This article presents a new version of the dynamic source routing (DSR) protocol that favours the selection of a route containing nodes with high battery levels, in order to maximize the lifetime of the ad hoc mobile network as a whole. This proposal implies little modifications to the original algorithm. After a quantitative analysis, we see simulation results that indicate that the proposed scheme, SEADSR (simple energy aware DSR), outperforms the standard DSR in terms of network survivability and network capacity.