A power tool comprising a power tool housing, an auxiliary power source, a user input for user control of power tool operation, and a controller. The controller is configured to receive a control signal from the user input, control the power tool in response to the control signal, receive, from a sensor, a signal indicative of an operational characteristic of the power tool, and selectively provide energy from the auxiliary power source to a load of the power tool based on the operational characteristic of the power tool.