An apparatus heats fluids. A number of lithium-ion cells are positioned within a housing. A first connector is positioned on a first end of the housing and operably connected to the number of lithium-ion cells. The first connector is configured to receive electrical power from a power source. A second connector is positioned on a second end of the housing and operably connected to the number of lithium-ion cells. A heating element has a tube for transferring fluid. The heating element is configured to connect to the second connector. A controller is positioned within the housing and operably connected to the number of lithium-ion cells and the second connector. The controller is configured to monitor a rate at which the electrical power is received by the heating element and limit an amount of the electrical power received by the heating element when the rate reaches a predetermined level.
