An electronic vapor provision device comprising a battery assembly and a vaporizer, wherein the battery assembly comprises a power cell and a computer, the vaporizer is releasably connectable to the battery assembly and the computer comprises a computer processor and a memory, wherein the computer is configured to detect whether the vaporizer is connected to the battery assembly without use of the electronic vapor provision device by a user, and to substantially remain in a sleep mode until the vaporizer is connected to the battery assembly.