The disclosure describes a method for determining a coulombic efficiency of battery modules of a rechargeable battery using a circuit arrangement connected to the battery modules and that has a plurality of switching modules for selectively connecting every single one of the battery modules in a common current path or for alternatively isolating every single one of the battery modules from the common current path and from at least one power semiconductor element, which can be operated in linear mode, for regulating the current that flows through the current path. The switching modules are used to select at least one of the battery modules and to connect it in the current path while all other battery modules are isolated from the current path by the switching modules. The selected battery module is subjected to at least one discharge process and at least one charging process via the current path.