CB2S + BL0937 => current measurement remains in dashboard without a load

Hardware
1

Apologies, just read that this should have been in the Configuration category.

Hi all,

Hardware: Mercator Ikuu SPLUG02 series 2. Single relay switched plug with current,power, voltage measurement.
Internal hardware: Beken CB2S, Measurement chip: BL0937 (HLW8012 equivalent).

I am confused on the issue of seeing a Current measurement even when there is no load connected. and the relay is OFF.

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Relevant portion of the code:

# Board: Generic - BK7231N (Tuya QFN32)
# Definition: definitions/boards/generic-bk7231n-qfn32-tuya/manifest.yaml

esphome:
  name: mainsswitch2
  friendly_name: MainsSwitch#2

bk72xx:
  board: cb2s

logger:

api:
  encryption:
    key: "mzAZmQ6OHX2CDwKzLu9zoNgf02G7KJJIRotabxieFf8="

ota:
  - platform: esphome

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password
  ap:
    ssid: MainsSwitch#2 Fallback Hotspot
    password: "lhMzHy6jefiD"

captive_portal:
text_sensor:
  - platform: libretiny
    version:
      name: LibreTiny Version

output:
  - platform: libretiny_pwm
    id: output_led_1
    pin: P26


What am I missing, or should I do differently?

Cheers,
DutchTuatara
light:
  - platform: monochromatic
    id: light_switch_1
    output: output_led_1

binary_sensor:
  - platform: gpio
    id: binary_switch_1
    pin:
      number: P11
      inverted: true
      mode: INPUT_PULLUP
    on_press:
      then:
        - switch.toggle: switch_1

switch:
  - platform: gpio
    id: switch_1
    name: Relay 1
    pin: P8
    on_turn_on:
      - light.turn_on: light_switch_1
    on_turn_off:
      - light.turn_off: light_switch_1

status_led:
  pin: P10

substitutions:
  voltage_divider: "767.4905739421869"
  current_resistor: "0.0010422723965338564"
  current_multiply: "1802.2626856731272"

sensor:
  - platform: hlw8012
    model: BL0937
    cf_pin:
      number: P7
      inverted: true
    cf1_pin:
      number: P6
      inverted: true
    sel_pin:
      number: P24
      inverted: true
    current:
      name: BL0937 Current
      filters:
       - multiply: ${current_multiply}
    voltage:
      name: BL0937 Voltage
    power:
      name: BL0937 Power
    energy:
      name: BL0937 Energy
    voltage_divider: ${voltage_divider}
    current_resistor: ${current_resistor}
    update_interval: 60s

What do I need to change to stop this?
Any ideas gratefully accepted.

Cheers,
DutchTuatara

2

what’s the point here?
what readings do you get for known resistive load while on/off?

3

This is after calibration, as initially the indicated current was only 40mA, when using a 2kW resistive load, fan heater.
After that, current read out is okay when using, but remove the load, current value should be 0A, but still shows ~8A.
That’s what is wrong.

Unplug the device altogether. After 2 hours, plus back in, still incorrect value shown.

Is there a way to reset to zero, before the next measurement cycle?

4

I’m not familiar with your device but doesn’t sound correct to me.
What are you getting on esphome logs?
Ps. fan heater is mainly resistive load but not purely.

5

Not home right now, at work.
Will check logs later.
Yeah, I’m aware not 100% resistive. The fan motor itself causes issues. I’m not after 100% accuracy, but the indication should be close
Initial voltage was something like 480V, although at outlet it is 230V.