Switch charging session when vehicle identifier changes

[andig]

See #14992.

Currently this is only being done when we see an actual status change to disconnected. Instead, we could check if the vehicle identifier changes. Need to investigate which id changes should trigger new session.

/cc @premultiply

[premultiply]

Possible common indicators for intermediate disconnect could be:

• Status changed (A is the ultimate hard indicator)
• ChargedEnergy jumps back (weak indicator)
• ChargingTime jumps back (weak indicator)
• Identifier changed (be carefull, may change even if session is still running by just swiping any other card. Depends on charger firmware! May be a strong indicator if implemented correctly.)
• TransactionId changed (OCPP only. Is a strong indicator but attention: Id may be reused by charger!)
• ...?

tbc

[kjs-DE]

When charging cable is connected could evcc not check once in a while which vehicle actually shows connected? When changing happened to fast I checked in configuration and the disconnected vehicle showed disconnected (as it should) and the other one showed connected in the status (configuration page). Yet, evcc still thought that the first car is still hooked up.

[andig]

could evcc not check once in a while which vehicle actually shows connected

It does.

When changing happened to fast I checked in configuration and the disconnected vehicle showed disconnected (as it should) and the other one showed connected in the status (configuration page).

This issue ist not about vehicle identification by vehicle API, but about vehicle identification by charger. Doing via API is not possible as API calls are scarce and can only be triggered if we identify vehicle disconnect by charger.