Hi. Proud owner of an excellent new EmonEVSE
First, here’s my rough setup:
I’m 80% complete writing a python script on a raspberry pi to manage PV from three sources between my Victron/Pylontech house battery, Ecodan heatpump/DHW cylinder and EmonEVSE/eGolf on the front drive.
The EmonEVSE is connected directly to the meter, so isn’t visible to the Victron grid meter, which is setup to optimise self-consumption (plus winter overnight charging).
From my python script, I want to be able to divert PV to the car under two scenarios:
- Simple: when the house battery is full, to divert away from grid export
- Harder: before the house battery is full, alter the “grid set point” (using PyModbus) of the Victron to 5amps/1.2KW and trigger charging on the EmonEVSE.
Under the Simple scenario, the power has no opportunity cost to me, and otherwise goes to the grid. So I don’t really care about stopping when the car hits a threshold SoC, or if its driven off etc.
However, under the Harder scenario, the power could otherwise be charging the house battery, so I want to be able to monitor the car state of charge.
In addition, while I appreciate the issue with wearing out contractors, I want to be able to stop charging programmatically once it has started. In reality, given the “buffer” of the Victron it’s unlikely to happen more than once/twice a day.
I’ve understood the following challenges/limitations from the EmonEVSE documentation:
- It seems that it isn’t possible to get the eGolf state of charge directly from EmonEVSE over the http API (please correct me if wrong), but as I can get it using Python Weconnect VW, that’s not the end of the world.
- I can trigger a manual override using this API call (Set the manual override | OpenEVSE WiFi v4), for example to start charging at 5amps. However, while I could stop this charge by clearing the manual override (Clear the manual override | OpenEVSE WiFi v4), I wasn’t able to modify the current mid-charge by sending another post request because while I got a successful response, it didn’t seem to action the request. Is this a bug, or intended?
Do folks around here have any suggestions about:
- Overcoming the issues with the manual override above?
- Whether I should use “PV divert mode” instead, and perhaps use the manual override that disables/stops charging?
- An easy to install (i.e. battery powered and wireless) grid meter I could use to move my Victron meter location from the distribution board out to the electricity meter.