This document discusses energy efficiency in mobile ad hoc networks (MANETs). It begins by explaining that wireless devices have limited battery capacities, so energy efficiency is important. It then discusses several routing protocols that aim to improve energy efficiency, including Minimum Transmission Power Routing (MTPR), Minimum Battery Cost Routing (MBCR), Min-Max Battery Cost Routing (MMBCR), and Conditional Min-Max Battery Cost Routing (CMMBCR). The document also proposes a new protocol called Min-Max Residual Energy in AOMDV (MMRE-AOMDV) and presents simulation results showing it performs better than AOMDV and AODV in terms of energy consumption and end-to-end delay