Robot can't rotate, CIMS stop working !

[cilginbilgin]

We have almost finished our robot and started testing it. When we tried to turn, the robot doesn't move, but when we try to drive straight, it works well. We believe that the CIMs stop working since there is a red light on the power distribution board.

Also the CIM that we used for the ball lifter stops with a clicking sound and stays like that for a couple of seconds and starts working again. There is again a red light on the power distribution board in this case too.

However, when we work with a totally full battery (13.50 volts) the CIMs work a lot better and longer.

There is no mistake with the code so we believe the cause of the problem is low voltage.

What should we do, what might be the reason ?