At any rate, all I have to do is run the tests for my robot with fully charged batteries, the same for the competition. It only has to go a maximum of 10 meters...
ok but make sure the batteries are fully charged when you test it and after each run
if you use a voltage regulator ( a switching one, not a regulated one) then you can regulate the amount of voltage that they draw
use one regulator per servo .
Also, what is the voltage all the batteries, how many AAs or whatever battery you are using?