Battery power supply to servo, stand alone, help.
 

Thank you in advance. A friend of mine gave me a project of a bruder dirt conveyor having a servo to power the belt. It works great when I power it off of an RC car receiver. However trying to power it off of a battery pack of any kind is not working. The servo is a Hobico CS-70. I've tried 4 AA batteries for 6v, a 2s lipo for 7.4v, but it only engages and will not actually turn. Any advice?
Thanks and have a great day.
Bert

You have to connect ground wire of your battery pack to the receiver ground wire. Did you remember to do that?

Your servo has 3 wires at the plug. Red and black are the battery power wires, positive and negative. The 3rd wire is gets a control signal from the receiver, though it actually originates at the transmitter.
the servo will not work withonly the battery connected - it needs the control signal, which can come from a receiver or from a servo driver which are also referred to as a servo tester.
The info about the ground wire is correct, it has to be connected, but by itself will not operate a servo. It has to have a control signal.