How much time does it take to charge the battery?

It depends on the type of the charging system used, on the type of the car battery charger and on the capacity of the batteries themselves.
Roughly speaking, the charging system can be single-phase (less powerful) or three-phase (more powerful).
The battery charger can work with one of this configuration or both of them.
Approximately you can have a full charge in 8 hours, with the “slow” single-phase charge; or in only one hour with the “fast” three-phase system.