"The unit of measurement of some entities has changed" warning messages

[lechercheur123]

Hello

Describe the bug
Everytime I restart Home Assistant, I have 2 messages saying the unit of measurement of 2 entities have changed:

(Sorry it is in French. It is saying "The unit of sensor.charger2_power_reactive_import has changed" and "The unit of sensor.charger2_energy_reactive_export_register has changed"

If I click on one message, I get this:

In English it means:

The unit has changed
The unit of "charger2 Power Reactive Import" (sensor.charger2_power_reactive_import) has been changed to "kW" which cannot be converted to the previously stored unit, "var".
If the historical statistics values ​​have the wrong unit, you can update the units of the old values. The values ​​will not be updated.
Alternatively, you can choose to delete all historical statistics values ​​and start over.
How do you want to fix this issue:
Option 1: Update the unit of historical statistics values from "var" to "kW", without conversion
Option 2: Delete old data

The same warning can be found in the logs:

2024-11-24 16:05:10.127 WARNING (Recorder) [homeassistant.components.sensor.recorder] The unit of sensor.charger2_energy_reactive_import_register is changing, got multiple {'kWh', 'varh'}, generation of long term statistics will be suppressed unless the unit is stable and matches the unit of already compiled statistics (varh). Go to https://my.home-assistant.io/redirect/developer_statistics to fix this
2024-11-24 16:05:10.207 WARNING (Recorder) [homeassistant.components.sensor.recorder] The unit of sensor.charger2_energy_reactive_export_register (kWh) cannot be converted to the unit of previously compiled statistics (varh). Generation of long term statistics will be suppressed unless the unit changes back to varh or a compatible unit. Go to https://my.home-assistant.io/redirect/developer_statistics to fix this
2024-11-24 16:05:10.207 WARNING (Recorder) [homeassistant.components.sensor.recorder] The unit of sensor.charger2_power_reactive_import (kW) cannot be converted to the unit of previously compiled statistics (var). Generation of long term statistics will be suppressed unless the unit changes back to var or a compatible unit. Go to https://my.home-assistant.io/redirect/developer_statistics to fix this

It is not a blocking issue, but it is annoying to have to open these messages everytime I have to reboot HA (after an update, after a configuration change...)

To Reproduce
Steps to reproduce the behavior:

1. Restart HA

Expected behavior
Nothing

Screenshots
See above

Desktop:

• OS: Windows (HA is on a VM on a Proxmox hypervisor)
• Browser Firefox
• Version 132

Additional context
I think this issue might be linked to the charger. In fact, I have two chargers connected to my HA:

• charger, an Schneider EVlink Smart Wallbox 22kW, which is working fine with the OCPP integration. Its ID is "charger22kW"
• charger2, a eProWallbox Move from free2move, which I think is a crappy wallbox. Its ID is 1694AB070000244

I only have the issue with "charger2" (as seen on the screenshots)

To have 2 chargers on the same HA I used two instances of the OCPP integration listening to different ports, like this:

I guess this is the good way to do, no?

I will put the log file in attachment.
home-assistant_ocpp_2024-11-24T16-52-05.376Z.log

[onlyfornetwork]

I have the same problem,

it also occurs when the column is turned on by the integration

Wallbox Legrand Green Up 059006

[N3rdix]

The repair should disappear if you delete the old long-term statistics (if you don't need them from those entities).
I assume there was a reason to change the UOM of those entities, so this might be the only persistent option...

[lechercheur123]

If I delete the warning saying that the unit has been changed from 'var' to 'kW', at the next reboot I have a warning saying the unit has been changed from 'kW' to 'var'...
So this isn't a long term fix

[drc38]

You can try updating the logic here:

ocpp/custom_components/ocpp/sensor.py

Line 152 in a55913c

def device_class(self):

with SensorDeviceClass.REACTIVE_ENERGY

[N3rdix]

I created a PR to fix at least the power reactive sensors, maybe you can review if it'S fine from your perspective @drc38.
There is no equivalent for reactive energy in the device classes of HA as it seems...

[drc38]

I created a PR to fix at least the power reactive sensors, maybe you can review if it'S fine from your perspective @drc38. There is no equivalent for reactive energy in the device classes of HA as it seems...

Yeah, looks like I was looking at a fork that did not get merged by the devs. See my suggestion on energy in your PR. It's odd they added reactive power without adding reactive energy....

It should stop the warning by not giving it a device class.