Some of you have a EV-charger attached to their Victron solutions.
In most cases I charge my EV with PV surplus only. But in some cases it is required to charge my car quickly, when no PV or to few PV-power is available.
However in those cases I do not want to burden the house battery with the provisioning of an enormous amount of power (up to 11kW). Therefore I have created a Node-Red-based solution for a Victron platform supporting the wallbox “OpenWB” that takes following aspects into account (in case your Wallbox offers an open interface, you could also easily adapt the solution to your environment):
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As soon as a “Immediate/Sofort” or “Target/Ziel” charge is started, the module reduces the inverter power of the Victron inverter to a fixed level of “Grid/Netzladen W”, which usually corresponds to average household consumption. This means that the battery is not discharged any more than it is required for the actual house supply. The remaining energy is drawn from the grid.
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Once the EV charging process is completed, the inverter power is reset to the device maximum (“Std. Limit (W)” - in my case 13.6kW).
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If a DC-attached MPPT is connected and PV power is generated during the day, the inverter power is adjusted to the MPPT power level every 2 seconds. Regulation takes place in 100 watt steps and slightly below the actual MPPT power.
This ensures that the MPPT power is used for EV charging, but the PV-battery is typically not loaded. -
A regulation of an AC-connected PV inverter is not necessary.
Example: In this case, the Victron inverter transfers 2000W from the DC section, which is currently being generated by the MPPT, although the “Grid/Netzladen” inverter limit of 550W is active.
Installation
The solution is implemented on the NodeRed extension of the Victron VenusGX platform.
For installation following steps are required.
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OpenWB Software-level 2.x required.
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Installation of following NodeRed extensions:
node-red-contrib-ui-multistate-switch -
Activation of permanent Storage
This ensures that the module is restarted with the last selected parameters after a reboot.
Amendment of file „/data/home/nodered/.node-red/settings-user.js”
module.exports = {
contextStorage: {
default: { module:"memory" },
storeInFile: { module:"localfilesystem" }
}
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Adaptation of OpenWB-MQTT-references
To ensure that the correct object-instance are used, the references used on the local WB instance must be entered in the MQTT objects. -
Adaptation of Victron-references
- Ensure that after import of this module the 3 Victron nodes reference the objects “Venus settings / Max inverter power (W)” (read and write) and the MPPT charge controller properly reference to internal Victron objects.
- If no MPPT is available, the “Venus system / MPPTs - power (W)” node can be deactivated.
Exclusion of any liability claims
I am happy to make the solution available to the community under exclusion of any liability claims.
You know, if parameters are set incorrectly on the Victron system, in worst case this can lead to the destruction of the system. The solution has been thoroughly tested by me and ran absolutely reliably. However, use of the solution is at your own risk and I accept no liability whatsoever.
Victron Inverter control.zip (5,2 KB)