Example implementations relate to selectively enabling backup power to nodes. For example, a system includes a plurality of compute nodes, where each node includes a plurality of loads. The system also includes at least one backup power supply and control module coupled to the nodes and to the at least one backup power supply. The control module is to selectively enable an output of power from the at least one backup power supply to the nodes based on a comparison of a power capacity of the at least one backup power supply and a backup power demand of the nodes.