Mobile nodes have limited computing resources, among which battery is one of the most important resources, since the lifetime of a node depends on the amount of battery and energy usage in the node. Application processes on mobile nodes include those are important for the users for certain duration of time, and those not. Therefore, exhausting whole battery for running non-important ones such as games, would be waste of energy. To maximize the user satisfactions with limited amount of energy, a sophisticated pacing mechanism is required for energy usage. We propose a process lifetime reservation system, called pSurvive. It enables users to reserve energy for running specific processes for a certain duration of time. Users are allowed to run any applications until the total energy consumption reaches the deadline to run the reserved processes. pSurvive enables this with the following three novel mechanisms. First, P-Monitor monitors running processes and devices (e.g. NIC, LCD, etc.) in a node for their energy consumption. Second, P-Analyzer estimates future energy consumption based on the energy usage information given by P-Monitor. Third, P-Reserver accepts energy reservation requests from users, and pace the energy consumption by shedding unnecessary tasks. This paper first discusses requirements for energy reservation on mobile nodes. It then reports the design and the implementation of pSurvive for Android mobile nodes, and shows that pSurvive achieves process lifetime reservation based on the fine-grained energy monitoring.