EV Smart Charging

The EV Smart Charging integration will automatically charge the electric vehicle (EV) when the electricity price is the lowest. The integration requires the Nordpool integration.

The integration calculates the set of hours that will give the lowest price, by default restricted to a continuous set. This calculation is done when the electricity prices for tomorrow is available (typically between shortly after 13:00 CET/CEST and midnight) or when the time of the day is before the configured charge completion time. When the automatic charging has started, changes of settings will not have any effect.

Requirements

• The Nordpool integration.
• Home Assistant version 2022.7 or newer.

Features

• Automatic EV charging control based on electrity prices from the Nordpool integration.
• Configuraton of the latest time of the day when the charging should be completed, and the earliest time the charging can start.
• Selection of preference between one continuous charging session or several (possibly more price optimized) non-continuous charging sessions.
• Optional setting of minimum SOC level that should be reached indepently of the electrity price.
• Optional setting to only charge when the electricty price is lower than a specified level (will be ignored if needed by the minimum SOC setting).
• Optional possibility to provide information to the integration about when the EV is connected to the charger.
• Optional possibility to keep the charger on after completed charging, to enable preconditioning before departure, i.e., preheating/cooling can be done from the power grid instead of the battery.
• Service calls to dynamically control all configuation parameters that affect charging.
• Automatically detects and connects to the integrations Volkswagen We Connect ID and OCPP. Connnections to other EV and charger integrations can be configured manually.

Installation

HACS

1. In Home Assistant go to HACS -> Integrations. Click on the three dots in the upper-right corner and select "Custom repositories". Paste the URL ev_smart_charging into the Repository field. In Category select Integration. Click on ADD.
2. In Home Assistant go to HACS -> Integrations. Click on "+ Explore & Download Repositories" and search for "EV Smart Charging".
3. In Home Assistant go to Settings -> Devices & Services -> Integrations. Click on "+ Add integration" and search for "EV Smart Charging".

Manual

1. Using the tool of choice open the folder for your Home Assistant configuration (where you find configuration.yaml).
2. If you do not have a custom_components folder there, you need to create it.
3. In the custom_components folder create a new folder called ev_smart_charging.
4. Download all the files from the custom_components/ev_smart_charging/ folder in this repository.
5. Place the files you downloaded in the new folder you created.
6. Restart Home Assistant.
7. In Home Assistant go to Settings -> Devices & Services -> Integrations. Click on "+ Add integration" and search for "EV Smart Charging".

Configuration

The configuration is done in the Home Assistant user interface.

The first form contains the entities that the integration is interacting with.

Parameter	Required	Description
Electricity price entity	Yes	The Nordpool integration sensor entity.
EV SOC entity	Yes	Entity with the car's State-of-Charge. A value between 0 and 100. Note that this entity is crucial for the integration. If live information about he SOC is not available, please carefully read the section below with more information about the EV SOC entity.
EV target SOC entity	No	Entity with the target value for the State-of-Charge. A value between 0 and 100. If not provided, 100 is assumed.
Charger control switch entity	No	If provided, the integration will directly control the charger by setting the state of this entity to 'on' or 'off'.

The second form contains parameters that affects how the charging will be performed. These parameters can be changed after intial configuration in Settings -> Devices & Services -> Integrations.

Parameter	Required	Description
Charging speed	Yes	The charging speed expressed as percent per hour. For example, if the EV has a 77 kWh battery and the charger can deliver 11 kW (3-phase 16 A), then set this parameter to 14.3 (11/77*100). If there are limitations in the charging power, it is preferred to choose a smaller number. Try and see what works for you!
Charge start time	Yes	The earliest time of the day for the charging to start. If None is selected, there will be no explicit limitation of the starting time.
Charge completion time	Yes	The lastest time of the day for charging to reach the target State-of-Charge. If None is selected, charging will be optimized using all hours with available price information.
Electricity price limit	Yes	If the apply_price_limit switch is activated, charging will not be performed during hours when the electricity price is above this limit. NOTE that this might lead to that the EV will not be charged to the target State-of-Charge. Also if the price limit is set to zero, there will be no limitations.
Minimum EV SOC	Yes	The minimum State-of-Charge that should be charged, independently of the electricity price.

Entities

Entity	Type	Description
sensor.ev_smart_charging_charging	Sensor	The state is "on" or "off". Can be used with automations to control the EV charger.
switch.ev_smart_charging_smart_charging_activated	Switch	Turns the EV Smart Charging integration on and off.
switch.ev_smart_charging_apply_price_limit	Switch	Applies the price limit, if set to a non-zero value in the configuration form.
switch.ev_smart_charging_continuous_charging_preferred	Switch	If turned on, will as basis schedule one continuous charging session. If turned off, will schedule charging on the hours with lowest electricity price, even if they are not continuous.
switch.ev_smart_charging_ev_connected	Switch	Tells the integration that the EV is connected to the charger. Is preferable controlled by automations (see example below). Can avoid problems occuring when the EV is not connected to the charger at the time the charging should start. Using it will also ensure that the sensor.ev_smart_charging_charging is set to "off" when the EV is not connected to the charger.
switch.ev_smart_charging_keep_charger_on	Switch	If "on", the sensor.ev_smart_charging_charging will not turn off after completed charge cycle. The feature is intended to enable preconditioning before departure, i.e., preheating/cooling can be done from the power grid instead of the battery. If this option is used, the feature Electricity price limit will be turned off, and vice versa. NOTE It is required that switch.ev_smart_charging_ev_connected is controlled in a proper way in order for this feature to work. Also, there is an assumption made that the EV itself will stop its charging when reaching the target SOC.
button.ev_smart_charging_manually_start_charging	Button	Manually start charging. This is totally independent of the automatic charging.
button.ev_smart_charging_manually_stop_charging	Button	Manually stop charging. This is totally independent of the automatic charging.

Configuration entities

The configuration parameters that affects how the charging will be performed are also available as configuration entities. This means they can be found grouped together in the integration's device view and that they can be controlled by service calls. After reload of the integration, or after restart of Home Assistant, the values will be set to the values set during configuration. For descriptions of each parameter, see the Configuration section above.

Entity	Type	Valid value ranges and service calls
select.ev_smart_charging_charge_start_time	Select	Valid options, "00:00", "01:00", ..., "23:00" and "None". Can be set by service call select.select_option.
select.ev_smart_charging_charge_completion_time	Select	Valid options, "00:00", "01:00", ..., "23:00" and "None". Can be set by service call select.select_option.
number.ev_smart_charging_charging_speed	Number	Valid values min=0.1, step=0.1, max=100. Can be set by service call number.set_value.
number.ev_smart_charging_electricity_price_limit	Number	Valid values min=0, step=0.01, max=10000. Can be set by service call number.set_value.
number.ev_smart_charging_minimum_ev_soc	Number	Valid values min=0, step=1, max=100. Can be set by service call number.set_value.

Sensor attributes

The sensor sensor.ev_smart_charging_charging has the following attributes.

Attribute	Description
Current price	The current price from the electricity price entity.
EV SOC	The current SOC of the electric vehicle, as reported by the EV SOC entity.
EV target SOC	The target SOC of the electric vehicle, as reported by the EV target SOC entity.
Charging is planned	true if charging is planned, otherwise false. Is set to false after charging is completed.
Charging start time	If charging is planned, the date and time when the charging will start.
Charging stop time	If charging is planned, the date and time when the charging will stop.
Charging number of hours	If charging is planned, the number of hours that charging will be done. This might be less than the number of hours between the start and stop times, if the apply_price_limit switch is activated.
Raw two days	The electricty price today and tomorrow from the electricity price entity.
Charging schedule	The calculated charging schedule. Can be used by an ApexCharts card to visulize the planned charging, see below.

Lovelace UI

ApexCharts Card can be used to create the follow type of graph. The black line shows when the automatic charging will be done.

Depending on the price unit used, modify the settings for unit, float_precision and color_threshold. For example, if the price unit SEK/kWh is used, change the follow lines in the example below.

        unit: ' SEK/kWh'

        float_precision: 2

        color_threshold:
          - value: -1
            color: cyan
          - value: 0
            color: green
          - value: 0.4
            color: orange
          - value: 1
            color: red
          - value: 2
            color: magenta
          - value: 5
            color: black

type: vertical-stack
cards:
  - type: custom:apexcharts-card
    now:
      show: true
      label: Now
      color: '#ffc0cb'
    locale: en
    header:
      show: true
      title: EV Smart Charging
      show_states: true
    graph_span: 2d
    yaxis:
      - min: ~0
        apex_config:
          forceNiceScale: true
    span:
      start: day
    apex_config:
      legend:
        show: false
      xaxis:
        labels:
          show: true
          format: HH
          rotate: -45
          rotateAlways: true
          hideOverlappingLabels: true
          style:
            fontSize: 10
            fontWeight: 10
    series:
      - entity: sensor.ev_smart_charging_charging
        name: Electricty price
        unit: ' öre/kWh'
        data_generator: >
          return entity.attributes.raw_two_days.map((entry) => { return [new
          Date(entry.start), entry.value]; });
        type: line
        float_precision: 0
        show:
          in_header: before_now
        extend_to: false
        color_threshold:
          - value: -100
            color: cyan
          - value: 0
            color: green
          - value: 40
            color: orange
          - value: 100
            color: red
          - value: 200
            color: magenta
          - value: 500
            color: black
      - entity: sensor.ev_smart_charging_charging
        name: Charging
        data_generator: >
          return entity.attributes.charging_schedule.map((entry) => { return
          [new Date(entry.start), entry.value]; });
        type: area
        color: black
        show:
          in_header: false
        extend_to: false
    experimental:
      color_threshold: true
  - type: entities
    entities:
      - entity: sensor.ev_smart_charging_charging
        name: Charging
      - entity: switch.ev_smart_charging_smart_charging_activated
        name: Smart charging activated
      - entity: switch.ev_smart_charging_apply_price_limit
        name: Apply price limit
      - entity: switch.ev_smart_charging_continuous_charging_preferred
        name: Continuous charging preferred
      - entity: switch.ev_smart_charging_keep_charger_on
        name: Keep charger on
      - entity: button.ev_smart_charging_manually_start_charging
        name: Manually start charging
      - entity: button.ev_smart_charging_manually_stop_charging
        name: Manually stop charging
    title: EV Smart Charging
    show_header_toggle: false
  - type: entity
    entity: sensor.ev_smart_charging_charging
    attribute: EV SOC
    name: EV SOC
    icon: mdi:battery-70
    unit: '%'

Integrating with EVs

EV SOC entity

If the EV SOC is not available as the state of an entity but as a state attribute, e.g. a sensor called sensor.my_ev with an attribute EV SOC, then it can be configured to be used by the following three steps.

1. Creating a Number Helper in Setting -> Devices & Services -> Helpers (for example named "SOC" that typically will create an entity input_number.soc)
2. Creating an automation that sets the value of this Number Helper with the value of the state attribute.
3. Use the Helper entity input_number.soc when providing the EV SOC entity in the configuration of this integration.

alias: EV SOC
description: ""
trigger:
  - platform: state
    entity_id:
      - sensor.my_ev
    attribute: EV SOC
condition: []
action:
  - service: input_number.set_value
    data:
      value: "{{ state_attr('sensor.my_ev', 'EV SOC') }}"
    target:
      entity_id: input_number.soc
mode: single

A lot of the functionality in this integration relies on knowing the EV SOC. However, if this information is not available, then it is still possible to use this integration to control a charger. In this case, create a Number Helper in Setting -> Devices & Services -> Helpers (for example named "SOC" that typically will create an entity input_number.soc), and then use this entity when configuring the integration. For the integration to work well, the value of the SOC should change between charging cycles. The recommended way to do this is to set the SOC value to 100 when charging is completed, and then set it to an appropriate value when starting next charging cycle.

For example, if the SOC entity is set 60, the Target SOC entity is set to 100 (or not configured) and the Charging speed parameter is set to 10, then there will be 4 hours of charging, (100-60)/10 = 4.

EV Target SOC entity

If the EV Target SOC is available as a state attribute, then a similar solution as for EV SOC above can be used.

If there is no integration that provides the EV Target SOC, one can create a Number Helper in Setting -> Devices & Services -> Helpers (for example named "Target SOC" that typically will create an entity input_number.target_soc), and then use this entity when configuring the integration.

Integrating with chargers

If your charger's integration does not provide a swicth entity that this integration can use for control, then the connection between this integration and your charger's integration can in many cases be made with automations.

Also, if information about the EV being connected to the charger is available, an automation can provide that information to the integration in order to improve the handling of the case when the car is not connected to the charger at the time charging is planned to start.

Example of automation to start charging

alias: EV Smart Charging - Start
description: ""
mode: single
trigger:
  - platform: state
    entity_id:
      - sensor.ev_smart_charging_charging
    from: "off"
    to: "on"
condition: []
action:
  - service: easee.set_circuit_dynamic_limit
    data:
      device_id: "b40f1f45d28b0891fe8d" (replace with your own device id)
      currentP1: 16 (replace with your preferred charging current)

Please replace the contents of action: with suitable contents for your charger.

Example of automation to stop charging

alias: EV Smart Charging - Stop
description: ""
mode: single
trigger:
  - platform: state
    entity_id:
      - sensor.ev_smart_charging_charging
    from: "on"
    to: "off"
condition: []
action:
  - service: easee.set_circuit_dynamic_limit
    data:
      device_id: "b40f1f45d28b0891fe8d" (replace with your own device id)
      currentP1: 0 (something below 6 to make the charging stop)

Please replace the contents of action: with suitable contents for your charger.

Example of automation to inform the integration that the EV is connected to the charger

alias: EV Smart Charging - EV connected
description: ""
trigger:
  - platform: state
    entity_id:
      - sensor.ocpp_status_connector
condition: []
action:
  - if:
      - condition: state
        entity_id: sensor.ocpp_status_connector
        state: Preparing
    then:
      - service: switch.turn_on
        data: {}
        target:
          entity_id: switch.ev_smart_charging_ev_connected
    else:
      - if:
          - condition: state
            entity_id: sensor.ocpp_status_connector
            state: Available
        then:
          - service: switch.turn_off
            data: {}
            target:
              entity_id: switch.ev_smart_charging_ev_connected
mode: single