I probably have a power supply issue with my allbot VR408. I am using the Arduino code supplied by Velleman and 4 new Energizer alcaline batteries. The robot is working correctly only when the USB cable is connected to my laptop. When it is not connected, the arduino Mega board misbehaves and restarts all the time. Voltage measurement shows that the 12V boost voltage drops down to 4V when servos switch on and the 4 blue leds light decrease, which explains the Arduino board misbehaviour. Also, the 5-6V battery voltage drops down to 2.5V.
Could you help me with that?