one or more electric traction motors coupled to one or more wheels as the sole source of motive power for the vehicle, wherein the plug-in electric vehicle is free from an internal combustion engine mechanically coupled to the one or more wheels;

a rechargeable battery system including one or more batteries, wherein the rechargeable battery system is;

connectable to an external electrical source to recharge the rechargeable battery system;

an auxiliary electric power source;

a power distribution system responsive to power control signals to controllably couple electric power from the rechargeable battery system and the auxiliary electric power source to the one or more electric traction motors;

one or more operator controls to provide operator vehicle control signals;

one or more failure sensors, each sensor identifying a vehicle condition indicating a battery charge limitation and providing failure signals representative of the battery charge limitation; and

a controller coupled to the power distribution system, the one or more operator controls and the one or more failure sensors, the controller configured to produce the power control signals and to operate in a normal mode and one or more of a plurality of derate modes, wherein:

the controller produces normal traction power control signals in response to the operator control signals during operation in the normal mode, and wherein power of the rechargeable battery system and/or the auxiliary electric power source are depleted at a first rate during operation of the vehicle when the controller is operating in the normal mode; and

in response to the failure signals, the controller selects one or more of the plurality of derate modes, and produces derated traction power control signals in accordance with the selected one or more of the plurality of derate modes in response to the operator control signals during operation in the one or more of the plurality of derate modes, wherein power of the rechargeable battery system and/or the auxiliary electric power source are depleted at a second rate during operation of the vehicle when the vehicle controller is operating in the one or more of the plurality of derate modes, and wherein the second rate is less than the first rate to conserve the power of the rechargeable battery system and/or the auxiliary power source.