Issue with recorder.import_statistics for Historical Energy Data

[cloudbr34k84]

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Background

I am trying to import historical solar energy production data into Home Assistant using recorder.import_statistics. My energy sensor (sensor.symo_10_0_3_m_1_total_energy) already tracks a cumulative total energy value in Wh. I am trying to ensure that Home Assistant correctly processes this historical data without calculating incorrect deltas.

What I Know About state and sum

• state should be the exact total energy reading at a given timestamp.
• sum should be the total accumulated energy recorded by Home Assistant (it should not be a daily increment but should always be increasing).
• sum does not represent the sum of all previous state values, but rather the cumulative energy tracked by Home Assistant.

Data I Am Trying to Import

Timestamp	State (Total Energy in Wh)	Sum (Total Accumulated Energy in Wh)
2020-08-28 00:00	15545.3147	15545.3147
2020-08-29 00:00	41992.8947	41992.8947

Approaches I Have Tried

1. Importing with sum matching state

action: recorder.import_statistics
data:
  has_mean: false
  has_sum: true
  source: recorder
  statistic_id: sensor.symo_10_0_3_m_1_total_energy
  unit_of_measurement: Wh
  stats:
  - start: "2020-08-28 00:00:00+10:00"
    state: 15545.3147
    sum: 15545.3147
  - start: "2020-08-29 00:00:00+10:00"
    state: 41992.8947
    sum: 41992.8947

Result:

• Home Assistant calculated an incorrect delta.
• Instead of sum reflecting the total accumulated energy, it treated sum as a daily increment and subtracted previous values, leading to incorrect results (e.g., sum showing 10902.27 instead of 41992.89).

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2. Importing with sum as a cumulative difference

stats:
  - start: "2020-08-28 00:00:00+10:00"
    state: 15545.3147
    sum: 15545.3147
  - start: "2020-08-29 00:00:00+10:00"
    state: 41992.8947
    sum: 26447.58  # difference between two state values

Result:

• Home Assistant subtracted the previous state value again, leading to an incorrect sum value.
• The sum field is not behaving as expected when importing historical data.

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The Issue

• Home Assistant appears to be treating sum as a daily increase instead of an actual running total.
• The imported sum values are not matching the expected total energy values.
• The statistics are misrepresenting energy trends because of how sum is handled.

What I Need Help With

1. How should sum be defined when importing historical data for a sensor that already tracks a cumulative total?
2. Should sum be left out, or should it match state?
3. Is there a way to manually adjust Home Assistant's internal statistics processing to prevent incorrect delta calculations?
4. Are there any required steps (e.g., purging statistics) that I should follow before re-importing?

Would appreciate any guidance on how to correctly import historical energy data for a sensor that already tracks a cumulative total. Thanks in advance! 🙏

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