Cumulative Flag information


I’m hoping someone might be able to clarify the use of the Cumulative Flag when it’s set to 1 (c1=1). Currently I am making API calls with v1 (Energy Generation) and v2 (Power Generation) also voltage and temp. It appears as though that the PVOutput site is always 100Wh behind what the API is sending for v1, eg at 08:55 this morning v1=700 however the site is only showing 600Wh. This is pretty consistent over the entire day. Does the flag do anything else other than represent that v1 is reset to 0 at the start of the day? Perhaps some sort of calculation?

Happy to provide more data if needed.


That is all that is does.

  • 8:00 v1=10000
  • 8:05 v1=10100
  • 8:55 v1=10700

Would result in -

  • 8:00 v1=0
  • 8:05 v1=100
  • 8:55 v1=700

Hi. Thanks for the info and sorry for the delay in responding.

This isn’t what I’m seeing…

API call…
08:55 v1=700
09:00 v1=800
09:05 v1=1000

gives me on PVoutput
08:55 v1=600
09:00 v1=700
09:05 v1=900


Please provide the actual requests sent -


  • addstatus.jsp?t=8:00&v1=10000&c1=1
  • addstatus.jsp?t=8:55&v1=10700&c1=1

The above sent using a web browser results in v1=700 at 8:55AM

I’m using the solariot GitHub project. From the debug logs the API calls are as follows…



Looking at the resulting data on the 21st May -

  • 8:55AM, v1=0.600
  • 9:05AM, v1=0.900

900 - 600 = 300

There is a 300Wh difference which matches up to the difference between the 9:05AM and 8:55AM requests

  • 8:55AM, v1=700.0
  • 9:05AM, v1=1000.0

1000 - 700 = 300

But it still doesn’t explain why there is a 100Wh difference, also look at the total yield for the day…

v1 for the entire day (21/05) according to the inverter and the API is 12300.0…

but the site reports v1 as 12200.0

EDIT - I just tried sending an update today via a browser (to prove/rule out the GitHub project) and the same result occurred…the site reports 100Wh less than what was sent


You’ll have to check what the first v1 value sent was, the latest v1 value is subtracted from this value.

Testing on a fresh day produces the correct results.

So I have data from 7th June as follows…

08:40 0.0
08:45 0.0
08:50 100.0
08:55 100.0

09:10 100.0
09:15 200.0

17:15 5200.0
17:20 5200.0
17:25 5200.0
17:30 5200.0

and the corresponding site data for the same timestamps
08:40 0.0
08:45 0.0
08:50 0.0
08:55 0.0

09:10 0.0
09:15 100.0

17:15 5100.0
17:20 5100.0
17:25 5100.0
17:30 5100.0

The API data does not match what is being reported on the site. At 17:30 it is 5200 but the site says its 5100 and the discrepancy between the first 100Wh being sent via the API and the site recording it is 25 mins which I don’t understand.


This would be the problem, a cumulative c1=1 parameter only registers / resets after the first positive reading, which would be 100Wh at 8:50. The reading at 8:50AM will be reset to 0, from 100 and every other subsequent reading will be offset by 100.

If the script is always resetting to 0 each day then there is no need for the cumulative and it should not be sent and you will have the correct values. c1=1 is only intended to handle lifetime values that do not reset each day.

Thanks so much for that. I’m definitely going to remove the c1 flag in this case, I might even feed this back to the git project maintainer.

Thanks again for all of your help, you’ve been great.


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