Some embodiments of an infusion pump system can employ a number of power management techniques to avoid using substantially excessive power during operation of the pump drive system. Thus, the infusion pump system can draw upon the energy supply in an efficient manner that extends the useful life on the power supply. Furthermore, the infusion pump system can be configured estimate an amount of power remaining to operate the pump system without the requirement of directly detecting the remaining charge on power supply device (e.g., without detecting the remaining charge on a battery). As such, the infusion pump system can readily inform a user of a particular estimated amount of time remaining for medicine dispensing operations.