This paper addresses the management of independent periodic OS tasks running on battery-powered real-time systems which can change their parameters at run-time for each reconfiguration scenario. A reconfiguration is assumed to be any run-time automatic addition, re- moval, or also update of software tasks according to external events or also user requirements. After any sce- nario, the system can become not feasible and can also lead to a shortage of energy before the next recharge. To resolve these problems, we propose a dynamic strat- egy to be applied at run-time based on grouping tasks in packs. This strategy o↵ers five di↵erent solutions to ensure the system remains up until the next battery recharge while remaining feasible. In this context, we present, in this paper, a new simulator Reconf-Pack for analyzing a reconfiguration and applying the proposed strategy for real-time systems. It is based upon another tool Task-Generator which generates random tasks. Ac- cording to the state of the system after a reconfiguration, Reconf-Pack calculates dynamically a deterministic so- lution. Moreover, it compares our pack-based solutions to related works.