A battery-charging device includes: a housing that is configurable from a first shape into at least a second shape; and a direct current-to-direct current battery charger disposed within the housing. The direct current-to-direct current battery charger is configured to convert direct current power, received from a source external to the battery charger, into a direct current source for supplying energy to a rechargeable battery that is electrically connected to the battery charger. The battery-charging device may further include a communication element configured to communicate, with a portable electronic device that includes the rechargeable battery, using a short-range communication technology.