Once you turn on the power to the esc it depends if it is on red or green. If it is on red (low voltage sensor off) then the esc is set for NiMH or if it is green (low voltage sensor on) then it is set for Lipo. The switch between the two hold down the esc power button for ten seconds and it should change color and the motor make an audible tone. Assuming that you have the Traxxas Venilion xl3 esc and brushless motor.