A multi-mode communication device (100) uses a first wireless modem (118) and a second wireless modem (120) which operates independently to facilitate communication over different air interfaces. Both modems are powered by a common battery (105). When the first wireless modem engages in a communication activity, the second wireless modem's maximum operating power level is reduced. When the first wireless modem ceases communication activity, the second wireless modems full operating power range is restored.