The battery pack BA 2015 is suitable for use in pocket transmitters and receivers of the evolution wireless series G3 100, 300, and 500, 2000, Tourguide SK 2020-D, and EK 1039. It consists of two rechargeable NiMH cells and can be used in place of two AA batteries in the battery compartment. An integrated sensor monitors the temperature during charging in the charger and prevents improper charging of primary cells.