A handheld electronic device that includes a first battery and a holster that includes a second battery and a charging apparatus. When the handheld electronic device and the holster are electrically connected together, the charging apparatus charges the first battery on the handheld electronic device from the second battery on the holster when the first battery charge has been depleted to a given level and the second battery charge is above a second given level. Alternatively, if the first battery charge is above a third given level the first battery charges the second battery if the second battery is not fully charged. The holster further includes a microcontroller that communicates with a microprocessor on the handheld electronic device to identify alerts and activate a notification device powered by the second battery on the holster.