The Internet of Things (IoT) often includes traditional edge, fog, and cloud layers. Edge devices collect data, the fog layer performs partial or total data processing, and applications store or access these data. The data processing performed by fog devices involves aggregating data, performing complex queries, and detecting anomalies. However, performing these tasks requires complex management to avoid the energy exhaustion of fog devices, which are typically powered by batteries. Considering this context, balancing energy consumption in IoT becomes a challenge in which battery-powered fog devices execute CPU-demanding applications. This paper proposes RAS-IoT (Replacement Adaptive System for IoT), which autonomously moves containers among IoT devices to balance power consumption and extend their battery lifetime. The results indicate that the proposed solution increases the overall battery life of the devices, and the additional energy consumption of the container is outperformed by raising the device’s lifetime.