In Mobile Ad-Hoc Network (MANET), whenever a node runs out of energy the the probability of network partitioning will be increased. Since most of mobile nodes rely on a limited battery resource, the nodes`` energy depletion becomes one of the main threats to the lifetime of the ad hoc network. This thesis presents new routing algorithms for maximizing the lifetime of a MANET. The solution approach is reducing the energy consumption at routing discovery phase and establishing suitable routing paths with respect to energy-saving. At the routing discovery phase, we use a dynamic flood filtering algorithm to eliminate the nodes that are predicted not to participate in the final routing paths. The prediction rules are based on energy requirement by each connection, energy availability of each node, and neighbor nodes`` status. Finally, at the destination node, by using an energy-efficient route selection algorithm, the selected routing path would have small energy consumption with an ample residual energy capacity. The simulation results show that these proposed solution can significantly last the network lifetime. In addition, the thesis also shows that we can implement these proposed solutions in a real world testbed by modifying the existing on-demand implemented routing protocols such as Kernel-AODV  and AODV-UU . A battery monitoring tools is implemented for providing battery information to routing discovery phase. The routing discovery phase can be modified by adding some modules for calculating the residual energy, energy requirement of incoming connection and checking the neighbor link status of each node.