I’m hoping to install an Iotawatt at a friends off-grid cabin. He generates power from the creek. I’m not exactly sure on the details, but I think the pump is spinning an inductive motor which generates 3-phase 600 ish volts. That goes from the power house up to the cabin, to a transformer that creates standard 240 split phase. It should be a pretty standard install, one voltage reference on one of the legs, one CT clamp on each phase, plus one clamp on the dump loads.
The interesting bit is the variable voltage due to fluctuations of the water flow. There is a load controller that is basically a PID that turns on and off baseboard heaters in an attempt to keep the voltage steady at 120. If a breaker goes or some heavy loads are turned on suddenly there can be quite a fluctuation in the voltage while load controller is compensating. Extreme situation could be between 80 VAC and 160 VAC (so peak voltage could be upwards of 200?)
If I’m understanding the design correctly, the upper limit on the voltage input is clamped at 3.3v to avoid damaging the MCU, so at some point, the calculated voltage will top out. So even if the cabin is at 160 VAC, the Iotawatt might be reading it as 140.
What is the calculated max input with the 12K/1K divider?
If I needed to increase the range, is it as simple as replacing R32 with a higher value resistor and calibrating the VT?