Hello. My iotawatt arrived today. Tomorrow I hunt for a locally useful 9-12VAC VT and a 5VDC 1.2A power supply, and then pay my pet sparky to play behind the distribution board, because NZ law specifically states I can’t do that. (Sensible, really)
To my situation: When I draw current from the grid, my revenue meter spins forwards and I get charged $0.30/kWh. When my solar panels exceed my local demand, my revenue meter does not spin backwards. Rather it tracks the reverse current separately and I am paid $0.08/kWh (I.e. my FIT is appalling).
Looking over the iotawatt code on github, it seems to me that when negative values are enabled, the sample averaging code for each CT will count the positive events up (“spin the meter forwards”), but count the negative events down (“spin the meter backwards”). Which means the iotawatt will not track my feed-in correctly and be at variance with the revenue meter.
have I understood the code correctly? Or is it possible to set the code to accumulate positive values in one variable and accumulate negative values in another?
if my understanding is right, my next question is, how ‘tight’ is the sample acquiring loop? If I add a new variable and a new config value and on every iteration of each of the 14 sensors, use an if statement to add the accumulated value the ‘right’ variable, will that one ‘if’ be the straw that breaks the camel in half and drop the sampling rate to nothing exciting?
I can, and probably will, start playing in a few days, but I figured it would be more efficient to ask first. (I can’t be the first PV house without nett metering!)
Thanks in advance.