Cube Battery SOC Station powered by ESPHome

Readme.md

Cube Battery SOC Station powered by ESPHome

Bike

https://www.cube.eu/de-de/cube-trike-family-hybrid-750-swampgrey-n-reflex/789520

Problems

• Battery from Bosch, required to be removed for charging
• Charger does not allow smart control and always charges to 100%

Goal

• Control when to charge
• Control target SOC (ex. 80%) to enhance battery lifetime
• Cut power to charger when done for safety reasons

Hardware

• D1Mini ESP32
• Push Button
• Switch
• Luminosity sensor
• Smart power socket

Tools

• ESPHome
• Home Assistant
• 3D Printer

Summary

The charging station needs to have following features, detect battery presence, read current SOC and toggle battery saving mode. Using ESPHome, we can connect a push button to detect the battery, a simple switch to choose the mode and a carefully placed luminosity sensor wih a resistance dividor to get the number of LEDs turned on. There are 5 LEDs which indicate the rough SOC in 20% steps. Using the analog input of the ESP32, we convert the raw signal, combined with the battery presence, to a SOC and expose it as sensors to Home Assistant. In Home Assistant, we implement 2 scripts to turn on the power socket with the charger when a battery is detected and turn off the charger when the battery reached our desired SOC.

Photos

Battery

Connector and LEDs for current battery charge.

Charging Station

See here for 3D printing.

https://www.thingiverse.com/thing:6999548/files

Home Assistant

Available sensors exposed from ESPHome.

Typical charging session to 100%.

automations.yaml

alias: Cube SOC done charging
triggers:
  - type: turned_on
    device_id: 137b6ca5456e78a0320f59f660f7181d
    entity_id: 93b53df07e8017ee35c00f4327f40b05
    domain: binary_sensor
    trigger: device
    for:
      hours: 0
      minutes: 0
      seconds: 10
conditions: []
actions:
  - type: turn_off
    device_id: 348d7d46f72e10dde140eb8c3d38ed5b
    entity_id: a8bd86f0cbaf0f62d835fe849a2322cb
    domain: light
  - type: turn_off
    device_id: 348d7d46f72e10dde140eb8c3d38ed5b
    entity_id: d2c59626a91f45fb8bb42c5658f926c2
    domain: switch
mode: single
---
alias: Cube SOC ready for charging
triggers:
  - type: present
    device_id: 137b6ca5456e78a0320f59f660f7181d
    entity_id: e8809995f9df4b5b4b5b64caa0d80202
    domain: binary_sensor
    trigger: device
    for:
      hours: 0
      minutes: 0
      seconds: 10
conditions: []
actions:
  - type: turn_on
    device_id: 348d7d46f72e10dde140eb8c3d38ed5b
    entity_id: a8bd86f0cbaf0f62d835fe849a2322cb
    domain: light
    flash: long
  - type: turn_on
    device_id: 348d7d46f72e10dde140eb8c3d38ed5b
    entity_id: d2c59626a91f45fb8bb42c5658f926c2
    domain: switch
  - delay:
      hours: 0
      minutes: 0
      seconds: 20
      milliseconds: 0
  - type: turn_on
    device_id: 348d7d46f72e10dde140eb8c3d38ed5b
    entity_id: a8bd86f0cbaf0f62d835fe849a2322cb
    domain: light
mode: single

esphome-cube-battery-soc.yaml

esphome:
  name: cube-battery-soc
  friendly_name: Cube Battery SOC

esp8266:
  board: d1_mini

# Enable logging
logger:
  level: INFO

# Enable Home Assistant API
api:
  encryption:
    key: "<redacted>"

ota:
  - platform: esphome
    password: "<redacted>"

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

  # Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: "Cube-Battery-Soc"
    password: "<redacted>"

captive_portal:

# Depends on the build and most probably require adjustments
globals:
  - id: threshold_1_bar
    type: float
    restore_value: no
    initial_value: '0.08' 
  - id: threshold_2_bar
    type: float
    restore_value: no
    initial_value: '0.2' 
  - id: threshold_3_bar
    type: float
    restore_value: no
    initial_value: '0.4' 
  - id: threshold_4_bar
    type: float
    restore_value: no
    initial_value: '0.8' 
  - id: threshold_5_bar
    type: float
    restore_value: no
    initial_value: '0.925' 

sensor:
  - platform: adc
    pin: A0
    id: raw
    name: "RAW"
    update_interval: 100ms  # 10Hz (every 100ms)
    on_value:
      - lambda: |-
          ESP_LOGD("Raw Sensor", "Value changed to: %f", x);
    filters:
      - sliding_window_moving_average:
          window_size: 40
          send_every: 10
          send_first_at: 10
      - skip_initial: 4
  
  - platform: template
    id: level
    name: "Level"
    device_class: battery
    unit_of_measurement: "%"
    update_interval: 1s
    lambda: |-
      if (!id(battery_presence).state) return {};
      else if (id(raw).state > id(threshold_5_bar)) return 100.0;
      else if (id(raw).state > id(threshold_4_bar)) return 80.0;
      else if (id(raw).state > id(threshold_3_bar)) return 60.0;
      else if (id(raw).state > id(threshold_2_bar)) return 40.0;
      else if (id(raw).state > id(threshold_1_bar)) return 20.0;
      return 0.0;
    on_value:
      - lambda: |-
          ESP_LOGD("Level", "Battery level changed to: %f\%", x);

binary_sensor:
  - platform: template
    id: charged
    name: "Charged"
    lambda: |-
      return id(battery_presence).state && ((id(level).state == 80.0 && id(lifetime_optimisation).state) || (id(level).state == 100.0 && !id(lifetime_optimisation).state));
    filters: 
      - delayed_on: 3s
    on_state:
      - lambda: |-
          ESP_LOGI("Battery charge", "Battery is %s", x ? "charged" : "not charged");

  - platform: template
    id: charging
    name: "Charging"
    device_class: battery_charging
    lambda: |-
      return id(battery_presence).state && id(raw).state > id(threshold_1_bar);
    on_state:
      - lambda: |-
          ESP_LOGI("Battery charging", "Battery is %s", x ? "charging" : "not charging");

  - platform: gpio
    pin:
      number: D5
      mode: INPUT_PULLUP
    id: lifetime_optimisation # Target for SOC: ON=80%, OFF=100%
    name: "Lifetime optimisation"
    on_state:
      - lambda: |-
          ESP_LOGI("SOC mode", "Charge until %s", x ? "80\%" : "100\%");

  - platform: gpio
    pin:
      number: D6
      mode: INPUT_PULLUP
    name: "Presence"
    id: battery_presence
    device_class: presence
    filters:
      - invert:
    on_state:
      - lambda: |-
          ESP_LOGI("Presence", "Battery is %s", x ? "present" : "not present");

switch:
  - platform: gpio
    id: add_gnd_0
    pin: D0
    restore_mode: ALWAYS_OFF
  - platform: gpio
    id: add_gnd_1
    pin: D7
    restore_mode: ALWAYS_OFF
  - platform: gpio
    id: add_gnd_2
    pin: D8
    restore_mode: ALWAYS_OFF