Hello all and thanks for taking the time to read my post. Apologies, if I’m asking questions covered elsewhere – but I think my setup is at least a little different to the norm to warrant a new post. Feel free to hurl abuse at me if not.
We have just had a domestic PV system installed and this has fuelled an immediate obsession with power usage.
As you’ll know there are various third party tools available but I wanted a DIY solution which a) I understood instead of just a mysterious box, and b) I had control over, particularly the generated data. When I arrived at this site today after many hours of fruitless searching I concluded I had likely found what I needed.
However, that last thing I want to do is rush into buying the wrong (or least appropriate) kit.
Thus, I guess I need your help in answering a couple of fundamental questions.
Can I achieve what I need with the hardware/software detailed here?
If so, which hardware solution is most appropriate?
OK, in no particular order some basics about the setup we have here and what I’m hoping to achieve.
A. I mention we have just installed PV. (A battery will be added in the future but for now it’s just panels and inverter.) Whilst a sophisticated solution which incorporated the solar into the whole view might be a ‘nice-if’ it isn’t essential. The three phase inverter (Solar Edge) has logging and associated portal built in. So that data will be covered.
B. My primary interest is in what energy is still being pulled from the grid and when. Even though this is just a domestic property we have a three phase supply. The three phase inverter splits a third of the generated PV power to each phase. So I want to monitor the draw from the grid on each phase so I can review which takes the most load and over what period.
C. Absolute precision is not essential, e.g. I wouldn’t need to try and estimate cost to the nearest penny. Instead, I just need broad accuracy to display usage of each phase.
D. I assume I need three CT sensors one for each phase cable? (I can see there is a fourth separate neutral cable but I assume I don’t need to monitor this?)
E. As I understand it (and excuse my ignorance here) but the CT sensors can’t understand flow direction? Thus, if the cable is periodically drawing current from the grid, then getting current pushed back by the PV the sensor can’t apply positive/negative of flow so just gives the quantity regardless of direction.
If this is the case do I need to “exit sub” at this point since it’s not possible to capture the data I need?
Any help and insights at this stage would be very welcome.