Battery voltage determines the speed that the motor will run at. A motor intended for 11.1 volts will run at about 2/3 the speed if you reduce to 7.4 volts (assuming no load).

The current the motor draws will depend on the size of prop you put on it. The motor will try and spin up to its no-load speed, with a small prop this will take less current as the work done will be less.

This is the short version!

Terry