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Difference of energy usage daily usage vs counters

Posted: Monday 21 October 2024 16:41
by infoed
Version: 2024.1 stable
Platform: docker on Sysnology NAS
Plugin/Hardware: NAS

I've noticed serious differences in energy meters between the usage and counters.
What I did:
- take the january and february monthly reports of my P1 energy meter device which connects to hardware device P1 Smart Meter with LAN interface
- copy / paste the reports to excel. Note: do not use the download to xls option since that option does not download the counters!
- make calculations of daily usage based on the daily counters. Example usage T1 of Date X = counter T1 (date x+1) - counter T1 (date x)
- compare this calculations with the daily usages.

I did this for T1,T2, R1 and R2. What I found:
- T1 has differences, T2, R1 and R2 does NOT!
- T1 difference in one month (jan 2024) almost 1,5 kWh
- did the same for september 2024. Again a difference of about 750 Watt
- Counters in domomicz are the same my energy provider is measuring (I have a dynamic contract and they report the monthly counters)

So my question is why only T1 has this difference? And why is there a difference ?

Re: Difference of energy usage daily usage vs counters

Posted: Monday 21 October 2024 16:52
by waltervl
Probably related issue already on Github: https://github.com/domoticz/domoticz/issues/6143

And 1.5 KWh on what total total size? Yes, there should be no difference, but 1.5kWh is 40 euro cents in my country so also not a big deal difference.
You are always welcome to look at the source code her https://github.com/domoticz/domoticz and find the source of your issue.

Re: Difference of energy usage daily usage vs counters

Posted: Monday 28 October 2024 13:16
by infoed
Thanks for pointing me to the related issue. Indeed, I've noticed the same timestamp issue (not being 00:00)

On a year base that rounds up (for me) up to tens of euros..
Therefor these values can not be used to check the suppliers invoices and I have to use the counters.
No problem, but a "need to know".