Questions about okapi chassis controller power

we are trying to use skid chassis controller to control arm lifting. we used the factory to create a chassis with 2 motors and default pid.

we use forward () to do the lifting. while we try to use full power 1.00 to drive, the maximum voltage we can read from the motors are only about 5 volts. how do we drive with full power of 12 volts.

document says forward () runs in open loop mode. Our understanding is that it opens loop only for position pid. Other pid is still in closed loop to keep two motors in synch.

We suspect the default pid setting caused motors running well below max voltage.

to bring up motor power , do we need to set max power or tune the pid or other tricks anyone can suggest?