Recently, relay agents selection schemes were introduced to support downlink multicasting in WiMAX single frequency networks. Such schemes were devised to work cooperatively in order to facilitate reliable Multicast Broadcast Multimedia Services (MBMS) traffic delivery over wireless channels without any consideration to mobile relay agents’ battery energy levels. In this paper, we introduce a battery-aware balancing algorithm to operate in conjunction with these relay agents selection schemes proposed in the open literature. A simulation model, used to present the effect of “before” and “after” the battery–awareness selection criterion, highlighted the benefit of using such algorithms in prolonging network lifetime with emphasis on reliable delivery.