The invention relates to a method and to a device (1) for charging batteries (10), in particular lead-acid batteries, having a predetermined end-of-charge voltage (ULS). In order to charge the battery (10) as efficiently and smoothly as possible, and in order to increase the service life of the battery (10), according to the invention the charge state of the battery is established before the charging process and a charging current (IL) or a charging voltage (UL) is applied to the battery (10) during the charging process and is regulated in such a manner that the charging voltage (UL) is increased during a predetermined charging time (t'charge) between a charge starting voltage (ULA) and the end-of-charge voltage (ULS).