Abstract: An arrangement for charging a plurality of batteries that are connected in series, where the total voltage across all the batteries that are connected in series is a predefined system voltage, includes an arrangement for controlling the voltage across each battery separately, so that the system voltage is not exceeded and so that the voltage across one of the batteries is higher than the voltage across each individual other battery. The arrangement can be arranged to be able to charge batteries on, for example, a vehicle with two batteries that are connected in series, where the charging voltage needs to be higher than half the system voltage and at the same time the system voltage is not permitted to exceed a predetermined level.