Embodiments are described which provide for a rechargeable battery pack for use in a flashlight. The rechargeable battery pack may include a rechargeable cell, one or more conductive contacts to provide power to a flashlight, and a charging port. The rechargeable battery pack may include these components as a self-contained unit inside a single casing. A flashlight may be configured to accept the rechargeable battery pack in a cavity of the flashlight as well as a non-rechargeable battery pack of a similar profile. Embodiments are also described which provide for a rechargeable pen light with conductive body portions, such that the pen light may be charged through insertion in a charging cover. Other embodiments may be described and claimed.