C1=1 - first positive value is subtracted from all subsequent values

Problems
#1

Hi,

I am uploading solar data to PVOutput every 5 minutes using the addstatus API with c1=1. My inverters (Victron MPPT) reset the daily yield to 0 at midnight. Uploads start at 05:30.

Observed behavior today (01/06/2026):

From 05:30 onwards, the inverters report v1=0 – PVOutput correctly shows 0.000 kWh for all these uploads.

At 05:50, the first positive value is sent:

d=20260601&t=05:50&v1=10&v2=4&c1=1

PVOutput shows: 0.000 kWh instead of 0.010 kWh

From that point on, every value is exactly 10 Wh lower than what is sent:

|Time|Sent (Wh)|PVOutput shows|
| --- | --- | --- |
|05:50|10|0.000 kWh|
|06:40|20|0.010 kWh|
|07:05|30|0.020 kWh|
|08:05|70|0.060 kWh|

Key facts:

  • Uploads correctly started at v1=0 from 05:30 onwards
  • The inverter counts in 10 Wh steps (minimum resolution)
  • The first positive value (10 Wh) is consistently subtracted from all subsequent values
  • This results in the daily total being 10 Wh too low at end of day

My question: Is this expected behavior with c1=1? If the daily counter starts correctly at 0, why does PVOutput subtract the first positive value from all subsequent values?

Is there a recommended way to upload a daily cumulative energy value with 10 Wh resolution so that PVOutput displays it accurately?

Thanks in advance!