Monte, is correct on what he has posted...also, Current flows from Negative to Positive. So, the Grounding is just as important as anything else in a circuit.
Another point, are ground loops. So, the best way to connect grounds are from a central point, and "crow Foot" out from that point.
Also, It never occurred to me about the bonding/ground jumper from the heads to the main ground...great point, since hi-voltage (RF) would be bled back to the chassis/ground/battery.
The Battery is a power source, but also a great filter capacitor for all kinds of noise.
BTW, I am a BSEE, and I have learned a few things from you all!
