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P1 Energy Weekly Graphs : Error in calculation

Posted: Wednesday 10 May 2017 22:06
by Gaston
Hi,
Attached I've added a snip of a graph where you can see the daily use and delivery of power in Watt.
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In summary:
My opinion: The daily graph looks accurate, the weekly (with daily summary) is not.

If you look at the top right, for May 10th, I've delivered absolutely more than used from the grid.
Looking at the blue line, from 0:00, let's say 200W, for 8 hours is 1,6kWh used from the grid.

Now look at the 2nd bar graph which shows the daily sumary.
At the right side of this daily graph for "Woe" (which is the day above in the line graph)
According to the graph I would've used 5,15kWh from the grid (blue), and delivered back: 3,4 kWh (green).
For the blue graph the bottom light part displays 1,7 kWh, which could be the 1,6 kWh I estimated (8 hours x 200W)

The dark blue part is not correct, not sure where this is coming from.
The green part showing 3,4kWh delivered to the grid is definitely not ok. I would guess this is about 6 hours x 3kW = 18kWh
The panels generated today 34 kWh, minus the use of appliances, give or take, 18kWh could be okay, definitely not the 3,4kWh

The next few days I'll be monitoring the P1 meter data on the display by hand.

Does anyone else have a similar issue about the weekly bar graphs, not showing the correct daily summary?
btw, am I still correct a left-shift on a graph entry (for gas in my case) doesn't delete the entry, even though I need to confirm this with the popup?

Using the following setup:
Version: 3.7449
Build Hash: 9df6061
Compile Date: 2017-05-08 18:36:04
I'm using an ESP8266 reading the P1 meter and sending each 10 seconds the data to Domoticz.

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Re: P1 Energy Weekly Graphs : Error in calculation

Posted: Thursday 11 May 2017 0:51
by Gaston
Hereby the results of the first 40 minutes of today May 11th.
For some reason Domoticz shows a use of 3,4kWh and 1,4 delivery to the grid in the middle of the night.
I just checked the roof for fairy dust, but I found nothing on my solar panels.

The dark blue area of 3,4kWh is the same from yesterday, and as you can see in the table, also for some (but not all) other days

I first thought Domoticz is receiving some crazy content without crc check?
But then again, the top bar shows correct values. Only the daily summary is strange.

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And to complete the data entries for the top graph:

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Re: P1 Energy Weekly Graphs : Error in calculation

Posted: Thursday 11 May 2017 8:54
by Gaston
I can understand that. To get it clear what it shows exactly, I would need to check the code.
The top bar could show the value at current notice of measurement, you could miss a peak or dip somewhere.
I would like it more to show the kWh difference in those 5 minutes. But that's not what I'm after.

I'm having a messed up average for the 2nd graph. Where does that 3,4kWh and 1,4kWh come from at midnight?

Re: P1 Energy Weekly Graphs : Error in calculation

Posted: Thursday 11 May 2017 12:07
by Gaston
I think it has to do with the values Domoticz receives from the P1 meter. Something is not right.
You can see in my previous graphs "energieverbruik" and "energie retour" where grayed out, so not displayed (not sure why).

I have very odd values in the table:
-3421725 for consumption
1421243 for delivery

I was planning already to experiment with ESPEASY as it has a different approach.
Currently the implementation of the ESP8266 does the CRC and sends data to a domoticz P1 device.
If I understood correctly with ESPEASY: Domoticz connects to the ESP, fetches the data and does a CRC

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