I been working on a small project at home. I have a mobile robot with 2 servos operating the wheels and 6 others operating an arm, making it a total of 8 servos. I'm currently using Arduino Mega and an external power supply, a modified ATX power supply (5V 30A). I have a battery from a previous R/C car project, 7.2V 4500mAh. I would like to use this battery to power the robot. I've tried connecting it directly but the servos do not switch on. I get a big voltage drop and current drop, as many of you figured out already. I thought if I made a simple voltage follower it would work, but didn't. How else can I power these servos without buying a Servo Controller. I would like to make a circuit with parts that can easily be found locally. Any help that can be offered, would be great.