my garage is connected to AC-IN and the house to AC-OUT of the MP. I would like to switch the self-consumption from battery to critical loads only as long as the EV is charging.
I tried to find if there is either a modbus address or mqtt topic available, which allows external control of the ‘self-consumption from battery’ configuration: 4. Configuration
Could someone help me out? If this is currently not controllable, I might need to set the inverter power to 0 and accept the grid consumption in the meanwhile.
The concept that does the trick is different, when you are running an ESS, regardless where the loads are connected.
Simply exempt the Load that goes into the EV from battery-backup by adding that amount to your actual grid-setpoint. This way the battery will only compensate for the other loads.
This is the way I do it…works like a charm, using Node-Red, as I have a non victron wallbox with two charge points.
However, this will not work while DESS is active, only with local ESS.
Did not even know that the grid limit is only respected in certain limits, when using DESS (I have the thread now).
Looks like I also have to role my own control layer, which takes the various aspects into account, which are specific for my situation
I have an Alfen Eve, which will be controlled by evcc. So I only have to control the power flow and assignments overall, which still is interesting enough.
…evcc does have a good, open APi including one based on mqtt.
The basics are to collect the actual power / consumption that is flowing into the EV via the charger and add that amount to the grid-setpoint of the ESS on the GX.
Should be fairly easy with a single Node Red flow.
The “trick” is to determine the charge mode that applies to this rrule. obviously, while charging PV only, the battery is of no concern.
Also evcc does already have this: Home Battery | evcc - Sonne tanken ☀️🚘 … so maybee evcc alone can do the trick with its own integration to victron gear.
No, when you tell evcc to avoid discharging the battery while charging the car, it simply disables battery discharging completely (by setting the minimum SOC in ESS to the current SOC).
Ah, OK…so this way, other loads will not stay supported by the battery during that time.
Interesting way, evcc thinks this is a feasible use case…but it is a charging solution, not an EMS after all.
I think it’s the best that can be done with the current architecture, evcc’s control loop runs every 30 seconds times the number of loadpoints (by default), plus they support a number of batteries with different control strategies/interfaces.
If one assumes the rest of the loads will be small compared to the EV charger, it doesn’t make much difference anyways, just don’t turn on your washing machine while the car is charging from the grid…