Abstract: An uniterruptible power supply (UPS) system that includes one or more NiMH or Li-ion batteries is provided. In one general aspect, the invention features a power supply system including a power input to receive input power from a power source, a power output to provide output power to a load, at least one NiMH or Li-ion battery having a battery output that provides battery power, at least one power module coupled to the power input to receive the input power, coupled to the battery output to receive the battery power and coupled to the power output to provide the output power, a controller, coupled to the at least one power module, constructed and arranged to monitor and control the output power from the at least one power module. A UPS system using a NiMH or Li-ion battery typically uses less space and weigh less than a UPS having a lead acid battery. Additionally, NiMH and Li-ion batteries perform better at temperature extremes than do comparable lead acid batteries.

Abstract: A system for controlling multiple energy storage devices in an uninterruptible power supply (UPS) system is provided. In one embodiment of the invention, the system generally includes a charger coupled to a direct current (DC) bus of the UPS system, and two or more energy storage circuits, each of which includes a power regulator coupled to the charger and coupled to the DC bus, at least one energy storage device coupled to the power regulator, and a processor coupled to the power regulator for controlling the charge and discharge of the at least one energy storage device. In another embodiment of the invention, digital communication between two or more controllers is accomplished over the DC bus through use of the Control Area Network (CAN) protocol.