Import historical energy data

[Lukasries]

It would be great if the integration could import historical energy totals (PV production, battery charge/discharge, grid import/export) from the E3DC system.
Right now, the Home Assistant Energy Dashboard starts from zero when the integration is installed, which means past data is lost.
Being able to sync or set initial totals from E3DC would make long-term statistics much more accurate and complete.
Thanks for considering this feature!

[jensihnow]

I like the idea, but while thinking about it I've concluded the following:

It would be great if the integration could import historical energy totals

I would consider this as not possible, due to the fact that Home Assistant (as far as I can recall) isn't supporting retroactive import of values for statistics and so on.

Right now, the Home Assistant Energy Dashboard starts from zero when the integration is installed, which means past data is lost.

But only if the integration is installed for the first time, as soon as it is installed and properly configured all current and historic values and statistics should remain as long as the integration is providing the sensors. Past data is not lost, it just never was published to the Home Assistant statistics.

Being able to sync or set initial totals from E3DC would make long-term statistics much more accurate and complete.

Even if this would be possible, you would have one big spike within your metrics / statistics. Depending on the time of install e.g., in December the spike would be so big any further would be un-readable. This is due to the fact that there is no history within the data to be persisted in statistics of Home Assistant. Therefore the one metric of "history data" would be one entry with a very large numbers.