V2 power

so I have a build your first bot part 2 and I have the power set up with about 5.5V on the far left pin grounded on the far right and to the battery clip about 3.8V (low batteries) for fun to see if I can get him running any better. I’m also trying to add arms in the nearby future so I thought it would be good to learn. THing is when I hook this up his servos go on crack and no even all the motors move. any suggestions?!