Portable convertible rechargeable battery power supplies are described. The battery power supplies generally comprise a casing enclosing one or more battery power cells and associated electronics and electrical interconnections. The power cells are interconnected with a plurality of external ports allowing for at least one recharge input and at least two outputs: one configured for use with an electronic apparatus, such as a vehicle, and at least one configured for use with one or more personal electronic devices. The apparatus may be an electric vehicle, and the battery power supply may be configured to be secured within the electric vehicle. The outputs for the personal electronic devices may include any suitable port, such as, for example, USB, mini-USB, USB-c, lightning, etc.