Recently I deployed Iotawatt and want to feed pvoutput from it. Currently I use python script to read some cloud api from another metering system to do the same.
Once I deployed it, I made test account in pvoutput and started comparing result.
Trouble is that I have night “production” of 3W reported on my inverter cable. After some diagnostic run, I found:
- it is current in this cable as turning fuse off stops this reading
- It is correct direction as it is the same as real production. I made it bidirectional and during minimum light it shows reverse direction of 5-20W but when inverter goes to sleep it remains solid 3W in production direction
- It is certainly false positive as there is no energy in inverter at night.
I tried to alleviate issue by adding “(inverter -3) max 0”. This does prevent false power reading in pvoutput but energy reported by iotawatt still increases by 12Wh every 4h.
The only way I can explain this false reading is apparent power draw by some capacitance in inverter. As it would be turned 90 degrees, I can imagine further phase shift either in reference transformer or CT to be on the other side of 90 degrees making it wrong direction. However, this still does not make sense.
Any tips how to either fix, compensate or overcome this false reading?