question

karlschindler avatar image
karlschindler asked

disable discharging when car is charging

Hello,


i'm new to Victron but long term smarthome user/DIY developer and know something about modbus. But i didn'nt understand some relationships of setting in my ESS System.

I have 3 Multiplus2, Pylontech Battery and CerboGX running large image.

ESS mode is 1, Optimized mode or 'keep batteries charged' and phase compensation enabled

ESS State = 5, Optimized Mode /w BatteryLife: SoC below dynamic SoC limit

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I want to disable discharge battery when my e-car is charged by an go-e Charger.

My idea was to set the related state through MQTT and the Victron Nodes.

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But i was not able to figure out which are the right/best settings i have to change.

Is it ok to set just the ESS state to 9 - 'Keep batteries charged' mode is enabled?

cerbo gxPylontechNode-REDModbus TCP
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3 Answers
wkirby avatar image
wkirby answered ·

How about using the "Charger Only" function when you want discharge disabled?
Use the VE.Bus System Control node and use the "Switch Position". Set On for normal operation and set to "Charger Only" when you want to stop discharging.
Caveat is that if the network fails during "Charger Only" then AC-Out will not have output.


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enodev avatar image
enodev answered ·

I am trying to achieve the same. Assuming the house battery is smaller then car battery, whenever the car charging is active, I want to use as much PV as available but limit discharge of house batteries.


I think I have successfully achieved that by limiting “Max Inverter Power“ ESS setting to the available MPPT power. That way all PV power goes via inverter to AC loads and never to house battery, and also house battery will never get discharged because PV provides enough power for inverter.

When car charging is not active, max inverter power can be set to -1 to disable limiting and allow house battery discharge again…



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karlschindler avatar image karlschindler commented ·
great idea, like that, thanks


only need to get this information from my Fronius Inverter because the Vivtron MPPT ist not connected yet, and then i have to add both sources together, but thats possible.
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enodev avatar image enodev karlschindler commented ·
With Fronius it is a bit different, because it is connected to AC out, so I think the best way would be to disable inverter completely when you detect that car is charging. Correct?
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tyr avatar image
tyr answered ·

I use NodeRed to query the state of my wallbox (OpenWB) via Mqtt.

If the car is connected (MQTT signaled) and charging mode of OpenWB is "Sofortladen" (MQTT signaled) and chargingpower of the wallbox ist above 500W (arbitrary value below minimum chargepower, MQTT signaled) I shift the gridsetpoint positive to the ampount of chargingpower. This way Incan use my batteries to back everything else in critical loads and only compensate for the wallbox from grid.

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