An implantable medical device includes a first, short-range telemetry circuit； a second, long-range telemetry circuit； a first power system that powers the first telemetry circuit； and a second power system that powers the second telemetry circuit. The second power system includes an internal charging system and a rechargeable battery coupled to the internal charging system. The internal charging system may be configured for electromagnetic-inductive or RF-transmission coupling with an external charging system. A controller monitors the energy level of the rechargeable battery and provides an signal indicative of the level.
