More information would be a big help. How are the batteries connected? Two batteries in series should power the servo, they are not that voltage critical. The battery voltages are not directly comparable with the Arduino, you need a regulator either the one on board or an external converter. If it were me I would use a SEPIC converter and set it for about 7.5 volts and power through the Vin input, reason is the additional filtering on the on board power supply. This will definitely impact your battery life which does not appear to be a problem. As you describe the problem it appears your power supply is collapsing. Check your start up code and be sure the servos are turned off. Be sure all the grounds are connected together. This response is to help you get started in solving your problem, not solve it for you.Good Luck & Have Fun!Gil
servo1.attach(9);delay(100);servo2.attach(10);delay(100); // etc.
To prevent a big current surge at startup, insert a 75 ~ 100ms delay between each servo.attach().In setup()Code: [Select]servo1.attach(9);delay(100);servo2.attach(10);delay(100); // etc.