I hope someone can help me with pointers to resources that explain how to achieve…
I have an emonPi running well for quite a while and also one of Robin Emley’s mk2pvrouters for diverting surplus solar.
I’ve recently installed a battery which is working fine, but there can sometimes be a bit of conflict between the battery and the Router in respect of priority for energy because both systems use CTs at the same grid import position and both attempt to keep current at that location close to zero.
What can happen is that - possibly because of small calibration errors - the battery overshoots and exports a bit of stored energy towards the grid which the Router then rightly intercepts and absorbs into diversion loads. Occasionally this develops into a feedback loop until my diversion loads are pulling power from the battery at their full load - which is not desirable.
It occurs to me that it may be possible to program a spare output pin on the emonPi so that it changed state when the battery’s own input/output CT went negative - ie when the battery was discharging. (this is not the battery’s own grid sensing CT, but is my monitoring CT sent to emonPi from emonTX).
This pin could potentially be patched into the Router. I’m hoping I could modify the router script and use this signal to make diversion conditional on the battery not currently discharging.
Sadly, I don’t know whether this is possible or where to begin researching. If someone else here has done something similar, I’d appreciate some tips.
Many thanks, David.