The battery charger is the device between the grid and the battery in your EV.  It is much more then a thing that fills up the battery to 100%.

The battery system in your EV monitors the charge situation and also during charging, the conditionof individual cells.

The Smart Battery Charger
- works togehter with the EV's battery management system, to charge or decharge the battery within healthy operating parameters for the battery cells.
- follows your users preferences how much it should charge the battery, at what time.
- communicates with the utility or other supplier or organisation, such as the Grid Cloud, to get the lowest price when charging, and the best price when delivering electricty.
- It could be set to preferably use surplus power from your home solar panels, or your piece of the communal windturbine.