A vehicle data recording unit for installation in a motor vehicle having a housing. Within the housing is an electronic memory and control unit and a battery receptacle for receiving a buffer battery for the memory and control unit. The battery receptacle has a battery compartment delimited by a first stop and a second stop, situated opposite the first stop, for holding a first buffer battery between the first stop and the second stop. To make it easy to use buffer batteries of different physical sizes, a third stop is arranged between the first stop and the second stop, which has a smaller length than the first buffer battery, in the battery compartment between the third stop and the first stop, such that optionally the first buffer battery or the second buffer battery can be held in the battery compartment.