Devices, systems and methods for controlling fluid temperatures from more than one fluid containers prior to their infusion into a human body are disclosed. The device includes a power supply source for providing power; an input/output interface for receiving fluid temperature data from thermal sensors and for transmitting duty-cycle signals to each of the fluid warming unit; a processing unit for comparing fluid temperature data with a permissible fluid temperature range, for calculating a fluid temperature differential, and for apportioning the available work cycle of the power supply source; and a controller for adjusting the duty-cycle of each fluid warming unit based on the fluid temperature differentials, so that during each work cycle all available power provided by the power supply source is delivered to only one of the fluid warming units at a time.