The whole project got more complex than initially thought.
It is still work in (slow) progress, but here is an update anyhow.
The node-red charge control needs to be manually enabled. I did not find an easy and energy friendly way to figure out if the car is parked by the house and plugged in, because in all other scenarios the node-red charge control should not intervene.
Here is the current dashboard. On the left side I can set the charge limit for the battery. In the middle column I set the charge strategy and enable/disable the node-red based charge control.
If it is enabled, then the right column fills up with status information about the charge progress.
And here are two images of the nodes and the wiring. The first contains the nodes to draw the dashboard. The second one contains the long logic chain for the charging.
