background: i’m using two current monitors (2-chan 70amp and 4-chan 100amp) to collect data on two VFD well pumps. each pump is on a 40amp dual pole breaker. the VFDs alternate in operation every 12 hours but should otherwise draw the same amount of power. it is irrelevant i think, but the VFDs convert the 2 phase power to 3 phase.
i have one VFD on the 2-chan 70amp current monitor, the other is read on 2 channels of the 100amp monitor. i get the impression after reading around the forums that you maybe shouldn’t use a board that is pre-configured to a higher rating, but i’m already using it now and am very resistant to buying different/more hardware.
the problem: i’m using the pecmac125a python code for both sensors but i’m getting readings with the 70amp board that are well above reality by a factor of 8 or 10. Currently it reads at 65 amps per channel which would trip or blow up the breaker were it accurate. if i divide the current by 8 or so (%current/8) i get a more sensible reading that is closer to what i read with a clamp-style multimeter directly on the hot wires from the breaker, but i feel like this is not a good or accurate workaround.
Also, I have the 4-chan 100amp current monitor reading the other VFD and this appears to be giving near-accurate readings, but now I doubt the veracity of that data as well.
Here are some pics of 70amp hardware and readings:
This graph is from the 2 channels of the 100amp sensor and seems to return accurate data, at least it doesn’t exceed the max rating on the breaker. The two graphs SHOULD be nearly identical except one is off while the other is on (ignore the spike, the ras-pi choked up):
