This disclosure relates to systems, methods, and apparatus for limiting or throttling an activity of an accessory device communicatively coupled to a computing device. The activity of the accessory device is limited or throttled in order to reduce electromagnetic interference and improve signal quality of a wireless communication in which the computing device is participating. In some embodiments, a decision to throttle can be based on battery charge level of the computing device. For example, in some embodiments, the accessory device is an accessory battery charger configured to provide power to the computing device when a power outlet is not immediately available. If the signal quality of a phone call from the computing device is diminished or the user is in an area of low signal coverage, the accessory battery charger can be limited or throttled in order to prevent interference between the accessory battery charger and computing device.