Abstract: A large battery array, particularly for use in an electric vehicle, is formed of multiple modules, each containing plural battery cells and module management electronics. Each battery module has a nominal output voltage in the range of about 5 volts to about 17 volts. A controller communicates with individual battery modules in the array and controls switching to connect the modules in drive and charging configurations. The module management electronics monitor conditions of each battery module, including the cells it contains, and communicates these conditions to the controller. The module management electronics may place the modules in protective modes based upon the performance of each module in comparison to known or configurable specifications. The modules may be pluggable devices so that each module may be replaced if the module is in a permanent shutdown protective mode or if a non-optimal serviceable fault is detected.