be 100% correct for Powerwall 3) and am using the unofficial API:

1. You can change the battery from Time-Based control to Self-Powered, in this case with Self powered you won't draw from the grid unless you hit your reserve level.
2. ~ish you can set the reserve level which can force the battery to charge if set to Time-Based & Grid charging it might charge but it tries to be clever and charge up depending on your usage/solar generation (if applicable) which may not be what you want. I have an automation that will bump up the reserve level to 5% less than a set charge level that will swap the battery from Grid charging Yes to No. This is more tricking the powerwall then actually getting it to charge.
3. No~ish. If you have the rates set so the battery thinks it's worth discharging & you have Time-Based then it may discharge, but there are times when the powerwall tries to be smart and won't discharge due to usage it thinks you might use.
4. Yes - kind of explained in point 2

In terms of Local/Cloud, the official plugin with Home Assistant is Local but there are many things that (currently) can't be controlled locally (😭) which is one of the reasons this plugin exists (which uses cloud)

This is my dashboard with 2 helpers and 2 binary sensors (to make things easier)

    charge_house_battery:
      friendly_name: "Charge Powerwall from grid"
      value_template: >-
        {{ int(states('sensor.powerwall_charge')) < int(states('input_number.powerwall_charge_threshold'))
        and states('select.electric_import') == 'Off-Peak' }}
      icon_template: >-
        {% if is_state('binary_sensor.charge_house_battery','on') %} mdi:transmission-tower-import
        {% else %} mdi:transmission-tower-off
        {% endif %}
        
    discharge_house_battery:
      friendly_name: "Discharge Powerwall to grid"
      value_template: >-
        {{ int(states('sensor.powerwall_charge')) > int(states('input_number.powerwall_discharge_threshold'))
        and states('select.electric_import') == 'Peak' }}
      icon_template: >-
        {% if is_state('binary_sensor.discharge_house_battery','on') %} mdi:transmission-tower-export
        {% else %} mdi:transmission-tower-off
        {% endif %}

I'm on a time of use tariff so also have a seperate automation that changes the electric_export and electric_import based on time (which is further complicated by occasionally having Free Power time slots and Saving Sessions, which I've not included here)

Import Automation:

alias: Powerwall Import
description: ""
trigger:
  - platform: state
    entity_id:
      - binary_sensor.charge_house_battery
    id: start
    from: null
    to: "on"
  - platform: state
    entity_id:
      - select.electric_import
    from: Off-Peak
    id: stop
  - platform: state
    entity_id:
      - binary_sensor.charge_house_battery
    from: null
    to: "off"
    id: stop
  - platform: state
    entity_id:
      - select.electric_import
    from: Free
    id: stop
    to: Mid-Peak
condition: []
action:
  - choose:
      - conditions:
          - condition: trigger
            id:
              - start
        sequence:
          - service: select.select_option
            data:
              option: Time-Based Control
            target:
              entity_id: select.home_operation_mode
          - service: select.select_option
            data:
              option: "Yes"
            target:
              entity_id: select.home_grid_charging
          - service: number.set_value
            data_template:
              value: >-
                {{ states('input_number.powerwall_charge_threshold') | int - 10
                }}
            target:
              entity_id: number.home_backup_reserve
      - conditions:
          - condition: trigger
            id:
              - stop
        sequence:
          - service: select.select_option
            data:
              option: "No"
            target:
              entity_id: select.home_grid_charging
  - if:
      - condition: not
        conditions:
          - condition: state
            entity_id: select.electric_import
            state: Off-Peak
    then:
      - service: select.select_option
        data:
          option: Self-Powered
        target:
          entity_id: select.home_operation_mode
      - if:
          - condition: state
            entity_id: binary_sensor.octopus_free_power_24h
            state: "on"
        then:
          - service: number.set_value
            data:
              value: "1"
            target:
              entity_id: number.home_backup_reserve
            enabled: true
        else:
          - service: number.set_value
            data:
              value: "10"
            target:
              entity_id: number.home_backup_reserve
            enabled: true
mode: single

Export Automation

alias: Powerwall Export
description: ""
trigger:
  - platform: state
    entity_id:
      - binary_sensor.discharge_house_battery
    id: start
    to: "on"
    from: null
  - platform: state
    entity_id:
      - select.electric_export
    from: Peak
    id: stop
  - platform: state
    entity_id:
      - binary_sensor.discharge_house_battery
    id: stop
    to: "off"
    from: null
condition: []
action:
  - choose:
      - conditions:
          - condition: trigger
            id:
              - start
        sequence:
          - service: select.select_option
            data:
              option: Time-Based Control
            target:
              entity_id: select.home_operation_mode
          - service: select.select_option
            data:
              option: "Yes"
            target:
              entity_id: select.home_grid_charging
          - service: select.select_option
            data:
              option: Everything
            target:
              entity_id: select.home_energy_exports
      - conditions:
          - condition: trigger
            id:
              - stop
        sequence:
          - service: select.select_option
            data:
              option: Solar
            target:
              entity_id: select.home_energy_exports
  - if:
      - condition: not
        conditions:
          - condition: state
            entity_id: select.electric_export
            state: Peak
    then:
      - service: select.select_option
        data:
          option: "No"
        target:
          entity_id: select.home_grid_charging
      - service: select.select_option
        data:
          option: Self-Powered
        target:
          entity_id: select.home_operation_mode
mode: single

[wyx087]

Thanks so much for answering, Tesla doesn't make it easy do they.......

Normal operation, I presume (dangerous I know), regardless of time or solar mode, is battery always load balancing zero the power import/export to the grid. Only when battery is full or at backup reserve limit I would need to use the grid.

From what I can see in the app, the mode select only affects charging? Time mode try to charge when electric tariff is cheapest, always to full? Solar mode wouldn't charge based on tariff only try to self consume solar. I'd need something in the middle. Charge a little bit but leave space for solar, trying to base it on tomorrow's solar prediction.

1. You can change the battery from Time-Based control to Self-Powered, in this case with Self powered you won't draw from the grid unless you hit your reserve level.

Sorry, badly worded on my part. In this battery inactive/hold mode, I want battery to behave as though I don't have any battery, everything comes from the grid or go into the grid if solar excess.

I am also with Octopus, I'd like to activate this mode when Intelligent Octopus dispatch is turned on and starts charging the car. I'm guessing you are on Agile from "free_power_24h", this tariff is something I'd like to try in the future when I get home battery.

input_number.powerwall_charge_threshold

How well does this import automation work in your experience? Reads like it sets a lot of control commands in order for battery to charge. Can I use this sequence of commands every night to charge to my desired levels in order to leave space for solar?

Or for fixed time of use tariff, based on my guessed understanding for time vs solar mode in the app, is it easier to do following? Set time mode when cheap leccy starts. If SoC is above desired level, set to solar mode. Repeat every day.

Doesn't look like it is possible to manually set charge/discharge power levels? Powerwall 3 charges/discharges at whopping 11 kW!
Slower charging desire is for fire safety, in my mind connections wouldn't heat up if I charge at slower rate. For example, my car normally charges at reduced amp just high enough to get to my target SoC over whole cheap period.
Discharging desire is mainly for when I switch from deemed to SEG export tariff and export during grid DFS/Saving session. But I don't want to empty the battery........

Finally, does controlling powerwall contribute to the 50 command limit and affect controlling the car? Is it account limit or device limit?

[skipishere]

Normal operation is an interesting one

• Self-Powered it will attempt to use solar then battery then grid as much as possible
• Time-Based will try and save/make the most money so if grid is cheap it will use/charge on that to then discharge when it is higher to sell

If you have grid charging enabled, this will then charge up (when on Time-based) to a point where it thinks it will cover the day usage + solar generation. This is a bit interesting as it tries to predict your usage and what you might generate during the day, so won't necessarily charge to full (this is why in my automation I alter the backup reserve to force a minimum charge %)

I'm on the Octopus Flux (cheap rate from 0200 - 0500, day rate from 0500-1600 & again at 1900 - 0200, with peak rate at 1600 - 1900) so it benefits me to charge up at cheap and discharge like mad at peak. I'm also in a trial area for 12 months where we occasionally get a few hours of free* electricity (* you initially get charged for it and then in a few weeks time, a rebate is applied to zero out the cost, but you need to agree in advance to using power at the time so if you don't you end up paying for it, hopefully in the future it will be automatic/nicer)

So far the automation seems to work quite well, the biggest issue is if there is an internet or cloud outage just at the wrong moment, I probably could get away with just leaving it on Time-Based but there have been occasions where it will do the wrong thing, setting it to Self-Powered is more of a safety net (esp if I forget to amend the price in the Tesla app when we have the aforementioned free power sessions)

Doesn't look like it is possible to manually set charge/discharge power levels?

Sadly not as yet, at least not on the API we currently have, if this was available at a local level it would make my automation so much better/nicer/more stable. This is why I have the automation to switch between Self-Powered and Time-Based to attempt to trick the system into doing the desired thing.

Does controlling powerwall contribute to the 50 command limit and affect controlling the car?

I don't know, as I'm still using the unofficial legacy API. Hopefully someone else knows that answer (I did read the docs on the Fleet API a while ago around the Powerwall)

Hope that answered all the questions, happy to go into more detail if I missed any or something doesn't make sense. (It's taken me 30 mins to write this all out, so I'm sure I've made a few mistakes/missed stuff...)

[wyx087]

Thank you so much. It had been extremely helpful and important to learn controls before getting one installed. Hopefully I'll have one to use by end of August 😄 I'll "borrow" your automations.

For cloud outages, I tend to use a loop script to check status and retry after a minute or so. I did run into similar problem, for example Tesla vehicle not starting charge. But my retry scripts has never failed so far. It also allows automation to continue to run even if error stops the script.

I've also got answers on HA community, in case it helps you:
https://community.home-assistant.io/t/tesla-powerwall-controls/227228/18