METHOD AND APPARATUS FOR PROVIDING UNINTERRUPTIBLE POWER

An uninterruptible power supply comprising an input, an output, a plurality of battery modules that provide backup power, a power circuit coupled to the input, the plurality of battery modules and the output to provide power derived from the input and/or the backup power to the output, a controller, a return line coupled to the controller and to each of the plurality of battery modules, and a first sense line coupled to the controller and to each of the plurality of battery modules, wherein each respective battery module is arranged to simultaneously provide a respective signal on a respective characteristic signal line that is coupled to the first sense line, and wherein the controller is configured to determine a numeric quantity of battery modules in the plurality of battery modules based on the respective signals detected by the controller on the first sense line.