INA226 Max measured current its 0.818A

[zac99]

The problem

The configuration has a current consumption above 1.5A and the INA226 shows a measurement of 0.818A. I set up two modals and they have the same reading.

Which version of ESPHome has the issue?

2022.1.2

What type of installation are you using?

Home Assistant Add-on

Which version of Home Assistant has the issue?

2021.12.1

What platform are you using?

ESP32

Board

ESP-32WROOM-32

Component causing the issue

INA226

Example YAML snippet

i2c:
  sda: 21
  scl: 22
  scan: true
  id: bus_a    

sensor:
  - platform: ina226
    address: 0x45
    shunt_resistance: 0.1 ohm
    current:
      name: "INA226 Current"
    power:
      name: "INA226 Power"
    bus_voltage:
      name: "INA226 Bus Voltage"
    shunt_voltage:
      name: "INA226 Shunt Voltage"
    max_current: 5.0A
    update_interval: 2s

  - platform: ina226
    address: 0x40
    shunt_resistance: 0.1 ohm
    current:
      name: "INA226_2 Current"
    power:
      name: "INA226_2 Power"
    bus_voltage:
      name: "INA226_2 Bus Voltage"
    shunt_voltage:
      name: "INA226_2 Shunt Voltage"
    max_current: 5.0A
    update_interval: 2s

Anything in the logs that might be useful for us?

No response

Additional information

No response

[mjess]

I'm not an expert for this device but it looks like expected behavior, as the INA226 can only measure up to ~819mA.

Unfortunately I found only a german explanation but basically it says that the INA226 has a resolution of 2.5 µV per bit. The register is 16bit wide but one bit is for the sign, which leaves 15bit for the value: (2^15 -1)* 2.5µV = 81.9175 mV (max value) The typical INA226 has 0.1Ohm shunt resistor. 81.9175mV / 0.1 Ohm = 819.175mA max current range. Explanation (in German): https://wolles-elektronikkiste.de/ina226

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[ryny24]

I had the same issue. Could not get above 0.82 A, until I removed the R100 resistor and used an external shunt. Just FYI for anyone who finds this thread...