Importing energy from sensor to meter

[janorn]

When importing sensor data with accumulated energy usage all goes fine except the meter restarts from zero. History is there but new data starts from zero. I even tried overwriting all previous data. Any idea what is wrong?

[mayerwin]

Thanks for reporting this, and sorry it took a version to get to the bottom of. It was a real bug on our side, and the fix is in 1.3.1.

What was happening

Home Assistant does not store a meter's running total as an absolute reading. It continues it: on every statistics compile it takes the sensor's own most recent 5-minute statistics row, reads the running total from it, and adds only the increments since. When the sensor has no such row, it starts again from zero.

The import computed its splice offset purely from the destination's hourly statistics. If you had just created the destination meter, it had no hourly row yet, so no splice point was found and the source's history was written at its own absolute values. Your destination then began compiling its own statistics from zero, right after the history that ends at the old meter's total. The history was genuinely there, exactly as you saw, but the two halves sat on different baselines, which is what the Energy dashboard shows as a drop back to zero.

What changed

The destination's 5-minute rows are now used as the splice point when it has no hourly row yet, so the two series are joined properly. And a destination with no statistics of its own at all now gets its running total seeded at the end of the imported history, so the readings Home Assistant compiles from then on carry on from there instead of restarting.

For a meter that already restarted, including yours

Preventing it does not help anyone it already happened to, so the import now also detects it. Re-run the same import, or just click Preview first: if the destination's stored series restarts from zero partway through, the result explains what happened, when, and offers a Repair running total button.

Repairing lifts every statistics row from the restart point onwards so the two halves line up and your future readings continue from the corrected total. Rows before that point are left alone, and your per-hour and per-day figures do not change, only the running total moves. You do not need to re-import anything, and it works even if the old sensor is long gone.

It is never automatic, it re-checks your database when you click rather than trusting what the panel showed, and clicking twice cannot double the correction. It also declines to offer anything unless the series shows a single unambiguous restart, so a sensor whose total legitimately goes down is not touched.

Back up your database first, as always with this integration. Please reopen or comment if the repair does not put your meter right.

[janorn]

It's the most recent update .2 release.

[mayerwin]

Thanks, that screenshot tells me a lot.

First, the important distinction: the History panel draws a sensor's state. The Energy dashboard does not use states, it uses statistics, and the two are stored separately. So before anything else, one question: does the Energy dashboard also restart from zero for this meter, or is it only this graph? That answer decides whether there is still something to fix on my side.

Here is what your graph is showing. The Utility Meter reads about 13 400 kWh up to roughly 19:00 on 25 September, which is the history imported from the Shelly sensor, and from that point on it reads its own value, which started at 0 and is now 64.05 kWh.

That part is not something the import can fix, and I should have said so earlier. A Utility Meter counts from the moment you created it. The Shelly sensor counts from the day the device left the factory. Those are two different quantities, and the meter keeps its running value inside the helper itself rather than in the database, so writing history into the database cannot move it. No matter what gets imported, the meter's own state continues from where the helper is.

Home Assistant does give you a way to move it. Go to Developer tools > Actions > Utility Meter: Calibrate, target the meter, and give it the value you want it to read. Set it to the Shelly sensor's current reading and the meter carries on from there instead of from 64 kWh.

One warning about the order, because it matters. Calibrating raises the meter's state in a single step, and Home Assistant records that step as consumption in the statistics. If you calibrate after importing, that jump lands on top of the history the import already wrote and your energy total gets counted twice. So calibrate first, then run the import. The import will then find the two sensors already at the same level and simply fill in the history behind it.

To answer your other question: no, not the debug JSON files, and please do not attach the 150 000 line ones. What I asked for is much smaller. Run Preview on the pair in the integration's own panel and screenshot the result box it prints, the part that mentions the running total.

And one more thing I need to know: did you tick Overwrite or Fill gaps for this import? Those take a different path through the running total code, and I want to be sure which one you are on before I go looking further.

[janorn]

I have done both. This is a preview from fill the gaps.

[janorn]

So a question. I created this meter because I plan to replace the Shelly sensor to a new sensor. Reading the thread where I found your tool. As i already have several years of stats with the old sensor I wanted to future proof the energy statistics with a meter where I can easily switch sensor if it breaks or if I need to replace it due to some other reason.
So as this is a new setup I can trash this meter and redo it. What is your recommended method to get this right.

As it is now both the historical and current view shows same value starting from when I ran the overwrite last time.

[mayerwin]

Thanks, that is exactly what I needed, and your plan makes sense: a meter that stays in the Energy dashboard while the sensor behind it can be swapped.

First, a correction to my last reply: do not calibrate the meter. I told you to calibrate first and import after. That was wrong. A meter starts compiling statistics within minutes of being created, and from then on any calibration is booked as consumption, whichever order you import in. Your history would be counted twice.

Your Preview also shows why a clean restart is worth it. It reports nothing left to import, yet the meter's history sits about 13 409 kWh above the Shelly's own statistics, so after the earlier attempts the meter most likely counts that history twice. (The offset line itself should not have appeared at all with nothing to import; that is a display bug I have fixed for the next release.)

Recommended way to do it

1. Update the integration to 1.3.3. It fixes a case where re-running with Fill gaps or Overwrite left the lifetime total too low.

2. Delete the current meter helper.

3. Create a new Utility Meter with a different name from the old one, so it gets a fresh entity ID and nothing left over from the old one can interfere. Input sensor: the Shelly. No reset cycle. Do not calibrate it.

4. In this integration's panel: source is the Shelly, destination is the new meter. Leave Overwrite and Fill gaps off, there is nothing in the new meter to overwrite. Click Preview first. You should see one of these two lines, and either is right:

   • "running total would be seeded at ...", if the meter has no statistics of its own yet, or
   • "running total would be realigned by ...", if it has already compiled a few minutes of its own.

   The amount is the total the Shelly has recorded since Home Assistant started keeping its statistics, which can be lower than the reading on the device itself if the device was counting before that.

   If you instead see "Cumulative-sum offset would be applied", stop and send me that screenshot. Otherwise click Import.

5. Optional tidy-up: Developer tools > Statistics will list the old meter's statistics as no longer provided, with an option to delete them.

What you will see afterwards

The Energy dashboard shows your years of Shelly history running straight into the meter, with the correct lifetime total.

The History graph of the meter will still show a drop where the imported history ends and the meter's own readings begin. That is the meter's state, which the helper keeps for itself and no import can change. It is harmless: the Energy dashboard does not use it. Just leave it, and do not calibrate to hide it, for the reason above.

When you replace the Shelly later

Open the meter's options, the dialog in your screenshot, and pick the new sensor as the input sensor. No import is needed, the meter carries on counting. How a Utility Meter handles the first reading from a sensor that starts at a different value is Home Assistant's own behaviour rather than this integration's, so check the meter the day after the swap.

For completeness, the other route is to skip the meter: keep the Shelly in the Energy dashboard and, when you replace it, import its history into the new sensor with this integration. Your meter route has the advantage that the Energy dashboard never needs to be reconfigured.

[janorn]

I uploaded the file that is smallest as the other will not upload.

[janorn]

merge_history__sensor.shellyem3_3494547b5f9f_channel_a_energy__to__sensor.tvattstuga_shellyem3_3494547b5f9f_phase_a_varmepump_l1_energi__stats__2026-09-26T13-13-38.json

[janorn]

Regarding no 3. No cycle was set. Don’t know where I can verify this after creation.

[janorn]