Actual usage per day?

[EddyG]

Please explain.

I've got 3 electric usage sensors (power groups) which give only the minimal and maximal values.

[waltervl]

I think you use the incorrect devices (or the plugin author selected the wrong device).
You probably have the type Usage Electricity device:
https://www.domoticz.com/wiki/Dummy_for ... lectricity

That device indeed shows only current Usage and has no good reporting features. If you created them yourself change the device type and change the scripts. Else contact the plugin/integration author to ask him to change the device type