Hello all, 
I am creating a powerful circuit that is above my comfort/knowledge level. I have a main battery powering 2 BLDC motors with an ODrive, and a secondary battery powering 2 servos and an Arduino + MPU and receiver. I definitely do not want to burn an expensive component, or more importantly, electrocute myself.
(Refer to the graphic below)
My questions:
(1) I am using the same 2S battery to power my Arduino as well as two servos with a Buck converter to give them the 6V they want. Can I connect the the two grounds as shown in the left star ground in the image?
(2) I want to also use the Arduino to communicate to the ODrive (which drives the 2 BLDCs). These are two circuits that I didn’t want to mix, but I see no other way. I have 2 ideas… (1) use an isolator as shown? does this work? (2) connect ALL grounds in a STAR GROUND. Or is there a better way?
-I was worried the ground from my driver could give noise or something to my arduino?
(3) My whole robot is metal, so I was advised to ground the chassis into the Star ground. Is this a good idea, and again, should I star ground everything?
(4) I want a safer way to connect main battery voltage, I was told to look at Connectors instead of relays. Are there connectors that can handle this current? I could not find a good switch that could handle to current except a large boat battery switch.
Thank you all so much, I really need any advice 
-Desperate Student
